JP7719611B2 - Fluorene compound and resin using same - Google Patents

Description

The present invention relates to compounds having a 9,9-bispolycyclic arylfluorene skeleton and resins using the same.

In the field of optical materials, compounds with a 9,9-bisarylfluorene skeleton and resins made from these compounds as raw materials (or polymer components) have attracted attention due to their excellent optical properties, such as a high refractive index, low Abbe number, low birefringence, and high transparency, as well as their heat resistance. In recent years, the properties required of optical components have tended to become more sophisticated, and Patent Documents 1 to 5, for example, describe compounds in which the aryl group substituted at the 9,9-position of the fluorene skeleton is a polycyclic aryl group.

JP 2009-155253 A JP 2011-68624 A JP 2016-69643 A Japanese Patent Application Laid-Open No. 2017-179323 JP 2018-168124 A

The compounds having a 9,9-bisarylfluorene skeleton described in Patent Documents 1 to 5 have relatively high optical properties and heat resistance. On the other hand, for use as optical components, it is also extremely important that they are resistant to coloration.

Therefore, an object of the present invention is to provide a fluorene compound that can suppress discoloration even in high-temperature environments, and a resin made from this fluorene compound.

Another object of the present invention is to provide a method for suppressing discoloration of fluorene compounds.

Another object of the present invention is to provide a method for improving the heat resistance of resins made from fluorene compounds.

Another object of the present invention is to provide a method for suppressing discoloration of resins made from fluorene compounds.

As a result of extensive research to achieve the above-mentioned objectives, the inventors discovered that by adjusting the content of specific impurities that may be mixed into compounds having a 9,9-bispolycyclic arylfluorene skeleton during the manufacturing process, etc., to a predetermined range, coloration can be effectively suppressed even in high-temperature environments, leading to the completion of the present invention.

That is, the fluorene compound of the present invention is represented by the following formula (1), and is a compound in which the content of the compound represented by the following formula (2) is 0.5% or less in terms of area percentage by HPLC, the content of the compound represented by the following formula (3) is 0.3% or less in terms of area percentage by HPLC, and the residual sulfur is 10 ppm by mass or less.

(wherein Z ^1a and Z ^1b each independently represent a polycyclic arene ring;
^R1 represents a substituent; n1 represents an integer of 0 to 8;
R ^2a and R ^2b each independently represent a substituent; n2a and n2b each independently represent an integer of 0 or more;
A ^1a and A ^1b each independently represent a linear or branched alkylene group.

(wherein ^R3 represents a substituent, and n3 represents an integer of 0 to 8).

(wherein ^Z2 represents an arene ring;
^R4 represents a substituent; n4 represents an integer of 0 or more;
^A2 represents a linear or branched alkylene group).

In the formula (1), Z ^1a and Z ^1b may be a naphthalene ring or a biphenyl ring, the content of the compound represented by the formula (2) may be about 0.2% or less, the content of the compound represented by the formula (3) may be about 0.05% or less, and the residual sulfur may be about 1.5 mass ppm or less.

The fluorene compound represented by formula (1) may have a content of the compound represented by formula (4) below of 0.01 to 10% in terms of HPLC area percentage.

(In the formula, ^Z3a and ^Z3b each independently represent an arene ring,
^R5 represents a substituent; n5 represents an integer of 0 to 8;
R ^6a and R ^6b each independently represent a substituent; n6a and n6b each independently represent an integer of 0 or more;
^A3a and ^A3b each independently represent a linear or branched alkylene group, and m3a and m3b each independently represent an integer of 0 or greater, provided that when both ^Z3a and ^Z3b are polycyclic arene rings, m3a and m3b cannot simultaneously be 1.

The fluorene compound represented by formula (1) may have a content of a compound represented by formula (4) in which one of m3a and m3b is 0 and the other is 1 of 0.01 to 1% in terms of HPLC area percentage.

The fluorene compound represented by formula (1) may have a content of a compound represented by formula (4) in which one of m3a and m3b is 1 and the other is 2 of 0.01 to 5% in terms of HPLC area percentage.

The fluorene compound represented by formula (1) may have a content of the compound represented by formula (11) below of 0.1 to 10% in terms of HPLC area percentage.

(In the formula, Z ^8a and Z ^8b each independently represent an arene ring,
R ¹⁷ represents a substituent; n17 represents an integer of 0 to 8;
R ^18a and R ^18b each independently represent a substituent; n18a and n18b each independently represent an integer of 0 or more;
A ^8a to A ^8d each independently represent a linear or branched alkylene group, m8a and m8b each independently represent an integer of 0 or more, and m8c and m8d each independently represent an integer of 0 to 2, provided that m8c and m8d are not simultaneously 0).

The present invention includes a resin containing (using as a raw material) a fluorene compound represented by formula (1). The resin may be a thermoplastic resin containing an ester bond in the main chain. The resin may also be a thermoplastic resin containing a carbonate ester bond in the main chain.

The present invention also encompasses a method for suppressing discoloration of the compound represented by formula (1) in a molten state by adjusting the content of the compound represented by formula (2) to 0.5% or less in terms of area percentage by HPLC, the content of the compound represented by formula (3) to 0.3% or less in terms of area percentage by HPLC, and the residual sulfur to 10 ppm by mass or less.

Furthermore, the present invention also encompasses a method for improving the glass transition temperature of the resulting resin by using the compound represented by formula (1) as a resin raw material, and a method for reducing the b* (color difference b* value) of the resulting resin.

In this specification and claims, the term "diol unit" refers to a structural unit derived from a diol component, i.e., a unit (or divalent group) obtained by removing hydrogen atoms from two hydroxyl groups of the corresponding diol, and the term "diol component" (including compounds exemplified as diol components) may be used synonymously with the corresponding "diol unit."

Similarly, the term "dicarboxylic acid unit" refers to a structural unit derived from a dicarboxylic acid component, i.e., a unit (or divalent group) obtained by removing OH (hydroxyl group) from two carboxyl groups of the corresponding dicarboxylic acid. The term "dicarboxylic acid component" is used to refer to not only dicarboxylic acids but also derivatives usable as polymerization components, such as ester-forming derivatives. Examples of the ester-forming derivatives include dicarboxylic acid esters, dicarboxylic acid halides, and dicarboxylic acid anhydrides. Examples of the dicarboxylic acid esters include dicarboxylic acid component alkyl esters, particularly lower alkyl esters, such as _C1-4 alkyl esters such as methyl esters, ethyl esters, and t-butyl esters. Examples of the dicarboxylic acid halides include dicarboxylic acid chlorides and dicarboxylic acid bromides. The ester-forming derivatives may be monoesters (half esters) or diesters. The term "dicarboxylic acid component" (including compounds exemplified as dicarboxylic acid components) may be used synonymously with the corresponding "dicarboxylic acid unit."

In this specification and claims, the number of carbon atoms in a substituent may be indicated as C ₁ , C ₆ , C ₁₀ , etc. For example, an alkyl group having 1 carbon atom is indicated as "C ₁ alkyl," and an aryl group having 6 to 10 carbon atoms is indicated as "C _6-10 aryl."

In addition, in this specification and claims, unless otherwise specified, the term "fluorene compound" refers to a compound represented by formula (1).

Furthermore, in this specification and claims, "HPLC" means high performance liquid chromatography.

The fluorene compound (or a composition containing a fluorene compound and impurities) of the present invention can suppress or reduce coloration (or discoloration) even in high-temperature environments. Therefore, the fluorene compound has excellent heat resistance. Furthermore, when this fluorene compound is used to prepare a resin, coloration (or discoloration) of the resulting resin can be suppressed or reduced. Furthermore, the heat resistance of the resulting resin can be improved.

[Fluorene compound represented by formula (1)]
The fluorene compound of the present invention is represented by the following formula (1).

(wherein Z ^1a and Z ^1b each independently represent a polycyclic arene ring;
^R1 represents a substituent; n1 represents an integer of 0 to 8;
R ^2a and R ^2b each independently represent a substituent; n2a and n2b each independently represent an integer of 0 or more;
A ^1a and A ^1b each independently represent a linear or branched alkylene group.

In the formula (1), examples of the polycyclic arene ring (polycyclic aromatic hydrocarbon ring) represented by rings ^Z1a and ^Z1b include a fused polycyclic arene ring (fused polycyclic aromatic hydrocarbon ring) and a ring-assembled arene ring (ring-assembled aromatic hydrocarbon ring).

Examples of fused polycyclic arene rings include fused bicyclic arene rings, fused tricyclic arene rings, and other fused bicyclic to tetracyclic arene rings. Examples of fused bicyclic arene rings include fused bicyclic _C10-16 arene rings such as naphthalene rings and indene rings. Examples of fused tricyclic arene rings include anthracene rings and phenanthrene rings.

Preferred fused polycyclic arene rings include fused polycyclic C _10-16 arene rings such as naphthalene ring and anthracene ring, more preferably fused polycyclic C _10-14 arene ring, and particularly preferably naphthalene ring.

Examples of ring-assembled arene rings include biarene rings and terarene rings. Examples of biarene rings include biC _6-12 arene rings such as biphenyl rings, binaphthyl rings, and phenylnaphthalene rings. Examples of the phenylnaphthalene rings include 1-phenylnaphthalene rings and 2-phenylnaphthalene rings. Examples of terarene rings include terC _6-12 arene rings such as terphenylene rings.

Preferred ring-assembly arene rings include biC _6-10 arene rings, and a biphenyl ring is particularly preferred.

The types of rings Z ^1a and Z ^1b may be the same or different, and are usually the same. Of rings Z ^1a and Z ^1b , C _10-14 arene rings such as naphthalene rings and biphenyl rings are preferred, and a naphthalene ring is particularly preferred. When rings Z ^1a and Z ^1b are fused polycyclic arene rings such as naphthalene rings, it appears that impurities such as sulfur components can be more effectively reduced.

The substitution positions of rings Z ^1a and Z ^1b bonded to the 9-position of the fluorene ring are not particularly limited. For example, when rings Z ^1a and Z ^1b are naphthalene rings, they may be either the 1-position or the 2-position, preferably the 2-position. When rings Z ^1a and Z ^1b are biphenyl rings, they may be either the 2-position, the 3-position, or the 4-position, preferably the 3-position.

Examples of the substituent represented by ^R1 include a hydrocarbon group, a cyano group, and a halogen atom.

Examples of hydrocarbon groups include alkyl groups and aryl groups. Examples of alkyl groups include linear or branched C _1-6 alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, and t-butyl. Examples of aryl groups include C _6-10 aryl groups such as phenyl.

Examples of halogen atoms include fluorine atoms, chlorine atoms, and bromine atoms.

Of these groups R ¹ , alkyl groups, cyano groups and halogen atoms are preferred, and among these, alkyl groups, particularly linear or branched C _1-4 alkyl groups such as methyl groups are preferred.

The number of substitutions ⁿ¹ of the group R1 is, for example, an integer of about 0 to 6, and preferred ranges are, in the following stepwise order, integers of 0 to 4, integers of 0 to 3, and integers of 0 to 2, more preferably 0 or 1, and particularly 0. The numbers of substitutions in the two different benzene rings constituting the fluorene ring may be the same or different. The types of groups ^R1 substituting the different benzene rings may be different, but are usually often the same. When n1 is 2 or greater, the types of the two or more groups ^R1 substituting the fluorene ring may be the same or different. The substitution position of the group ^R1 is not particularly limited, and may be, for example, the 2nd to 7th positions of the fluorene ring, such as the 2nd, 3rd, and/or 7th positions.

Examples of the substituents represented by the groups ^R2a and ^R2b include a halogen atom, a hydrocarbon group, an alkoxy group, a cycloalkyloxy group, an aryloxy group, an aralkyloxy group, an alkylthio group, a cycloalkylthio group, an arylthio group, an aralkylthio group, a mercapto group, an acyl group, a carboxyl group, an alkoxycarbonyl group, a carbamoyl group, a nitro group, a cyano group, an amino group, a substituted amino group, and groups in which these substituents are bonded to each other.

Examples of halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

Examples of hydrocarbon groups include alkyl groups, cycloalkyl groups, aryl groups, and aralkyl groups.

Examples of the alkyl group include linear or branched C _1-10 alkyl groups such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, s-butyl, and t-butyl. Preferred alkyl groups are linear or branched C _1-6 alkyl groups, and more preferred are linear or branched C _1-4 alkyl groups.

Examples of the cycloalkyl group include a C _5-10 cycloalkyl group such as a cyclopentyl group and a cyclohexyl group.

Examples of the aryl group include _C6-12 aryl groups such as a phenyl group, an alkylphenyl group, a biphenylyl group, and a naphthyl group. Examples of the alkylphenyl group include a methylphenyl group (tolyl group) and a dimethylphenyl group (xylyl group).

Examples of the aralkyl group include a C _6-10 aryl-C _1-4 alkyl group such as a benzyl group or a phenethyl group.

Examples of the alkoxy group include linear or branched C _1-10 alkoxy groups such as methoxy, ethoxy, propoxy, n-butoxy, isobutoxy, s-butoxy and t-butoxy groups.

Examples of the cycloalkyloxy group include a C _5-10 cycloalkyloxy group such as a cyclohexyloxy group.

Examples of the aryloxy group include a C _6-10 aryloxy group such as a phenoxy group.

Examples of the aralkyloxy group include a C _6-10 aryl-C _1-4 alkyloxy group such as a benzyloxy group.

Examples of the alkylthio group include C _1-10 alkylthio groups such as methylthio, ethylthio, propylthio, n-butylthio and t-butylthio.

Examples of the cycloalkylthio group include a C _5-10 cycloalkylthio group such as a cyclohexylthio group.

Examples of the arylthio group include a C _6-10 arylthio group such as a thiophenoxy group.

Examples of the aralkylthio group include a C _6-10 aryl-C _1-4 alkylthio group such as a benzylthio group.

Examples of the acyl group include C _1-6 acyl groups such as an acetyl group.

Examples of the alkoxycarbonyl group include C _1-6 alkoxy-carbonyl groups such as a methoxycarbonyl group.

Examples of the substituted amino group include a dialkylamino group and a bis(alkylcarbonyl)amino group. Examples of the dialkylamino group include a di-C _1-4 alkylamino group such as a dimethylamino group. Examples of the bis(alkylcarbonyl)amino group include a bis(C _1-4 alkyl-carbonyl)amino group such as a diacetylamino group.

Examples of groups in which these substituents are bonded to each other include alkoxyaryl groups, specifically C _1-6 alkoxyC _6-10 aryl groups such as methoxyphenyl groups; alkoxycarbonylaryl groups, specifically C _1-6 alkoxy-carbonylC _6-10 aryl groups such as methoxycarbonylphenyl groups; and the like.

Representative examples of these groups ^R2a and ^R2b include halogen atoms, hydrocarbon groups, alkoxy groups, acyl groups, nitro groups, cyano groups, and substituted amino groups. When the number of substitutions n2a and n2b is 1 or more, preferred groups ^R2a and ^R2b include alkyl groups, aryl groups, and alkoxy groups. As the alkyl group, a linear or branched _C1-6 alkyl group such as a methyl group is preferred, as the aryl group, a _C6-12 aryl group such as a phenyl group is preferred, and as the alkoxy group, a linear or branched _C1-4 alkoxy group such as a methoxy group is preferred. Among these, alkyl groups and aryl groups are preferred, more preferably linear or branched _C1-4 alkyl groups such as a methyl group, and _C6-10 aryl groups such as a phenyl group, even more preferably a methyl group or a phenyl group, and particularly preferably a methyl group.

The substitution numbers n2a and n2b of the groups R ^2a and R ^2b can be appropriately selected depending on the types of rings Z ^1a and Z ^1b , and may be, for example, an integer of about 0 to 8, preferably an integer of 0 to 6, an integer of 0 to 4, an integer of 0 to 3, or an integer of 0 to 2, stepwise, among which 0 or 1, particularly 0. In rings Z ^1a and Z ^1b , the types of groups R ^2a and R ^2b and the substitution numbers n2a and n2b may be the same or different. Furthermore, when the substitution numbers n2a and n2b are 2 or more, the types of two or more groups R ^2a and R ^2b substituting the same rings Z ^1a and Z ^1b may be the same or different. The substitution positions of the groups R ^2a and R ^2b are not particularly limited, as long as they are substituted at positions other than the bonding positions between the rings Z ^1a and Z ^1b and the hydroxyalkoxy groups [—O—A ^1a -OH] and [—O—A ^1b -OH] and the 9-position of the fluorene ring.

Examples of the linear or branched alkylene groups represented by groups A ^1a and A ^1b include linear or branched C _2-6 alkylene groups such as ethylene, propylene (1,2-propanediyl), trimethylene, 1,2-butanediyl, and tetramethylene. Preferred alkylene groups A ^1a and A ^1b are linear or branched C _2-4 alkylene groups, more preferably linear or branched C _2-3 alkylene groups such as ethylene and propylene, and particularly ethylene. The alkylene groups A ^1a and A ^1b may be different from each other, but are usually the same.

The substitution positions of the hydroxyalkoxy groups [—O-A ^1a -OH] and [—O-A ^1b -OH] are not particularly limited, as long as they are positions other than the bonding positions between rings Z ^1a and Z ^1b and the 9-position of the fluorene ring. For example, when rings Z ^1a and Z ^1b are naphthalene rings, the 1- or 2-position of the naphthalene ring is usually substituted with respect to the 9-position of the fluorene ring (substitution in a 1-naphthyl or 2-naphthyl relationship), and the hydroxyalkoxy groups are often substituted at any of the 5- to 8-positions relative to this substitution position. Preferably, the hydroxyalkoxy groups are substituted at the 1,5-positions or the 2,6-positions, and particularly preferably at the 2,6-positions. When rings ^Z1a and ^Z1b are biphenyl rings, the hydroxyalkoxy group may be substituted at any of the 2- to 6-positions or the 2'- to 6'-positions of the biphenyl ring, but for example, the 3- or 4-position of the biphenyl ring may be bonded to the 9-position of the fluorene ring, and when the 3-position of the biphenyl ring is bonded to the 9-position of the fluorene ring, the substitution position of the hydroxyalkoxy group may be, for example, any of the 2-, 4-, 5-, 6-, 2'-, 3'-, or 4'-positions of the biphenyl ring, preferably either the 6- or 4'-position, and particularly preferably the 6-position. When the 4-position of the biphenyl ring is bonded to the 9-position of the fluorene ring, the substitution position of the hydroxyalkoxy group may be any of the 2-, 3-, 2'-, 3'-, or 4'-positions of the biphenyl ring, preferably either the 2- or 4'-position, and particularly preferably the 2-position.

Representative examples of the fluorene compound represented by formula (1) include compounds having a structure symmetrical with respect to the 9-position of the fluorene ring in formula (1) (when the chemical formula is written on paper, it is line-symmetrical with respect to a vertical line passing through the 9-position of the fluorene ring), i.e., compounds in which Z ^1a and Z ^1b , R ^2a and R ^2b , n2a and n2b , and A ^1a and A ^1b are identical to one another, including the relationship between the substitution positions, and in which the type, number of substitutions, and substitution positions of the group R ¹ are the same on the two benzene rings forming the fluorene ring. More specific examples include 9,9-bis(hydroxyalkoxy-fused polycyclic aryl)fluorenes and 9,9-bis(hydroxyalkoxy-ring-assembled polycyclic aryl)fluorenes.

Examples of the 9,9-bis(hydroxyalkoxy-fused polycyclic aryl)fluorenes include 9,9-bis(hydroxy C _2-6 alkoxy-C _10-14 fused polycyclic aryl)fluorenes such as 9,9-bis(hydroxyalkoxynaphthyl)fluorene, and specific examples include 9,9-bis(hydroxy C 2-6 alkoxy-naphthyl)fluorenes such as 9,9-bis[6-(2-hydroxyethoxy)-2-naphthyl]fluorene (also referred to as BNEF), 9,9-bis[6-(2-hydroxypropoxy)-2-naphthyl]fluorene, and 9,9-bis[5-(2 _- hydroxyethoxy)-1-naphthyl]fluorene.

Examples of 9,9-bis(hydroxyalkoxy ring-assembled polycyclic aryl)fluorenes include 9,9-bis(hydroxy C _2-6 alkoxy-C _12-20 ring-assembled polycyclic aryl)fluorenes such as 9,9-bis(aryl-hydroxyalkoxyphenyl)fluorene, and specific examples include 9,9-bis(C _6-10 aryl-hydroxy C 2-6 alkoxyphenyl)fluorenes such as 9,9-bis[4-(2-hydroxyethoxy)-3-phenylphenyl]fluorene (also referred to as BOPPEF) and 9,9-bis[4-( _2- hydroxypropoxy)-3-phenylphenyl]fluorene.

Of these fluorene compounds, 9,9-bis(hydroxy _C2-4 alkoxy-naphthyl)fluorenes such as BNEF and 9,9-bis( _C6-10 aryl-hydroxy _C2-4 alkoxyphenyl)fluorenes such as BOPPEF are preferred. Of these, 9,9-bis(hydroxyalkoxy-fused polycyclic aryl)fluorenes are preferred because of their excellent heat resistance and ease of achieving a high refractive index, and 9,9-bis(hydroxy _C2-3 alkoxy-naphthyl)fluorenes such as BNEF are particularly preferred.

Note that the fluorene compound represented by formula (1) may contain a combination of two or more types, but is usually essentially a single compound.

The HPLC purity (unit: area %) of the fluorene compound represented by formula (1) can be selected from a range of 90% or higher, and may particularly be 95% or higher, for example, 97% or higher. Preferred ranges are 97.5% or higher, 98% or higher, 98.3% or higher, 98.5% or higher, and 99% or higher, in the following stepwise order. If the purity is too low, coloration may not be effectively suppressed. When used as a resin raw material, coloration of the resulting resin may not be suppressed, or it may be difficult to adjust the resin to the desired composition ratio. In this specification and claims, purity can be measured by the method described in the Examples below.

[Impurity components]
In the present invention, discoloration, particularly discoloration under high temperature conditions, is suppressed by adjusting the content of specific impurity components in the compound represented by formula (1) to a predetermined range. The impurity components may be components that are mixed in or produced as by-products during the production process of the compound represented by formula (1), or may be components that are intentionally added to the purified compound represented by formula (1). The content of impurity components is usually adjusted by the production method or purification of the compound represented by formula (1). Representative impurity components include compounds represented by formula (2) (fluorenones), compounds represented by formula (3) (aryloxy alcohols), sulfur components (sulfur-containing components), etc.

(Compound represented by formula (2) (first impurity component))

(wherein ^R3 represents a substituent, and n3 represents an integer of 0 to 8).

In the formula (2), the group ^R3 is, for example, the same as the substituents exemplified as the group ^R1 in the formula (1), including preferred embodiments.

The number of substitutions, ⁿ³ , of the group R3 is, for example, the same as the range exemplified for n1 in the formula (1), including preferred embodiments. When n3 is 2 or more, the types of the two or more groups ^R3 may be the same or different. Furthermore, in the two benzene rings forming the fluorene ring (fluorenone ring), the types and the number of substitutions of the groups ^R3 may be the same or different.

Typical compounds represented by formula (2) include 9-fluorenone. The compounds represented by formula (2) may be used alone or in combination of two or more.

The compound represented by the formula (2) is often left as an unreacted component of the raw material when preparing the compound represented by the formula (1), and therefore is often a compound in which the groups ^R3 and n3 correspond to the groups ^R1 and n1 of the formula (1).

The content of the compound represented by formula (2) is, for example, about 0.5% or less in terms of HPLC area percentage. Preferred ranges are 0.4% or less, 0.3% or less, 0.2% or less, 0.15% or less, 0.1% or less, 0.05% or less, and 0.03% or less, in the following stepwise order, and more preferably 0.02% or less, and particularly 0.01% or less. If the content of the compound represented by formula (2) is too high, discoloration may occur. In addition, when used as a resin raw material, the resulting resin may also be easily discolored, and heat resistance such as the glass transition temperature of the resin may decrease. Note that, in this specification and claims, "HPLC area percentage" can be measured by the method described in the Examples below.

(Compound represented by formula (3) (second impurity component))

(wherein ^Z2 represents an arene ring;
^R4 represents a substituent; n4 represents an integer of 0 or more;
^A2 represents a linear or branched alkylene group).

In the formula (3), ring ^Z2 may be, for example, a monocyclic arene ring such as a benzene ring, or a polycyclic arene ring. Polycyclic arene rings are the same as the arene rings exemplified as rings ^Z1a and ^Z1b in the section on formula (1), including preferred embodiments. Preferred ring ^Z2 is a C6-14 arene ring such as a benzene ring, a naphthalene ring, or a biphenyl ring, more preferably a _C6-12 arene ring, and among these, _{a C6-10} arene ring such as a benzene ring or a naphthalene ring is preferred, with a naphthalene ring being particularly preferred.

The substituent represented by ^R4 is, for example, the same as the groups exemplified as groups ^R2a and ^R2b in the section on formula (1), including preferred embodiments. The number of substitutions n4 is, for example, the same as the ranges exemplified as n2a and n2b in the section on formula (1), including preferred embodiments. When n4 is 2 or more, the types of the two or more groups ^R4 may be the same or different. In addition, the substitution position of group ^R4 is not particularly limited.

The alkylene group represented by ^A2 is the same as, for example, the groups exemplified as groups ^A1a and ^A1b in the section on formula (1), including preferred embodiments. The substitution position of the group [—O— ^A2 -OH] is not particularly limited.

Representative compounds represented by the formula (3) include phenoxy C _2-6 alcohols such as 2-phenoxyethanol; naphthoxy C _2-6 alcohols such as 2-(2-naphthoxy)ethanol and 2-(1-naphthoxy)ethanol; and biphenylyloxy C _2-6 alcohols such as 2-(o-phenylphenyloxy)ethanol.

The compound represented by formula (3) may be used alone or in combination of two or more. Among these compounds represented by formula (3), phenoxy C _2-4 alcohol, naphthoxy C 2-4 alcohol, and o-phenylphenyloxy C _2-4 alcohol such as 2-(o-phenylphenyloxy)ethanol are preferred, and phenoxy C _2-3 alcohol such as 2-phenoxyethanol, and 2-naphthoxy C _2-3 alcohol such _as 2-(2-naphthoxy)ethanol are more preferred.

The compound represented by the formula (3) may remain as an unreacted component of the raw material when preparing the compound represented by the formula (1), and therefore may be a compound in which ^Z2 corresponds to ^Z1a and ^Z1b in the formula (1), ^R4 corresponds to ^R2a and ^R2b in the formula (1), n4 corresponds to n2a and n2b in the formula (1), and ^A2 corresponds to ^A1a and ^A1b in the formula (1).

The content of the compound represented by formula (3) is, for example, about 3% or less in terms of area percentage by HPLC. Preferred ranges are 2% or less, 1% or less, 0.5% or less, 0.3% or less, 0.2% or less, 0.15% or less, 0.1% or less, 0.05% or less, and 0.03% or less, and more preferably 0.02% or less, and particularly 0.01% or less. If the content of the compound represented by formula (3) is too high, it may be prone to discoloration. It may also make the resin obtained when used as a resin raw material prone to discoloration, and it may act as a polymerization terminator, preventing the molecular weight of the resin from being sufficiently improved. Furthermore, if the compound represented by formula (1) is in powder form, it may have reduced fluidity, making it difficult to handle. On the other hand, if the content is too low, the compound represented by formula (1) in powder form may be prone to scattering, making it difficult to handle.

(Sulfur component (third impurity component))
The sulfur component is not particularly limited as long as it contains at least a sulfur atom in its chemical structure. In general, in the production of the compound represented by formula (1), an acid containing a sulfur atom, such as sulfuric acid, is often used as an acid catalyst, and a thiol is often used as a co-catalyst, as will be described later. Therefore, the sulfur component is contained in the compound represented by formula (1) as a result of the residue of these components or by-products generated by a side reaction of these components.

The sulfur component content (residual sulfur or total sulfur content) is, for example, approximately 100 ppm by mass or less, calculated as sulfur atoms, relative to the total amount of the compound represented by formula (1) and its impurities. Preferred ranges are as follows: 50 ppm by mass or less, 20 ppm by mass or less, 10 ppm by mass or less, 8 ppm by mass or less, 5 ppm by mass or less, 4 ppm by mass or less, 3 ppm by mass or less, and 2 ppm by mass or less. More preferably, the content is 1.8 ppm by mass or less, and even more preferably, 1.6 ppm by mass or less, with 1.5 ppm by mass or less, and particularly, 1.4 ppm by mass or less. Too much residual sulfur may result in discoloration of the resulting resin when used as a resin raw material, which may reduce the resin's heat resistance, such as its glass transition temperature. It may also lead to side reactions during polymerization, a slower polymerization rate, an increased amount of polymerization catalyst required, and corrosion of the reaction vessel. In contrast, in the present invention, the residual sulfur is adjusted to a low range, thereby effectively suppressing discoloration and improving heat resistance. In particular, when used as a raw material for polyester resins such as polycarbonate resins, the sulfur component content, calculated as sulfur atoms, is 1.8 mass ppm or less, preferably 1.7 mass ppm or less, more preferably 1.6 mass ppm or less, even more preferably 1.5 mass ppm or less, and particularly preferably 1.4 mass ppm or less, from the viewpoint of further improving heat resistance. Reducing the sulfur component content to this range appears to enable even greater improvement in heat resistance, even if the material contains a relatively large amount of impurities that may reduce heat resistance, such as the first impurity component represented by the aforementioned formula (2). In this specification and claims, residual sulfur can be measured by the method described in the Examples below.

(Other impurities)
The compound represented by formula (1) may or may not contain other impurity components different from the first to third impurity components. The other impurity components may be impurities that may be mixed in during the production and/or purification of the compound represented by formula (1), or may be impurities that are intentionally added in trace amounts. Representative other impurity components (a) to (j) will be described below.

(a) Compounds Represented by Formula (4) Compounds represented by the following formula (4) include compounds in which at least one of the hydroxyalkoxy groups [-O-A ^1a -OH] and [-O-A ^1b -OH] in the compound represented by formula (1) is replaced with a hydroxyl group or two or more alkylene oxide (alkylene carbonate or haloalkanol) adducts (or multi-adducts) thereof; and compounds in which a monocyclic arene ring such as a benzene ring is bonded to the 9-position of the fluorene ring (as rings Z ^3a and Z ^3b ) in a 9,9-bisarylfluorene skeleton.

(In the formula, ^Z3a and ^Z3b each independently represent an arene ring,
^R5 represents a substituent; n5 represents an integer of 0 to 8;
R ^6a and R ^6b each independently represent a substituent; n6a and n6b each independently represent an integer of 0 or more;
^A3a and ^A3b each independently represent a linear or branched alkylene group, and m3a and m3b each independently represent an integer of 0 or greater, provided that when both ^Z3a and ^Z3b are polycyclic arene rings, m3a and m3b cannot simultaneously be 1.

In the formula (4), Z ^3a and Z ^3b can be monocyclic arene rings such as a benzene ring, or polycyclic arene rings. Examples of polycyclic arene rings include the same as the rings exemplified as Z ^1a and Z ^1b in the formula (1), including preferred embodiments. Preferred Z ^3a and Z ^3b are C _6-14 arene rings such as a benzene ring, a naphthalene ring, or a biphenyl ring, and more preferably C _6-12 arene rings. Of these, C _6-10 arene rings such as a benzene ring or a naphthalene ring are preferred, and a naphthalene ring is particularly preferred. Note that Z ^3a and Z ^3b may be different from each other, but are usually the same in most cases.

The substituent represented by ^R5 and the number of substitutions n5 are the same as those of ^R1 and n1 in the formula (1), including preferred embodiments. In addition, preferred embodiments such as the type and substitution position of two or more ^R5s are also the same as those of ^R1 and n1 in the formula (1).

The substituents represented by ^R6a and ^R6b and the number of substitutions n6a and n6b are the same as those of ^R2a and R2b and n2a and ^n2b in formula (1), including preferred embodiments. In addition, preferred embodiments such as the type and substitution position of two or more ^R6a and ^R6b are also the same as those of R2a and ^R2b and n2a and ^n2b in formula (1).

The alkylene groups represented by A ^3a and A ^3b are the same as those represented by A ^1a and A ^1b in the formula (1), including preferred embodiments thereof.

The repeat numbers m3a and m3b are each, for example, 0 to 10, and preferred ranges are, in the following stepwise order, 0 to 6, 0 to 4, and 0 to 3, more preferably 0 to 2, and particularly preferably 0 to 1. m3a and m3b may be the same as each other, but are often different. When the repeat numbers m3a and m3b are 2 or more, the types of the two or more A ^3a and A ^3b may be different from each other, but are usually often the same.

When Z ^3a and Z ^3b are benzene rings, the substitution positions of the groups [-(O-A ^3a ) _m3a -OH] and [-(O-A ^3b ) _m3b -OH] are the 2nd to 4th positions, preferably the 3rd or 4th position, and more preferably the 4th position, relative to the phenyl group substituted at the 9th position of the fluorene ring. When Z ^3a and Z ^3b are naphthalene rings or biphenyl rings, the same applies, including preferred embodiments, to the substitution positions of the hydroxyalkoxy groups [-O-A ^1a -OH] and [-O-A ^1b -OH] relative to Z ^1a and Z ^1b in the formula (1), respectively.

Representative compounds represented by the formula (4) include: (i) a compound in which Z ^3a and Z ^3b are arene rings such as a benzene ring, a naphthalene ring, or a biphenyl ring, and m3a and m3b are 0 (9,9-bis(hydroxyaryl)fluorenes or alkylene oxide-free adducts); (ii) a compound in which Z ^3a and Z ^3b are arene rings such as a benzene ring, a naphthalene ring, or a biphenyl ring, and one of m3a and m3b is 0 and the other is 1 (alkylene oxide 1-adducts); (iii) a compound in which Z ^3a and Z ^3b are arene rings such as a benzene ring, a naphthalene ring, or a biphenyl ring, and one of m3a and m3b is 1 and the other is 2 (alkylene oxide 3-adducts); and (iv) a compound in which Z ^3a and Z ^3b are benzene rings, and m3a and m3b are 1 (9,9-bis(hydroxyalkoxyphenyl)fluorenes).

Specific examples of the 9,9-bis(hydroxyaryl)fluorenes of (i) above include 9,9-bis(hydroxyphenyl)fluorenes such as 9,9-bis(4-hydroxyphenyl)fluorene; 9,9-bis(alkyl-hydroxyphenyl)fluorenes, for example, 9,9-bis(mono- or di-C _1-6 alkyl-hydroxyphenyl)fluorenes such as 9,9-bis(3-methyl-4-hydroxyphenyl)fluorene and 9,9-bis(3,5-dimethyl-4-hydroxyphenyl)fluorene; 9,9-bis(aryl-hydroxyphenyl)fluorenes, for example, 9,9-bis(C _6-10 aryl-hydroxyphenyl)fluorenes such as 9,9-bis(3-phenyl-4-hydroxyphenyl)fluorene; and 9,9-bis(hydroxynaphthyl)fluorenes such as 9,9-bis(6-hydroxy-2-naphthyl)fluorene and 9,9-bis(5-hydroxy-1-naphthyl)fluorene.

Specific examples of the alkylene oxide monoadduct (ii) include the following compounds:

Specific examples of the alkylene oxide triadduct (iii) include the following compounds.

Specific examples of the 9,9-bis(hydroxyalkoxyphenyl)fluorenes of (iv) above include 9,9-bis(hydroxyC 2-6 alkoxyphenyl)fluorenes such as 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene, 9,9-bis[4-(2-hydroxypropoxy)phenyl]fluorene, 9,9-bis[4-(2-hydroxyethoxy)-3-methylphenyl]fluorene, and 9,9-bis[4-( _2- hydroxyethoxy)-3,5-dimethylphenyl]fluorene, or 9,9-bis(mono- or di-C _1-6 alkyl-hydroxyC _2-6 alkoxyphenyl)fluorene.

These compounds may be contained alone or in combination of two or more. These compounds represented by formula (4), particularly compounds in which ^Z3a and ^Z3b are polycyclic arene rings such as naphthalene rings or biphenyl rings, often remain as unreacted components or by-products when a method is adopted in which alkylene oxides (alkylene carbonates or haloalkanols) are added to 9,9-bis(hydroxypolycyclic aryl)fluorenes obtained by reacting fluorenones with polycyclic phenols in the production of the compound represented by formula (1).

The content of the compound represented by formula (4) is, for example, about 10% or less, as measured by HPLC area ratio, and can be selected from the range of 0.1 to 10%, preferably 7.5% or less, 5% or less, 3% or less, 1% or less, 0.3% or less, 0.1% or less, 0.05% or less, more preferably 0.01% or less, particularly 0.005% or less, and particularly substantially 0% or below the detection limit. If the content of the compound represented by formula (4) is too high, particularly if there is too much of a compound having a phenolic hydroxyl group as in (i) and (ii), coloration may not be effectively suppressed due to susceptibility to oxidation, etc., and there may be a risk of deactivating the polymerization catalyst when used as a resin raw material, and the moldability (or melt fluidity) of the resulting resin may be reduced. Furthermore, if there is too much of an adduct to which multiple alkylene oxides are added, particularly as in (iii), there may be a risk of reduced heat resistance, water resistance, and/or impact strength of the resin. Furthermore, if the amount of the compound in which ^Z3a and ^Z3b are benzene rings is too large, the heat resistance and refractive index of the resin may decrease. Note that, if the alkylene oxide triadduct (iii) is contained, the moldability (melt fluidity) and/or tensile strength of the resin may be improved.

On the other hand, even if the alkylene oxide tri-adduct (iii) is contained, so long as the content of the compound represented by formula (4) is 5% or less, for example, 0.1 to 5%, preferably 0.2 to 4%, more preferably 0.3 to 3%, and even more preferably 0.5 to 2%, in terms of HPLC area percentage, the properties will not be significantly impaired. In particular, by combining it with the alkylene oxide mono-adduct (ii), heat resistance may be improved.

In other words, containing the alkylene oxide mono-adduct (ii) in a predetermined proportion may improve heat resistance while suppressing discoloration in the resin. Therefore, the content of the alkylene oxide mono-adduct (ii) may be, for example, 0.01 to 2%, particularly 0.01 to 1%, in terms of HPLC area percentage, and preferably the following stepwise ranges: 0.05 to 2%, 0.1 to 2%, 0.2 to 1.5%, 0.3 to 1%, 0.4 to 0.9%, 0.45 to 0.85%, 0.5 to 0.8%, and 0.6 to 0.75%. Containing the alkylene oxide mono-adduct (ii) in such a proportion may effectively improve heat resistance while suppressing discoloration in polyester resins, preferably polycarbonate resins and polyester-polycarbonate copolymers, and more preferably polycarbonate resins. In particular, when the content of the compound represented by formula (2) (first impurity component) and the sulfur component (third impurity component) is low, containing the alkylene oxide monoadduct (ii) in a specific proportion appears to further improve heat resistance.

The content of the alkylene oxide triadduct (iii) may be, for example, about 0.01 to 5% in terms of HPLC area percentage, with preferred ranges being 0.05 to 5%, 0.1 to 5%, 0.5 to 4.5%, 1 to 4%, 1.1 to 3%, 1.2 to 2%, and 1.3 to 1.5%, in the following stepwise order.

(b) Multimers Comprising Multiple 9,9-bisarylfluorene Skeletons The compound represented by formula (1) may or may not contain multimers comprising multiple 9,9-bisarylfluorene skeletons. A multimer comprising multiple 9,9-bisarylfluorene skeletons has a chemical structure in which one arene ring is bonded to the 9-positions of at least two fluorene rings, and is typically a compound represented by formula (5) below.

(wherein Z ^4a to Z ^4d each independently represent an arene ring;
R ^7a to R ^7c each independently represent a substituent; n7a to n7c each independently represent an integer of 0 to 8;
R ^8a to R ^8d each independently represent a substituent, and n8a to n8d each independently represent an integer of 0 or more;
A ^4a to A ^4d each independently represent a linear or branched alkylene group, m4a to m4d each independently represent an integer of 0 or more,
k represents an integer of 0 or more).

In the formula (5), the arene rings Z ^4a to Z ^4d are the same as those of Z ^3a and Z ^3b in the formula (4), including preferred embodiments. Z ^4a to Z ^4d may be different from one another, but are usually the same.

R ^7a to R ^7c and n7a to n7c are the same as R ¹ and n1 in formula (1), including preferred embodiments. Preferred embodiments, such as the types and substitution positions of two or more R ^7a to R ^7c , are also the same as those of R ¹ and n1 in formula (1). R ^7a to R ^7c and n7a to n7c may be the same or different from each other.

R ^8a to R ^8d and n8a to n8d are the same as R ^2a and R ^2b and n2a and n2b in formula (1), including preferred embodiments. Furthermore, preferred embodiments such as the types and substitution positions of two or more R ^8a to R ^8d are also the same as those of R ^2a and R ^2b and n2a and n2b in formula (1). R ^8a to R ^8d and n8a to n8d may be the same or different from each other.

A ^4a to A ^4d are the same as A ^3a and A ^3b in formula (3), including preferred embodiments. Furthermore, preferred embodiments such as the type and substitution position of two or more A ^4a to A ^4d are also the same as those for A ^3a and A ^3b in formula (3). Examples of m4a to m4d include the same ranges as those for m3a and m3b in formula (3), and m4a to m4d is preferably 1. Unlike m3a and m3b, all of m4a to m4d may be 1. Furthermore, A ^4a to A ^4d and m4a to m4d may be the same or different from each other.

The number of repetitions k may be, for example, about 0 to 10, and preferred ranges are, in the following stepwise order, 0 to 8, 0 to 5, 0 to 3, and 0 to 2, and more preferably 0 or 1. When k is 2 or more, two or more of Z ^4c , R ^7b , n7b, R ^8c , n8c, A ^4c , and m4c may be the same or different from each other.

Representative compounds represented by formula (5) include compounds in which Z ^4a to Z ^4d are benzene rings, naphthalene rings or biphenyl rings, A ^4a to A ^4d are linear or branched C _2-4 alkylene groups, m4a to m4d are integers of 0 to 2, and k is 0 or 1. Preferred compounds are compounds in which Z ^4a to Z ^4d are naphthalene rings, A ^4a to A ^4d are linear or branched C _2-3 alkylene groups, m4a to m4d are 1, and k is 0 or 1.

The content of the multimer containing multiple 9,9-bisarylfluorene structures may be, for example, approximately 0.02 to 4% in terms of area percentage by HPLC, with preferred ranges being 0.02 to 3%, 0.02 to 2%, 0.02 to 1%, 0.02 to 0.8%, and 0.02 to 0.6%, in the following stepwise order. The inclusion of such a multimer may suppress coloration in the resin, improve moldability (melt fluidity), and improve resin strength uniformly or stably. Furthermore, when the compound represented by formula (1) is in powder form, the powder's fluidity or handleability may be improved. If the proportion of such a multimer is too high, gelation may occur during polymerization.

(c) Compound Represented by Formula (6) The compound represented by formula (1) may or may not contain a compound represented by the following formula (6).

(wherein Z ^5a to Z ^5c each independently represent an arene ring;
^R9 represents a substituent; n9 represents an integer of 0 to 8;
R ^10a to R ^10c each independently represent a substituent; n10a to n10c each independently represent an integer of 0 or more;
A ^5a to A ^5c each independently represent a linear or branched alkylene group, and m5a to m5c each independently represent an integer of 0 or more).

In the formula (6), Z ^5a to Z ^5c are the same as Z ^3a and Z ^3b in the formula (4), including preferred embodiments. Z ^5a to Z ^5c may be different from one another, but are usually the same.

The substituents represented by ^R9 and the number of substitutions n9 are the same as those of ^R1 and n1 in the formula (1), including preferred embodiments. In addition, preferred embodiments such as the type and substitution position of two or more ^R9s are also the same as those of ^R1 and n1 in the formula (1).

The substituents R ^10a to R ^10c and the number of substitutions n10a to n10c are the same as those of R ^2a and R ^2b and n2a and n2b in the formula (1), including preferred embodiments. Furthermore, preferred embodiments such as the types and substitution positions of two or more R ^10a and R ^10b are the same as those corresponding to R ^2a and R ^2b and n2a and n2b in the formula (1). When n10c is two or more, the types of the two or more R ^10c may be the same or different from each other. The substitution position of R ^10c is not particularly limited. Furthermore, R ^10a to R ^10c and n10a to n10c may be the same or different from each other.

The alkylene groups A ^5a to A ^5c are the same as A ^3a and A ^3b in formula (4), including preferred embodiments. Examples of m5a to m5c include the same ranges as m3a and m3b in formula (4), and are preferably 1. Unlike m3a and m3b, all of m5a to m5c may be 1. Preferred embodiments, such as the types of two or more A ^5a and A ^5b and the substitution positions for Z ^5a and Z ^5b substituted via an oxygen atom, are the same as those for A ^3a and A ^3b in formula (4). When m5c is two or more, the types of two or more A ^5c may be the same or different from each other. The substitution position for Z ^5c substituted via an oxygen atom by A ^5c is not particularly limited. A ^5a to A ^5c and m5a to m5c may be the same or different from each other.

Representative compounds represented by formula (6) include compounds in which Z ^5a to Z ^5c are benzene rings, naphthalene rings or biphenyl rings, A ^5a to A ^5c are linear or branched C _2-4 alkylene groups, and m5a to m5c are integers of 1 or 2. Preferred compounds are compounds in which Z ^5a to Z ^5c are naphthalene rings, A ^5a to A ^5c are linear or branched C _2-3 alkylene groups, and m5a to m5c are 1.

The content of the compound represented by formula (6) may be, for example, approximately 0.02 to 4% in terms of HPLC area percentage, with preferred ranges being 0.05 to 3%, 0.08 to 2%, 0.1 to 1%, 0.15 to 1%, 0.2 to 1%, 0.25 to 0.8%, and 0.3 to 0.4%, in the following stepwise order. The inclusion of the compound represented by formula (6) may improve the moldability (melt fluidity) and/or tensile strength of the resin. If the proportion of the compound represented by formula (6) is too high, it may act as a polymerization terminator, preventing the molecular weight of the resin from being sufficiently increased.

(d) Compound Having a 9,9-bis(alkylthio)fluorene Skeleton The compound represented by formula (1) may or may not contain a compound having a 9,9-bis(alkylthio)fluorene skeleton. Examples of compounds having a 9,9-bis(alkylthio)fluorene skeleton include compounds represented by formula (7) below. The compound represented by formula (7) may be, for example, a by-product generated in the reaction of a raw material fluorenone with a thiol such as β-mercaptopropionic acid, which is often used as a co-catalyst, in the preparation of the compound represented by formula (1), particularly in the reaction when an excess of thiol is added.

(wherein R ¹¹ represents a substituent, n11 represents an integer of 0 to 8,
R ^12a and R ^12b each independently represent a monovalent to trivalent hydrocarbon group;
X ^1a and X ^1b each independently represent a heteroatom-containing group, and p1a and p1b each independently represent an integer of 0 to 2).

In the formula (7), the substituent represented by ^R11 and the number of substitutions n11 are the same as those of ^R1 and n1 in the formula (1), including preferred embodiments. In addition, preferred embodiments such as the type and substitution position of two or more ^R11 are also the same as those of ^R1 and n1 in the formula (1).

Examples of the monovalent hydrocarbon groups represented by R ^12a and R ^12b include the hydrocarbon groups exemplified as R ^2a and R ^2b in formula (1) above, and hydrocarbon groups formed by combining a plurality of these groups. Examples of the divalent or trivalent hydrocarbon groups represented by R ^12a and R ^12b include groups obtained by removing a hydrogen atom from the monovalent hydrocarbon groups described above depending on the valence.

R ^12a and R ^12b are preferably divalent hydrocarbon groups, more preferably linear or branched alkylene groups. Examples of the linear or branched alkylene group include the alkylene groups exemplified as A ^1a and A ^1b in formula (1), and the same applies to them, including preferred embodiments.

In the heteroatom-containing group represented by X ^1a and X ^1b , examples of the heteroatom include a nitrogen atom, an oxygen atom, and a sulfur atom, preferably a nitrogen atom or an oxygen atom, and more preferably an oxygen atom. The number of heteroatoms contained is not particularly limited and is usually 1 to 3, preferably 1 to 2.

Representative heteroatom-containing groups include amino groups; mono- or di-substituted amino groups such as dialkylamino groups and diacylamino groups; hydroxyl groups; carboxyl groups; alkoxycarbonyl groups such as methoxycarbonyl groups. Preferred X ^1a and X ^1b are amino groups and carboxyl groups, and more preferably carboxyl groups. X ^1a and X ^1b may be different from each other, but are usually the same in most cases.

The substitution numbers p1a and p1b may be selected depending on the valence of R ^12a and R ^12b , and are, for example, 0 to 1, preferably 1. When p1a and p1b are 2, the types of the two X ^1a and X ^1b may be the same or different.

Representative compounds represented by formula (7) include 9,9-bis(carboxyalkylthio)fluorenes, for example, 9,9-bis(carboxyC _1-6 alkylthio)fluorenes such as 9,9-bis(carboxymethylthio)fluorene and 9,9-bis(2-carboxyethylthio)fluorene; 9,9-bis(aminoalkylthio)fluorenes, for example, 9,9-bis(aminoethylthio)fluorene, for example, 9,9-bis(aminoC _1-6 alkylthio)fluorenes; 9,9-bis(alkylthio)fluorenes, for example, 9,9-bis(C _1-12 alkylthio)fluorenes such as 9,9-bis(ethylthio)fluorene; and the like.

The compound represented by formula (7) may be contained alone or in combination of two or more kinds. Among the compounds represented by formula (7), 9,9-bis(carboxyalkylthio)fluorenes, particularly 9,9-bis(carboxyC _1-4 alkylthio)fluorenes such as 9,9-bis(2-carboxyethylthio)fluorene, are often used.

The content of the compound represented by formula (7) may be, for example, about 0.5% or less in terms of HPLC area percentage, with preferred ranges being 0.3% or less, 0.1% or less, 0.05% or less, 0.03% or less, and 0.01% or less, in the following stepwise order. If the proportion of the compound represented by formula (7) is too high, it may cause discoloration and, when used as a resin raw material, may make it difficult for polymerization to proceed or may reduce the heat resistance of the resin.

(e) Compound Represented by Formula (8) The compound represented by formula (1) may or may not contain a compound represented by the following formula (8): The compound represented by formula (8) may be, for example, a by-product produced in the reaction of a raw material phenol or aryloxy alcohol with a thiol that is often used as a co-catalyst in the preparation of the compound represented by formula (1).

(wherein ^Z6 represents an arene ring;
^A6 represents a linear or branched alkylene group, m6 represents an integer of 0 or more,
^R13 represents a substituent; n13 represents an integer of 0 or more;
R ¹⁴ represents a monovalent to trivalent hydrocarbon group;
^X2 represents a heteroatom-containing group, and p2 represents an integer of 0 to 2).

In the formula (8), ^Z6 is the same as ^Z3a and ^Z3b in the formula (4), including preferred embodiments.

^A6 is, for example, the same as ^A3a and ^A3b in formula (4), including preferred embodiments. The number of repeats m6 is the same as m3a and m3b in formula (4), including preferred embodiments. The substitution position of the group [-(O- ^A6 ) _m6 -OH] is not particularly limited.

The substituent ^R13 and the number of substitutions n13 are the same as ^R2a and ^R2b , and n2a and n2b in formula (1), including preferred embodiments. When n13 is 2 or more, the types of the two or more ^R13 may be the same or different.

R ¹⁴ is the same as R ^12a and R ^12b in the formula (7), including preferred embodiments.

The heteroatom-containing group ^X2 is the same as ^X1a and ^X1b in formula (7), including preferred embodiments. The number of substitutions p2 is usually 0 to 1, and may be 0 or 1. The substitution position of the group [—S—R ¹⁴ —(X ² ) _p2 ] is not particularly limited.

Representative compounds represented by the formula (8) include those in which ^Z6 is a benzene ring, a naphthalene ring, or a biphenyl ring, ^A6 is a linear or branched _C2-6 alkylene group, m6 is an integer of 0 to 2, ^R14 is a _C1-20 alkyl group or a linear or branched _C2-6 alkylene group, ^X2 is a carboxyl group or an amino group, and p2 is 0 or 1. Preferred compounds represented by the formula (8) are those in which ^Z6 is a naphthalene ring, ^A6 is a linear or branched _C2-4 alkylene group, m6 is 0 or 1, ^R14 is a _C1-16 alkyl group or a linear or branched _C2-4 alkylene group, ^X2 is a carboxyl group or an amino group, and p2 is 0 or 1.

The content of the compound represented by formula (8) may be, for example, approximately 0.1 ppb to 1% by mass, with preferred ranges being 0.5 ppb to 5000 ppm by mass, 1 ppb to 3000 ppm by mass, and 10 ppb to 1000 ppm by mass, in the following stepwise order. The inclusion of the compound represented by formula (8) may help to suppress discoloration in high-temperature environments. If the proportion of the compound represented by formula (8) is too high, it may be difficult to adjust the desired resin composition ratio, and discoloration may not be suppressed.

(f) Compound Represented by Formula (9) The compound represented by formula (1) may or may not contain a compound represented by the following formula (9): The compound represented by formula (9) may be, for example, a by-product generated in a side reaction of thiols that are often used as co-catalysts in the preparation of the compound represented by formula (1).

(In the formula, R ^15a and R ^15b each independently represent a monovalent to trivalent hydrocarbon group,
^X3a and ^X3b each independently represent a heteroatom-containing group, and p3a and p3b each independently represent an integer of 0 to 2).

In the formula (9), R ^15a and R ^15b are the same as R ^12a and R ^12b in the formula (7), including preferred embodiments. R ^15a and R ^15b may be different from each other, but are usually the same.

^X3a and ^X3b are the same as ^X1a and ^X1b in formula (7), including preferred embodiments. The number of substitutions p3a and p3b is usually 0 to 1, and may be 0 or 1. The types of ^X3a and ^X3b may be the same or different. When p3a and p3b are 2, the types of the two ^X3a and ^X3b may be the same or different.

Representative compounds represented by the formula (9) include compounds in which R ^15a and R ^15b are a C _1-20 alkyl group or a linear or branched C _2-6 alkylene group, X ^3a and X ^3b are a carboxyl group or an amino group, and p3a and p3b are 0 or 1. Preferred compounds represented by the formula (9) include compounds in which R ^15a and R ^15b are a C _1-16 alkyl group or a linear or branched C _2-4 alkylene group, X ^3a and X ^3b are a carboxyl group or an amino group, and p3a and p3b are 0 or 1.

The content of the compound represented by formula (9) may be, for example, approximately 0.1 ppb to 1% by mass, with preferred ranges being 0.5 ppb to 5000 ppm by mass, 1 ppb to 3000 ppm by mass, and 10 ppb to 1000 ppm by mass, in the following stepwise order. The inclusion of the compound represented by formula (9) may help to suppress discoloration in high-temperature environments. If the proportion of the compound represented by formula (9) is too high, it may be difficult to adjust the desired resin composition ratio, and discoloration may not be suppressed.

(g) Compound represented by formula (10) or salt thereof The compound represented by formula (1) may or may not contain a compound represented by the following formula (10) or a salt thereof. The compound represented by formula (10) or a salt thereof may be, for example, a by-product generated in a side reaction between a raw material phenol or aryloxy alcohol and an acid catalyst such as sulfuric acid in the preparation of the compound represented by formula (1).

(wherein ^Z7 represents an arene ring;
^A7 represents a linear or branched alkylene group, m7 represents an integer of 0 or more,
R ¹⁶ represents a substituent, and n16 represents an integer of 0 or more).

In the formula (10), Z ⁷ is the same as Z ^3a and Z ^3b in the formula (4), including preferred embodiments.

^A7 is, for example, the same as ^A3a and ^A3b in formula (4), including preferred embodiments. The repeat number m6 is the same as m3a and m3b in formula (4), including preferred embodiments. The substitution position of the group [-(O- ^A7 ) _m7 -OH] is not particularly limited.

The substituent ^R16 and the number of substitutions n16 are the same as ^R2a and ^R2b , and n2a and n2b in formula (1), including preferred embodiments. When n16 is 2 or more, the types of the two or more ^R16 may be the same or different.

In the formula (10), the substitution position of the sulfo group (or sulfonic acid group) [—SO ₃ H] is not particularly limited.

Salts of the compound represented by formula (10) include alkali metal salts such as lithium salt, sodium salt, and potassium salt, and ammonium salt. Of these, sodium salt or potassium salt is usually used, with sodium salt being preferred. The compound represented by formula (10) is preferably in the form of a salt.

Representative compounds represented by the formula (10) include compounds in which ^Z7 is a benzene ring, a naphthalene ring, or a biphenyl ring, ^A7 is a linear or branched _C2-6 alkylene group, and m7 is an integer of 0 to 2, and salts thereof, such as alkali metal salts. Preferred compounds represented by the formula (10) are compounds in which ^Z7 is a naphthalene ring, ^A7 is a linear or branched _C2-4 alkylene group, and m7 is an integer of 0 or 1, or sodium salts or potassium salts thereof.

The content of the compound represented by formula (10) or its salt may be, for example, approximately 0.1 ppb by mass to 1% by mass, with preferred ranges being 1 ppb by mass to 1000 ppm by mass, 5 ppb by mass to 100 ppm by mass, 8 ppb by mass to 80 ppm by mass, and 10 ppb by mass to 50 ppm by mass, in the following stepwise order. The inclusion of the compound represented by formula (10) or its salt may enable efficient resin polymerization and may prevent resin discoloration. If the proportion of the compound represented by formula (10) or its salt is too high, it may be difficult to adjust the desired resin composition ratio, and discoloration may not be prevented.

(h) Compound Represented by Formula (11) The compound represented by formula (1) may or may not contain a compound represented by the following formula (11).

(In the formula, Z ^8a and Z ^8b each independently represent an arene ring,
R ¹⁷ represents a substituent; n17 represents an integer of 0 to 8;
R ^18a and R ^18b each independently represent a substituent; n18a and n18b each independently represent an integer of 0 or more;
A ^8a to A ^8d each independently represent a linear or branched alkylene group, m8a and m8b each independently represent an integer of 0 or more, and m8c and m8d each independently represent an integer of 0 to 2, provided that m8c and m8d are not both 0.

In the formula (11), Z ^8a and Z ^8b are the same as Z ^3a and Z ^3b in the formula (4), including preferred embodiments. Z ^8a and Z ^8b may be different from each other, but are usually the same.

The substituent represented by ^R17 and the number of substitutions n17 are the same as those of ^R1 and n1 in the formula (1), including preferred embodiments. In addition, preferred embodiments such as the type and substitution position of two or more ^R17s are also the same as those of ^R1 and n1 in the formula (1).

The substituents R ^18a and R ^18b and the number of substitutions n18a and n18b are the same as R ^2a and R ^2b and n2a and n2b in formula (1), including preferred embodiments. In addition, preferred embodiments such as the types and substitution positions of two or more R ^18a and R ^18b are the same as those corresponding to R ^2a and R ^2b and n2a and n2b in formula (1).

The alkylene groups A ^8a to A ^8d are the same as A ^3a and A ^3b in the formula (4), including preferred embodiments.

Examples of m8a and m8b include the same ranges as those of m3a and m3b in the formula (4), and are preferably 1. Note that, unlike m3a and m3b, both m8a and m8b may be 1. Furthermore, preferred embodiments, such as the type of A ^8a and A ^8b when there are two or more, and the substitution positions of Z ^8a and Z ^8b substituted via an oxygen atom, are the same as those corresponding to A ^3a and A ^3b in the formula (4).

The number of substitutions m8c and m8d of the group (-A ^8c -OH) and the group (-A ^8d -OH) is 0 to 2, and preferably 0 or 1. m8c and m8d may be the same as or different from each other. The total of m8c and m8d is, for example, 1 to 4, preferably 1 to 3, further preferably 1 to 2, and even more preferably 1. The types of A ^8c and A ^8d may be different from each other, but are usually often the same.

When ring Z ^8a and ring Z ^8b are benzene rings, the substitution positions of the group (-A ^8c -OH) and the group (-A ^8d -OH) are the 2- to 4-positions, preferably the 3- or 4-position, and more preferably the 3-position, relative to the phenyl group substituting at the 9-position of the fluorene ring. When ring Z ^8a and ring Z ^8b are naphthalene rings, the substitution usually occurs at the 1- or 2-position of the naphthalene ring relative to the 9-position of the fluorene ring (substitution in a 1-naphthyl or 2-naphthyl relationship), and the substitution occurs at any of the 5- to 8-positions relative to this substitution position, preferably the group (-A ^8c -OH) and the group (-A ^8d -OH) are substituted at the 1,6- or 2,7-positions, particularly preferably the 2,7-positions. When ring Z ^8a and ring Z ^8b are biphenyl rings, the group (-A ^8c -OH) and the group (-A ^8d -OH) may be substituted at any of the 2- to 6-positions and the 2'- to 6'-positions of the biphenyl ring.

Representative compounds represented by formula (11) include those in which Z ^8a and Z ^8b are benzene rings, naphthalene rings or biphenyl rings, A ^8a to A ^8d are linear or branched C _2-4 alkylene groups, m8a and m8b are integers of 1 or 2, m8c and m8d are 0 or 1, and m8c and m8d are not simultaneously 0. Preferred compounds are those in which Z ^8a and Z ^8b are naphthalene rings, A ^8a to A ^8c are linear or branched C _2-3 alkylene groups, m8a and m8b are 1, m8c is 1, and m8d is 0.

The content of the compound represented by formula (11) is, for example, about 10% or less, in terms of HPLC area percentage, preferably 7.5% or less, 5% or less, 4% or less, 3% or less, 1% or less, 0.5% or less, 0.1% or less, more preferably 0.01% or less, particularly 0.005% or less, and particularly substantially 0% or below the detection limit. In particular, if the content of the compound represented by formula (11) is 3.5% or less, the resin can be prevented from decreasing in heat resistance, water resistance, impact strength, and refractive index, resulting in a resin raw material with an excellent balance of properties. If the content of the compound represented by formula (11) is too high, gelation may occur during polymerization.

Furthermore, when a compound represented by formula (11) is contained in a predetermined proportion, the molecular weight of the resin can be increased, and in particular, when a compound represented by formula (11) in which Z ^8a and Z ^8b are naphthalene rings, A ^8a to A ^8c are linear or branched C _2-3 alkylene groups, m8a and m8b are 1, m8c is 1, and m8d is 0 is contained in a predetermined proportion, the molecular weight of the polyester resin can be increased, and in particular, the molecular weight of the polyester resin can be significantly increased. The content of the compound represented by formula (11) is, for example, 0.1 to 10%, and preferred ranges are 0.5 to 7%, 1 to 6%, 1.2 to 5.5%, 1.5 to 5%, 2 to 4.5%, 2.5 to 4%, and 3 to 3.5%, in the following stepwise order. The content of the compound represented by formula (11) may be the content of a compound in which, in formula (11), Z ^8a and Z ^8b are naphthalene rings, A ^8a to A ^8c are linear or branched C _2-3 alkylene groups, m8a and m8b are 1, m8c is 1, and m8d is 0.

(i) Organic Solvent The compound represented by formula (1) may or may not contain an organic solvent that may be mixed in during the manufacturing process, such as preparation or purification. The organic solvent may be a conventional organic solvent that is in a liquid state at 25°C and 1 atmosphere, and examples thereof include hydrocarbons, halogenated hydrocarbons, alcohols, ethers, glycol ethers, glycol ether acetates, ketones, carboxylic acids, esters, carbonates, amides, ureas, nitriles, nitrated hydrocarbons, phosphoramides, sulfones, and sulfoxides.

Examples of hydrocarbons include aliphatic hydrocarbons such as hexane and dodecane, alicyclic hydrocarbons such as cyclohexane, and aromatic hydrocarbons such as toluene and xylene.

Examples of halogenated hydrocarbons include dichloromethane, chloroform, 1,2-dichloroethane, chlorobenzene, and dichlorobenzene.

Examples of alcohols include C _1-6 alcohols such as methanol, ethanol, propanol, isopropanol, n-butanol, isobutanol, s-butanol, and t-butanol.

Examples of ethers include chain ethers and cyclic ethers. Examples of chain ethers include di-C _1-6 alkyl ethers such as diethyl ether, diisopropyl ether, and dibutyl ether. Examples of cyclic ethers include 5- to 7-membered ring ethers such as tetrahydrofuran (THF), 2-methyltetrahydrofuran, tetrahydropyran, 4-methyltetrahydropyran, 1,4-dioxane, 1,3-dioxane, 4-methyl-1,3-dioxane, 1,3-dioxolane, and 2-methyl-1,3-dioxolane.

Examples of glycol ethers include (poly)alkylene glycol monoalkyl ethers and (poly)alkylene glycol dialkyl ethers. Examples of (poly)alkylene glycol monoalkyl ethers include cellosolves such as methyl cellosolve and ethyl cellosolve, carbitols such as methyl carbitol and ethyl carbitol, and (mono to hexa)C2-4 alkylene glycol mono _-C1-6 alkyl ethers such as triethylene glycol monomethyl ether, propylene glycol monomethyl ether, and dipropylene glycol monomethyl ether. Examples of (poly)alkylene glycol dialkyl ethers include (mono to hexa) _C2-4 alkylene glycol di-C1-6 alkyl ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, _dipropylene glycol dimethyl ether, triethylene glycol dimethyl ether, and tetraethylene _glycol dimethyl ether.

Examples of glycol ether acetates include cellosolve acetates such as methyl cellosolve acetate, carbitol acetates such as methyl carbitol acetate, and (poly)C _2-4 alkylene glycol mono-C _1-4 alkyl ether acetates such as propylene glycol monomethyl ether acetate (PGMEA) and dipropylene glycol monobutyl ether acetate.

Examples of ketones include chain ketones such as acetone, methyl ethyl ketone (MEK), and methyl isobutyl ketone (MIBK); and cyclic ketones such as cyclohexanone. Examples of carboxylic acids include acetic acid and propionic acid.

Esters include chain esters and cyclic esters. Chain esters include acetate esters such as methyl acetate, ethyl acetate, and butyl acetate, and lactate esters such as methyl lactate. Cyclic esters (or lactones) include 5- to 7-membered ring lactones that may have a substituent, such as gamma-butyrolactone, gamma-valerolactone, and gamma-caprolactone (or gamma-hexanolactone).

Examples of carbonates include chain carbonates and cyclic carbonates. Examples of chain carbonates include di-C 1-6 alkyl carbonates such as dimethyl carbonate (or dimethyl carbonate), ethyl methyl carbonate, and diethyl carbonate (or diethyl carbonate). Examples of cyclic carbonates include 5- to ₇ -membered ring carbonates such as ethylene carbonate (or ethylene carbonate) and propylene carbonate (or propylene carbonate).

Examples of amides include linear amides and cyclic amides (or lactams). Examples of linear amides include N,N-diC _1-6 alkyl-C _1-6 alkanoic acid amides such as N,N-dimethylformamide (DMF), N,N-diethylformamide, and N,N-dimethylacetamide (DMAc). Examples of cyclic amides include 5- to 7-membered ring lactams such as N-methyl-2-pyrrolidone.

Examples of ureas (or ureas) include chain ureas and cyclic ureas. Examples of chain ureas include tetra-C _1-6 alkyl-ureas such as tetramethylurea, tetraethylurea, and tetraisopropylurea. Examples of cyclic ureas include N,N'-di-C 1-6 alkyl-N,N'-di- or tetramethyleneureas such as _1,3 -dimethyl-2-imidazolidinone (DMI or N,N'-dimethylethyleneurea) and N,N'-dimethyl-N,N'-trimethyleneurea (or N,N'-propyleneurea).

Examples of nitriles include cyanated C _1-6 alkanes such as acetonitrile and propionitrile, and cyanated arenes such as benzonitrile.

Examples of nitrated hydrocarbons include nitro C _1-6 alkanes such as nitromethane, nitroethane, 1-nitropropane and 2-nitropropane, and nitroarenes such as nitrobenzene.

Examples of phosphoramides include hexaC _1-6 alkylphosphoramide such as hexamethylphosphoramide.

Examples of sulfones include chain sulfones and cyclic sulfones. Examples of chain sulfones include di-C _1-6 alkyl sulfones such as ethyl methyl sulfone and isopropyl ethyl sulfone. Examples of cyclic sulfones include tri- to hexamethylene sulfones such as sulfolane (or tetramethylene sulfone or tetrahydrothiophene-1,1-dioxide), 3-methyl sulfolane, and 2,4-dimethyl sulfolane.

Examples of sulfoxides include di-C _1-6 alkyl sulfoxides such as dimethyl sulfoxide (DMSO).

These solvents may be used alone or in combination of two or more. Among these solvents, aromatic hydrocarbons such as toluene, alcohols such as methanol, and ketones such as MEK and MIBK are typically used, with alcohols such as methanol being particularly common.

The organic solvent content, in terms of HPLC area percentage, is, for example, approximately 0.2% or less, with preferred ranges being 0.1% or less, 0.05% or less, 0.03% or less, more preferably 0.02% or less, and particularly 0.01% or less. The organic solvent content may be, for example, approximately 3500 ppm to 4800 ppm by mass, preferably 3700 ppm to 4600 ppm by mass, and more preferably 3900 ppm to 4400 ppm by mass. If the organic solvent content is too high, discoloration may not be suppressed when used as a resin raw material, or it may be difficult to adjust the resin composition to the desired ratio. Furthermore, if the compound represented by formula (1) is a powder, fluidity or handleability may be reduced. When the compound represented by formula (1) is a powder, containing a specified proportion of organic solvent may help suppress scattering and improve fluidity or handleability.

The content of aromatic hydrocarbons, particularly toluene, is, for example, about 0.2% or less in terms of HPLC area percentage, with preferred ranges being 0.1% or less, 0.05% or less, 0.03% or less, more preferably 0.02% or less, and particularly 0.01% or less. The content of aromatic hydrocarbons, particularly toluene, is, for example, 1% by mass or less, preferably 0.5% by mass or less, and more preferably 0.3% by mass or less. If the amount of aromatic hydrocarbons, such as toluene, is too high, when the compound represented by formula (1) is in powder form, the flowability or handleability may be reduced. Furthermore, when used as a resin raw material, coloration may not be suppressed or it may be difficult to adjust the desired resin composition ratio.

(j) Water The compound represented by formula (1) may or may not contain water (or moisture). The moisture content is, for example, 1% by mass or less, preferably 0.8% by mass or less, and more preferably 0.5% by mass or less. The moisture content may be, for example, approximately 6,000 ppm by mass to 12,000 ppm by mass, preferably 7,000 ppm by mass to 11,900 ppm by mass, and more preferably 8,000 ppm by mass to 11,800 ppm by mass. If the moisture content is too high, when used as a resin raw material, coloration may not be suppressed, the polymerization catalyst may be deactivated, or it may be difficult to adjust the desired resin composition ratio. Furthermore, when the compound represented by formula (1) is a powder, the fluidity or handleability may be reduced. When the compound represented by formula (1) contains moisture at a predetermined ratio, coloration in the resin may be suppressed, and when the compound represented by formula (1) is a powder, scattering may be easily suppressed, thereby improving the fluidity or handleability.

(Characteristics of fluorene compounds)
The fluorene compound of the present invention has a content of specific impurity components adjusted to a predetermined range, and therefore coloration (or discoloration), particularly coloration under high temperature conditions, can be effectively suppressed or reduced.

Therefore, the hue APHA of the fluorene compound, when maintained in a molten state at 280°C for 2 hours, is, for example, 500 or less, with preferred ranges being 450 or less, 400 or less, 350 or less, more preferably 300 or less, and particularly 270 or less, in the following stepwise order.

The hue YI of the fluorene compound, when maintained in a molten state at 280°C for 2 hours, is, for example, 100 or less, with preferred ranges being 85 or less, 80 or less, 75 or less, 70 or less, 65 or less, 60 or less, 55 or less, and 50 or less, more preferably 48 or less, and particularly 45 or less.

The heating residue of the fluorene compound at 180°C is, for example, 97% or more, preferably 98% or more, more preferably 99% or more, and particularly 99.5% or more. If the heating residue is too low, it may be difficult to prepare the desired resin composition when used as a resin raw material.

The bulk density of the fluorene compound is, for example, 0.4 to 0.8 mg/mL, preferably 0.5 to 0.75 mg/mL.

The melting point of the fluorene compound may be, for example, about 130 to 230°C. When Z ^1a and Z ^1b are ring-assembled arene rings such as biphenyl rings, it is 135 to 165°C, preferably 140 to 160°C, and more preferably 145 to 155°C. When Z ^1a and Z ^1b are fused polycyclic arene rings such as naphthalene rings, it may be, for example, about 200 to 230°C, with preferred ranges being 210 to 225°C, 215 to 223°C, 216 to 222°C, 216.5 to 221°C, 217 to 220.5°C, and 217.5 to 220°C, in the following stepwise order. If the impurity content is too high, the melting point may be lowered.

In this specification and claims, the color APHA, color YI, heating residue, bulk density, and melting point can be measured by the methods described in the examples below.

(Method for producing fluorene compound)
The method for producing the fluorene compound represented by formula (1) is not particularly limited, and the compound can be prepared by a conventional method. Typical methods include a method (first method) in which polycyclic aryloxy alcohols corresponding to the polycyclic arene rings Z ^1a and Z ^1b and the alkylene groups A ^1a and A ^1b in formula (1) are reacted with 9-fluorenones corresponding to the substituent R ¹ and its substitution number n1 in the presence of a catalyst such as an acid, a co-catalyst such as a thiol, a solvent, etc.; and a method (second method) in which 9,9-bis(hydroxypolycyclic aryl)fluorenes obtained by using polycyclic phenols corresponding to the polycyclic arene rings of Z ^1a and Z ^1b instead of the polycyclic aryloxy alcohols in the above method are further added to alkylene oxides (alkylene carbonates or haloalkanols) corresponding to the alkylene groups A ^1a and A ^1b in the presence of a catalyst such as 1-methylimidazole, etc. The first method is preferable in that by-products such as alkylene oxide non-adducts, mono-adducts, tri-adducts, etc. (such as the above-mentioned other impurity component (a)) are unlikely to be contained. The second method is preferable in that the compound represented by formula (11) can be easily contained in a predetermined ratio.

In the first method, examples of the polycyclic aryloxy alcohols include compounds corresponding to the fluorene compound represented by formula (1) above, including preferred embodiments thereof, more preferably _C10-14 polycyclic aryloxy _C2-4 alcohols such as 2-(2-naphthoxy)ethanol and 2-(o-phenylphenoxy)ethanol, still more preferably _C10-14 fused polycyclic aryloxy _C2-4 alcohols, and particularly preferably naphthoxy C2-3 alcohols such as _2- (2-naphthoxy)ethanol.

The 9-fluorenones include compounds corresponding to the fluorene compound represented by formula (1) above, including preferred embodiments thereof, and among these, 9-fluorenone is preferred.

The ratio of the polycyclic aryloxy alcohols to the 9-fluorenones used in the reaction is, for example, former/latter (molar ratio) = 1/2 to 1/10, with preferred ranges being 1/2.5 to 1/5, 1/3 to 1/4.5, and 1/3.5 to 1/4, in the following stepwise order. If the ratio of either the polycyclic aryloxy alcohols or the 9-fluorenones is too high, the impurity content may be high.

Examples of acid catalysts used in the reaction include inorganic acids, organic acids, and solid acids.

Examples of inorganic acids include sulfuric acid, hydrogen chloride, and phosphoric acid. The inorganic acid may be in the form of an aqueous solution, such as hydrochloric acid, and the concentration of the hydrochloric acid is, for example, 5 to 36% by mass, preferably 20 to 36% by mass.

Examples of organic acids include sulfonic acids. Examples of sulfonic acids include (halo)alkanesulfonic acids such as methanesulfonic acid and trifluoromethanesulfonic acid, and arenesulfonic acids such as p-toluenesulfonic acid.

Examples of solid acids include inorganic solid acids and organic solid acids. Examples of inorganic solid acids include metal compounds such as metal oxides, composite metal oxides, metal sulfides, metal sulfates, and polyacids, as well as non-metal sulfates, clay minerals, zeolites, and kaolin. Examples of organic solid acids include cation exchange resins such as strong acid cation exchange resins and weak acid cation exchange resins. Examples of strong acid cation exchange resins include ion exchange resins with sulfonic acid groups, such as DuPont's Nafion. Examples of weak acid cation exchange resins include ion exchange resins with carboxylic acid groups, such as (meth)acrylic acid-divinylbenzene copolymer.

These acid catalysts can be used alone or in combination of two or more. Preferred acid catalysts are inorganic acids such as sulfuric acid and cation exchange resins. Sulfuric acid, particularly concentrated sulfuric acid, is preferred because it also acts as a dehydrating agent for the water produced as the reaction progresses.

Examples of the sulfuric acid include dilute sulfuric acid with a concentration of about 30 to 90% by mass, concentrated sulfuric acid with a concentration of 90% by _mass or more, fuming sulfuric acid, etc., and sulfur trioxide may be used as a sulfuric acid precursor as long as it can be converted to sulfuric acid in the reaction system. Typically, the sulfuric acid may be selected from a range of about 80 to 99% by mass in terms of _H2SO4 , with preferred ranges being 90 to 99% by mass, 93 to 99% by mass, and 96 to 99% by mass, more preferably 97 to 98.5% by mass, and particularly preferably 98% by mass.

The proportion of acid catalyst can be selected, for example, from a range of approximately 10 to 1,000 parts by mass per 100 parts by mass of the 9-fluorenones. Preferred ranges are 50 to 800 parts by mass, 100 to 600 parts by mass, 150 to 500 parts by mass, and 200 to 450 parts by mass, in the following stepwise order, and more preferably 250 to 400 parts by mass, and particularly 270 to 360 parts by mass. If the proportion of acid catalyst is too low, the reaction may not proceed efficiently (or the reaction rate may be significantly reduced).

As thiols used as promoters, first thiols such as 2-mercaptoalkanoic acid, aminoalkanethiol, and salts thereof are preferred, as they can effectively reduce residual sulfur (the content of the third impurity component) and also reduce discoloration due to heat melting.

Examples of 2-mercaptoalkanoic acids include 2-mercapto C 2-6 alkanoic acids such as thioglycolic acid (mercaptoacetic acid or mercaptoethanoic acid), thiolactic acid (or α-mercaptopropionic acid), 2-mercaptobutyric acid (or 2-mercapto-n-butanoic acid), and 2-mercaptoisobutyric acid (or 2-mercapto-isobutanoic acid). Preferred 2-mercaptoalkanoic acids are ₂ -mercapto C _2-4 alkanoic acids, and particularly preferred are 2-mercapto C _2-3 alkanoic acids such as thioglycolic acid and thiolactic acid.

Examples of aminoalkanethiols include amino C 2-20 alkanethiols such as 2-aminoethanethiol (or cysteamine), 2-aminopropanethiol, 3-aminopropanethiol, 2-aminobutanethiol, 3-aminobutanethiol, 4-aminobutanethiol, 6-aminohexanethiol, 8-aminooctanethiol, 11-aminoundecanethiol, and 16 _{-aminohexadecanethiol. A preferred aminoalkanethiol is amino C 2-16 alkanethiol} .

Typical salts include, for example, inorganic acid salts such as hydrochloride and sulfate; organic acid salts such as acetate; alkali metal salts such as sodium salt and potassium salt; alkaline earth metal salts such as calcium salt and magnesium salt; ammonium salt and tetraalkylammonium salt such as tetramethylammonium salt; or double salts of these.

These first thiols can be used alone or in combination of two or more. Among these first thiols, from the viewpoint of significantly reducing residual sulfur (total sulfur content) and improving yield, it is preferable to include at least an aminoalkanethiol or a salt thereof, more preferably an amino C _2-12 alkanethiol, an amino C _2-8 alkanethiol, an amino C _2-6 alkanethiol, or an amino C _2-4 alkanethiol in the following stepwise order, still more preferably an amino C _2-3 alkanethiol, and particularly preferably cysteamine.

If necessary, the thiols may contain other thiols (also simply referred to as second thiols) that are different from the first thiols. Examples of second thiols include thiocarboxylic acids, mercaptocarboxylic acids (excluding 2-mercaptoalkanoic acids), alkyl mercaptans, aralkyl mercaptans, and salts thereof.

Examples of thiocarboxylic acids include thioacetic acid and thiooxalic acid.

Examples of mercaptocarboxylic acids (excluding 2-mercaptoalkanoic acids) include β-mercaptopropionic acid, mercaptosuccinic acid, and mercaptobenzoic acid.

Examples of alkyl mercaptans include C _1-16 alkyl mercaptans such as methyl mercaptan, ethyl mercaptan, propyl mercaptan, isopropyl mercaptan, n-butyl mercaptan, dodecyl mercaptan, etc. Preferred alkyl mercaptans are C _1-4 alkyl mercaptans.

Examples of aralkyl mercaptans include benzyl mercaptan.

These salts include, for example, the aforementioned alkali metal salts, typically sodium salts, and specific compounds include, for example, sodium methyl mercaptan and sodium ethyl mercaptan.

These second thiols can be used alone or in combination of two or more. Since the inclusion of second thiols, particularly mercaptocarboxylic acids such as β-mercaptopropionic acid (excluding 2-mercaptoalkanoic acids), can increase the content of impurities, it is preferable to avoid their substantial inclusion.

The proportion of the first thiols can be selected from a range of, for example, 10% by mass or more (e.g., 10 to 100% by mass) relative to the total thiols. Preferred ranges are, in the following order, 30% by mass or more, 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, and even more preferably 90% by mass or more. Of these, 95% by mass or more is preferred, and 100% by mass (an embodiment in which the thiols essentially contain only the first thiols) is particularly preferred. If the proportion of the first thiols is too low, it may be impossible to effectively reduce the total sulfur content or discoloration after heat melting. Note that when the thiols contain second thiols, the proportion of the first thiols can be selected from a range of, for example, 60 to 99.9% by mass relative to the total thiols, preferably 80 to 99% by mass, and even more preferably 90 to 98% by mass.

The proportion of thiols may be, for example, 0.1 parts by mass or more, specifically, selected from the range of approximately 1 to 50 parts by mass, relative to 100 parts by mass of the 9-fluorenones. Preferred ranges are 2 to 30 parts by mass, 3 to 20 parts by mass, 4 to 15 parts by mass, 5 to 10 parts by mass, and more preferably 6 to 9 parts by mass, with 6.5 to 8 parts by mass being particularly preferred, and 7 to 7.5 parts by mass being particularly preferred.

The proportion of thiols relative to 100 parts by mass of the acid catalyst can be selected, for example, from 0.01 parts by mass or more, specifically from a range of approximately 0.1 to 50 parts by mass. Preferred ranges are 0.5 to 30 parts by mass, 1 to 20 parts by mass, 1.5 to 10 parts by mass, 2 to 5 parts by mass, 2.3 to 4 parts by mass, 2.4 to 3.5 parts by mass, and 2.5 to 3 parts by mass, in the following stepwise order.

If the proportion of thiols is too low, not only may the reaction not proceed efficiently, but there is also a risk of discoloration due to impurities such as unreacted components. If the proportion is too high, the thiols may remain as impurities such as sulfur components. However, by using the first thiols, impurities such as sulfur components can be effectively reduced, and discoloration of the fluorene compound represented by formula (1) when melted can also be effectively suppressed.

Reaction solvents include, for example, hydrocarbons and halogenated hydrocarbons (also referred to as the first solvent).

Examples of hydrocarbons include aliphatic hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons. Examples of aliphatic hydrocarbons include linear or branched _C5-12 alkanes such as hexane, heptane, octane, and decane. Examples of alicyclic hydrocarbons include _C5-10 cycloalkanes such as cyclohexane. Examples of aromatic hydrocarbons include benzene; mono- to tri- _C1-6 alkylbenzenes such as toluene, xylene, and ethylbenzene.

Examples of halogenated hydrocarbons include haloC _1-6 alkanes such as methylene chloride, chloroform, carbon tetrachloride and 1,2-dichloroethane; and halobenzenes such as chlorobenzene and dichlorobenzene.

These first solvents may be used alone or in combination of two or more. Among these first solvents, aromatic hydrocarbons are preferred, and mono- to tri-C _1-4 alkyl-benzenes are more preferred, with mono- or di-C _1-2 alkyl-benzenes such as toluene, xylene, and ethylbenzene being particularly preferred, and toluene being particularly preferred.

In addition to the first solvent, the reaction solvent may or may not further contain an aprotic polar solvent (also referred to as the second solvent). The inclusion of the second solvent may allow the reaction to proceed efficiently even at low reaction temperatures, effectively suppressing the production of by-products and reducing impurities such as sulfur components, and may also effectively suppress the coloration of the fluorene compound represented by formula (1) due to heat melting.

Examples of aprotic polar solvents include ethers, ketones, esters, carbonates, amides, ureas, nitriles, nitrated hydrocarbons, phosphoramides, sulfones, and sulfoxides.

Examples of ethers include chain ethers, cyclic ethers, and anisole.

Examples of chain ethers include di-C _1-6 alkyl ethers such as diethyl ether, diisopropyl ether, and dibutyl ether; and (mono- to hexa)C _{2-4 alkylene glycol di-C 1-6} alkyl ethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, triethylene glycol dimethyl ether, and tetraethylene glycol _dimethyl ether.

Examples of cyclic ethers include tetrahydrofurans, such as tetrahydrofuran (THF) and 2-methyltetrahydrofuran, which may have a substituent; tetrahydropyrans, such as tetrahydropyran and 4-methyltetrahydropyran, which may have a substituent; dioxanes, such as 1,4-dioxane, 1,3-dioxane, and 4-methyl-1,3-dioxane, which may have a substituent; and dioxolanes, such as 1,3-dioxolane and 2-methyl-1,3-dioxolane, which may have a substituent. Examples of the substituent include hydrocarbon groups such as alkyl groups. When substituted, preferred substituents are C _1-6 alkyl groups such as methyl and ethyl groups, more preferably C _1-4 alkyl groups, and particularly methyl groups. The number of substituents is not particularly limited and is typically about 0 to 3, preferably 0 to 2, more preferably 0 or 1, and particularly 0.

Examples of ketones include chain ketones and cyclic ketones. Examples of chain ketones include di-C _1-6 alkyl ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone. Examples of cyclic ketones include C _5-10 cycloalkanones such as cyclohexanone.

Examples of esters include linear esters and cyclic esters (or lactones). Examples of linear esters include C _2-6 alkanoic acid C _1-6 alkyl esters such as methyl acetate, ethyl acetate, and butyl acetate. Examples of lactones include 5- to 7-membered lactones which may have a substituent, such as γ-butyrolactone, γ-valerolactone, and γ-caprolactone (or γ-hexanolactone). The substituents and the number of substitutions are the same as those exemplified for the cyclic ethers, including preferred embodiments.

Examples of carbonates include linear carbonates and cyclic carbonates. Examples of linear carbonates include di-C _1-6 alkyl carbonates such as dimethyl carbonate (or dimethyl carbonate), ethyl methyl carbonate, and diethyl carbonate (or diethyl carbonate). Examples of cyclic carbonates include di- or tetramethylene carbonates which may have a substituent, such as ethylene carbonate (or ethylene carbonate) and propylene carbonate (or propylene carbonate). The substituents and the number of substitutions are the same as those exemplified for the cyclic ethers, including preferred embodiments.

Examples of amides include linear amides and cyclic amides (or lactams). Examples of linear amides include N,N-diC _1-6 alkyl-C _1-6 alkanoic acid amides such as N,N-dimethylformamide (DMF), N,N-diethylformamide, and N,N-dimethylacetamide (DMAc). Examples of cyclic amides include lactams which may have a substituent, such as N-methyl-2-pyrrolidone (NMP), preferably 5- to 7-membered lactams which may have a substituent. The substituents and the number of substitutions are the same as those exemplified for the cyclic ethers, including preferred embodiments.

Examples of ureas (or ureas) include chain ureas and cyclic ureas. Examples of chain ureas include tetra-C _1-6 alkyl-ureas such as tetramethylurea, tetraethylurea, and tetraisopropylurea. Examples of cyclic ureas include N,N'-di-C 1-6 alkyl-N,N'-di- or tetramethyleneurea such as _1,3 -dimethyl-2-imidazolidinone (DMI or N,N'-dimethylethyleneurea) and N,N'-dimethyl-N,N'-trimethyleneurea (or N,N'-propyleneurea). These cyclic ureas may have a substituent, and the substituent and the number of substitutions are the same as those exemplified for the cyclic ethers, including preferred embodiments.

Examples of nitriles include cyanated hydrocarbons, specifically cyanated C _1-6 alkanes such as acetonitrile and propiononitrile, and cyanated arenes such as benzonitrile.

Examples of nitrated hydrocarbons include nitro C _1-6 alkanes such as nitromethane, nitroethane, 1-nitropropane and 2-nitropropane, and nitroarenes such as nitrobenzene.

Examples of phosphoramides include hexaC _1-6 alkylphosphoramide such as hexamethylphosphoramide.

Examples of sulfones include linear sulfones and cyclic sulfones. Examples of linear sulfones include di-C _1-6 alkyl sulfones such as ethyl methyl sulfone and isopropyl ethyl sulfone. Examples of cyclic sulfones include tri- to hexamethylene sulfones which may have a substituent, such as sulfolane (or tetramethylene sulfone or tetrahydrothiophene-1,1-dioxide), 3-methyl sulfolane, and 2,4-dimethyl sulfolane. The substituents and the number of substitutions are the same as those exemplified for the cyclic ethers, including preferred embodiments. Preferred cyclic sulfones include tetra- to pentamethylene sulfones which may have a C _1-6 alkyl group, such as sulfolane.

Examples of sulfoxides include di-C _1-6 alkyl sulfoxides such as dimethyl sulfoxide (DMSO).

These aprotic polar solvents (second solvents) can be used alone or in combination of two or more. Preferred aprotic polar solvents include ethers, sulfones, sulfoxides, ureas, and amides, more preferably ethers, sulfones, ureas, and amides, and even more preferably contain cyclic compounds (aprotic polar solvents having a cyclic structure) that have at least one ring structure within the molecule, with cyclic ethers, cyclic sulfones, cyclic ureas, and cyclic amides being particularly preferred.

Examples of the cyclic ethers include tetrahydrofurans or dioxanes which may have a C _1-4 alkyl group, such as THF and 1,4-dioxane. Of these, dioxanes which may have a C _1-3 alkyl group are preferred, and 1,4-dioxanes which may have a C _1-2 alkyl group, such as 1,4-dioxane, are particularly preferred, with 1,4-dioxane being most preferred.

Examples of the cyclic sulfones include tetra- to pentamethylene sulfones, such as sulfolane, which may have a _C1-4 alkyl group; sulfolanes which may have a _C1-3 alkyl group are more preferred; sulfolanes which may have a C1-2 alkyl group are even more preferred; and _sulfolane is most preferred.

Examples of the cyclic ureas include N,N'-di-C1-6 alkyl-N,N'-di- or trimethylene ureas which may have a _{C1-4 alkyl} group, such as DMI and N,N'-dimethyl-N,N'-trimethylene urea, more preferably N,N'-di- _C1-4 alkyl-ethylene ureas which may have a _C1-3 alkyl group, even more preferably N,N'-di- _C1-3 alkyl-ethylene ureas which may have a _C1-2 alkyl group, and most preferably DMI.

Examples of the cyclic amides include 5- to 7-membered lactams which may have a _C1-4 alkyl group, such as NMP, more preferably 5- to 6-membered lactams which may have a _C1-3 alkyl group, even more preferably 5-membered lactams which may have a _C1-2 alkyl group, and most preferably NMP.

The total proportion of the first solvent and the aprotic polar solvent (second solvent) relative to the total solvent can be selected, for example, from a range of approximately 10% by mass or more (i.e., 10 to 100% by mass). Preferred ranges are 30% by mass or more, 50% by mass or more, 70% by mass or more, 90% by mass or more, and even more preferably 95% by mass or more. 100% by mass, i.e., a solvent consisting essentially of the first and/or second solvent, is particularly preferred. If a solvent other than the first and second solvents (also referred to as a third solvent) is included, the total proportion of the first solvent and the second solvent can be selected, for example, from a range of approximately 60 to 99% by mass, and is preferably 80 to 95% by mass.

When the solvent contains both a first solvent and an aprotic polar solvent (second solvent), the mass ratio of the first solvent to the second solvent can be selected from a range of, for example, approximately 50/50 to 99.9/0.1, with preferred ranges being 70/30 to 99/1, 80/20 to 98/2, 82/18 to 97/3, 85/15 to 96/4, 87/13 to 95/5, 88/12 to 93/7, and 89/11 to 91/9. If the proportion of the aprotic polar solvent is too high, reactivity (reaction rate or reaction rate) may decrease; if it is too low, viscosity may not be reduced, resulting in decreased reactivity.

The solvent ratio may be selected from a range of, for example, approximately 100 to 1,000 parts by mass per 100 parts by mass of 9-fluorenones, with preferred ranges being 150 to 800 parts by mass, 200 to 700 parts by mass, 250 to 680 parts by mass, 280 to 650 parts by mass, and 300 to 630 parts by mass, in the following stepwise order. If the solvent ratio is too high, the raw material concentration may be too low, resulting in reduced reactivity; if the solvent ratio is too low, the viscosity may be too high, resulting in reduced reactivity.

In addition, in this specification and claims, when an acid catalyst such as sulfuric acid or hydrochloric acid contains water, the water contained in the acid catalyst is treated as the acid catalyst rather than the solvent, and is not included in the proportion of the solvent.

The reaction temperature is not particularly limited, but can be selected from a range of approximately 0 to 200°C, with preferred ranges being 5 to 100°C, 10 to 80°C, 20 to 70°C, 30 to 60°C, 35 to 55°C, and 40 to 50°C, in the following stepwise order. The reaction time is also not particularly limited, and can be selected from a range of approximately 30 minutes to 48 hours, with preferred ranges being 1 to 24 hours, 3 to 12 hours, and 5 to 8 hours, in the following stepwise order.

The reaction may be carried out with stirring, in air, or in an inert atmosphere such as nitrogen gas or a rare gas, and may be carried out under normal pressure, elevated pressure, or reduced pressure. The reaction may also be carried out while dehydrating.

The reaction mixture (reaction liquid or reaction mixture) after completion of the reaction contains, in addition to the target product or reaction product, the fluorene compound represented by formula (1), unreacted polycyclic aryloxy alcohols, the 9-fluorenones, the compound represented by formula (4), an acid catalyst, thiols, a solvent, water, etc. The fluorene compound represented by formula (1) can be separated (or purified) from such a reaction mixture using conventional methods, such as filtration, concentration, extraction, neutralization, washing, drying, crystallization, recrystallization, column chromatography, or a combination of these methods.

For example, the fluorene compound represented by formula (1) may be separated and purified by adding an alkaline aqueous solution such as an aqueous sodium hydroxide solution, neutralizing the mixture, washing, or the like to remove the acid catalyst (and thiols), followed by crystallization.

Examples of solvents used during crystallization include aromatic hydrocarbons such as toluene, ethers such as 1,4-dioxane, ketones such as acetone and methyl ethyl ketone, alcohols such as methanol, ethanol, and isopropanol, and water. These solvents can be used alone or in combination of two or more. Among these solvents, those containing ketones are preferred, with chain ketones such as di-C _1-4 alkyl ketones being more preferred, and acetone being particularly preferred. Crystallization using a solvent containing ketones, particularly acetone, is preferred because it further reduces the content of impurities and easily improves the purity of the fluorene compound represented by formula (1). Furthermore, as a mixed solvent, a mixed solvent containing an aromatic hydrocarbon, an ether and/or a ketone, and water is preferred.

Crystallization may be carried out by adding seed crystals. The temperature when adding the seed crystals is, for example, 30 to 50°C, preferably 35 to 45°C.

Crystallization may be cooling crystallization, and the cooling rate is, for example, 1 to 20°C/hour, preferably 5 to 15°C/hour, and more preferably 8 to 12°C/hour. The temperature reached after cooling is, for example, -10 to 20°C, preferably 0 to 10°C. Cooling may be carried out after adding seed crystals and aging (or leaving to stand) for, for example, 1 to 10 hours, preferably 2 to 5 hours to precipitate crystals. After cooling to the aforementioned temperature, the mixture may be further aged (or left to stand) for, for example, 1 to 10 hours, preferably 2 to 5 hours to precipitate crystals. Cooling crystallization may be repeated multiple times by changing the crystallization conditions as appropriate.

The crystals obtained by crystallization may be further washed or rinsed with the solvent used for the crystallization. During washing, the crystals may be washed with a solvent cooled to a low temperature, or may be washed while heated. Among the solvents used for crystallization, aromatic hydrocarbons such as toluene, or alcohols such as methanol or isopropanol are often used for washing. Washing with an alcohol such as methanol while heating, for example, at 40°C or above, preferably 50 to 70°C, and more preferably 55 to 65°C, is particularly preferred, as it can help reduce residual sulfur.

Crystallization may be performed one or more times, but it is preferable to perform it at least two times in order to effectively reduce the content of impurities. When crystallization is performed multiple times, the type of solvent used for crystallization may be the same or different.

In addition, crystallization typically precipitates the target fluorene compound represented by formula (1), but the purity of the fluorene compound may also be improved by precipitating impurities that crystallize more easily than the fluorene compound. For example, the fluorene compound (and a mixture containing impurities) may be dissolved in a ketone such as acetone, and then impurity components such as the first impurity component represented by formula (2) may be precipitated and separated for purification by methods such as aging (or leaving to stand), cooling, or removing the solvent under reduced pressure.

In the present invention, the fluorene compound obtained by the above-mentioned method is purified to adjust the content of specific impurities to a predetermined ratio.

In the second method, examples of the 9,9-bis(hydroxypolycyclic aryl)fluorene include compounds corresponding to the fluorene compound represented by formula (1) above, including preferred embodiments thereof, and more preferably include 9,9-bis(hydroxy C10-14 polycyclic aryl)fluorenes such as 9,9-bis(6-hydroxy-2-naphthyl)fluorene (also referred to as BNF) and 9,9-bis(5-hydroxy-1 _- naphthyl)fluorene. The 9,9-bis(hydroxypolycyclic aryl)fluorene may be a commercially available product.

Examples of alkylene oxides include _C2-6 alkylene oxides such as ethylene oxide, propylene oxide, and butylene oxide (1,2-epoxybutane), preferably _C2-4 alkylene oxide. Examples of alkylene carbonates include _C2-6 alkylene carbonates such as ethylene carbonate, propylene carbonate, and butylene carbonate, preferably _C2-4 alkylene carbonate. Examples of haloalkanols include _haloC2-6 alkanols such as chloroethanol, preferably _haloC2-4 alkanols. By reacting alkylene oxides (alkylene carbonates or haloalkanols), it is possible to introduce (poly)oxyalkylene units via the hydroxyl groups of the 9,9-bis(hydroxypolycyclic aryl)fluorenes. When an alkylene carbonate is used, the alkylene carbonate is added, followed by a decarboxylation reaction, whereby an oxyalkylene unit (alkoxy unit) is introduced.

The ratio of the 9,9-bis(hydroxypolycyclic aryl)fluorene to the alkylene oxide (alkylene carbonate or haloalkanol) used in the reaction is, for example, 1/2 to 1/50 (molar ratio), with preferred ranges being 1/2 to 1/40, 1/2 to 1/30, and 1/2 to 1/20, in the following stepwise order. When the compound represented by formula (11) is incorporated at a specific ratio to improve the molecular weight of the resin, the ratio of the former to the latter (molar ratio) is 1/2 to 1/15, preferably 1/3 to 1/13, even more preferably 1/5 to 1/12, even more preferably 1/6 to 1/10, and most preferably 1/7 to 1/9.

The reaction may be carried out in the absence of a catalyst, but is typically carried out in the presence of a catalyst. Examples of catalysts include base catalysts and acid catalysts, and typically, base catalysts are used. The base catalyst may be an inorganic base or an organic base. Inorganic bases include alkali metal or alkaline earth metal hydroxides such as sodium hydroxide, alkali metal or alkaline earth metal carbonates such as sodium carbonate, and alkali metal or alkaline earth metal bicarbonates such as sodium bicarbonate. Organic bases include trialkylamines such as triethylamine, aromatic tertiary amines such as N,N-dimethylaniline, heterocyclic tertiary amines such as 1-methylimidazole, and alkali metal or alkaline earth metal acetates such as sodium acetate and calcium acetate. These catalysts may be used alone or in combination. Of these, organic bases such as heterocyclic tertiary amines are preferred.

The catalyst content is, for example, 0.1 to 10 parts by mass, preferably 0.5 to 8 parts by mass, even more preferably 1 to 5 parts by mass, even more preferably 1.5 to 4 parts by mass, and most preferably 2 to 3 parts by mass, per 100 parts by mass of the 9,9-bis(hydroxypolycyclicaryl)fluorenes.

The reaction may be carried out in a solvent. Examples of solvents include ethers, hydrocarbons, halogenated hydrocarbons, and alcohols.

Examples of ethers, hydrocarbons, and halogenated hydrocarbons include the ethers, hydrocarbons, and halogenated hydrocarbons exemplified as reaction solvents in the first method.

Examples of alcohols include C _1-4 alcohols such as methanol, ethanol, and isopropanol; and (poly)C _2-3 alkylene glycols such as ethylene glycol, propylene glycol, diethylene glycol, and dipropylene glycol.

These solvents can be used alone or in combination. These solvents can be selected depending on the raw materials used. When alkylene oxide is used, the solvent may be an alcohol such as diethylene glycol.

The proportion of solvent is, for example, 100 to 1,000 parts by mass, preferably 200 to 800 parts by mass, and more preferably 300 to 500 parts by mass per 100 parts by mass of 9,9-bis(hydroxypolycyclicaryl)fluorenes. If the proportion of solvent is too high, the concentration of the raw materials may be too low, resulting in reduced reactivity. If the proportion of solvent is too low, the viscosity may be too high, resulting in reduced reactivity.

The reaction temperature is not particularly limited, but can be selected from a range of approximately 0 to 200°C, with preferred ranges being 30 to 180°C, 50 to 150°C, 60 to 140°C, 70 to 130°C, 80 to 120°C, and 90 to 110°C, in the following stepwise order. The reaction time is also not particularly limited, and can be selected from a range of approximately 30 minutes to 48 hours, with preferred ranges being 1 to 24 hours, 2 to 12 hours, and 3 to 8 hours, in the following stepwise order.

The reaction may be carried out with stirring, in air, or in an inert atmosphere such as nitrogen gas or a rare gas, and may be carried out under normal pressure, elevated pressure, or reduced pressure. The reaction may also be carried out while dehydrating. If necessary, the reaction may also be carried out while removing evolved gases (such as carbon dioxide).

After completion of the reaction, the reaction mixture (reaction liquid or reaction mixture) contains, in addition to the target product or reaction product, the fluorene compound represented by formula (1), unreacted 9,9-bis(hydroxypolycyclic aryl)fluorenes, the compound represented by formula (4), the compound represented by formula (11), a catalyst, a solvent, water, and the like. Methods such as those exemplified in the first method can be used to separate (or purify) the fluorene compound represented by formula (1) from such a reaction mixture. Of these methods, cooling crystallization is preferred.

[Resin made from fluorene compound]
The present invention also encompasses resins that use fluorene compounds with adjusted content of specific impurity components as raw materials or polymerization components. Perhaps because the raw material fluorene compounds are resistant to coloration even after undergoing chemical reactions such as polymerization, the resins exhibit significantly reduced coloration, making them useful for optical components. Furthermore, the resins exhibit excellent heat resistance and can improve glass transition temperatures. The resins may be heat- or photo-curable resins such as glycidyl ether-type epoxy resins and polyfunctional (meth)acrylic resins such as di(meth)acrylate, but are typically thermoplastic resins.

Examples of thermoplastic resins include polyester-based resins, thermoplastic polyurethane-based resins, and polyether-based resins. Of these resins, polyester-based resins containing ester bonds in the main chain, such as polyester resins, polycarbonate resins, and polyester-polycarbonate copolymers, are preferred. Of these, polycarbonate resins and polyester-polycarbonate copolymers are preferred, as they can further improve heat resistance while suppressing coloration, with polycarbonate resins being even more preferred.

In this specification and claims, the term "ester bond" is used to include not only [-C(=O)-O-] but also carbonate ester bonds [-O-C(=O)-O-].

(Polyester resin)
The polyester resin can be prepared by polymerizing a diol component containing at least a fluorene compound (first diol component) represented by the formula (1) with a dicarboxylic acid component. The fluorene compound represented by the formula (1) can be used alone or in combination of two or more.

If necessary, the diol component may contain a second diol component corresponding to the second diol unit represented by formula (12) below. The second diol component not only increases polymerization reactivity and facilitates an increase in molecular weight, but also may impart flexibility or toughness to the resin, significantly improving moldability and handleability.

(wherein ^A9 represents a linear or branched alkylene group, and m9 represents an integer of 1 or more).

In the formula (12), examples of the alkylene group represented by ^A9 include linear or branched _C2-12 alkylene groups such as ethylene, propylene, trimethylene, 1,2-butanediyl, 1,3-butanediyl, tetramethylene, 1,5-pentanediyl, 1,6-hexanediyl, 1,8-octanediyl, and 1,10-decanediyl. Preferred alkylene groups ^A9 include, in the following stepwise order, linear or branched _C2-10 alkylene groups, linear or branched _C2-8 alkylene groups, linear or branched _C2-6 alkylene groups, and linear or branched _C2-4 alkylene groups, more preferably linear or branched _C2-3 alkylene groups such as ethylene and propylene, with ethylene being particularly preferred.

The repeat number m9 can be selected, for example, from the range of about 1 to 10, and preferred ranges are 1 to 8, 1 to 6, 1 to 4, 1 to 3, and 1 to 2 in the following stepwise order, with 1 being particularly preferred. The repeat number m9 may be an average value (arithmetic mean value or additive mean value), and preferred embodiments are the same as those in the range of integers described above. When m9 is 2 or more, the types of the two or more oxyalkylene groups (-A ⁹ O-) may be different from each other, but are usually often the same.

Examples of the second diol component include alkanediols (or alkylene glycols), polyalkanediols (or polyalkylene glycols), etc.

Examples of the alkylene glycol include compounds in which m9 is 1 and ^A9 corresponds to the alkylene group exemplified above in formula (11), specifically linear or branched C2-12 alkylene glycols such as ethylene glycol, propylene glycol, trimethylene glycol, 1,2-butanediol, 1,3-butanediol, tetramethylene glycol (or 1,4-butanediol), 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,8-octanediol, and _1,10 -decanediol, and preferred embodiments are the same as those corresponding to the alkylene group ^A9 .

Examples of polyalkylene glycols include compounds in which m8 in the formula (12) is 2 or more, for example, about 2 to 10, and ^A9 corresponds to the alkylene group exemplified above, specifically di- to deca-linear or branched C _2-12 alkylene glycols such as diethylene glycol, dipropylene glycol, and triethylene glycol, preferably di- to hexa-linear or branched C _2-6 alkylene glycols, and more preferably di- to tetra-linear or branched C _2-4 alkylene glycols.

These second diol units may be contained alone or in combination of two or more. A preferred second diol unit is an alkylene glycol, from the viewpoints that it is easy to improve the refractive index and it is difficult to reduce heat resistance, more preferably a linear or branched C _2-6 alkylene glycol, still more preferably a linear or branched C _2-4 alkylene glycol such as ethylene glycol, propylene glycol, or 1,4-butanediol, among which a structural unit derived from a linear or branched C _2-3 alkylene glycol such as ethylene glycol or propylene glycol, and particularly ethylene glycol.

The diol component may or may not contain a diol component (third diol component) different from the first and second diol components, as necessary.

Examples of the third diol component include alicyclic diols, aromatic diols (excluding the first diol component), and alkylene oxide (alkylene carbonate or haloalkanol) adducts of these diol components.

Examples of alicyclic diols include cycloalkanediols such as cyclohexanediol; bis(hydroxyalkyl)cycloalkanes such as cyclohexanedimethanol; and hydrogenated aromatic diols such as hydrogenated bisphenol A, which are exemplified below.

Examples of aromatic diols include dihydroxyarenes such as hydroquinone and resorcinol; aromatic aliphatic diols such as benzenedimethanol; bisphenols such as bisphenol A, bisphenol F, bisphenol AD, bisphenol C, bisphenol G, and bisphenol S; biphenols such as p,p'-biphenol; and compounds having a 9,9-bisphenylfluorene skeleton, such as compounds in which Z ^1a and Z ^1b in the formula (1) are replaced by benzene rings instead of polycyclic arene rings.

Examples of alkylene oxide (corresponding alkylene carbonate or haloalkanol) adducts of these diol components include _C2-4 alkylene oxide adducts, preferably _C2-3 alkylene oxide adducts such as ethylene oxide adducts and propylene oxide adducts, and the number of moles added is not particularly limited. Specific examples include adducts in which about 2 to 10 moles of ethylene oxide are added to 1 mole of a diol such as bisphenol A.

The diol component may contain these third diol components alone or in combination of two or more.

In the polyester resin, the total proportion of the first diol units and second diol units corresponding to the first diol component is, for example, 10 mol% or more, with preferred ranges being 30 mol% or more, 50 mol% or more, 70 mol% or more, 90 mol% or more, 95 mol% or more, and more preferably substantially 100 mol% based on the total diol units.

The ratio of the first diol units to the second diol units (molar ratio) may be approximately 99/1 to 50/50, with preferred ranges being 90/10 to 55/45, 80/20 to 60/40, and 75/25 to 65/35, in the following stepwise order. If the first diol units are too few, the coloration suppression effect may not be fully exerted, heat resistance and refractive index may be reduced, and birefringence may not be reduced. Conversely, if the amount is too large, polymerization reactivity may be reduced and flexibility may be reduced.

The dicarboxylic acid component is not particularly limited, but may or may not contain a first dicarboxylic acid component derived from a first dicarboxylic acid unit represented by the following formula (13a) or (13b). The inclusion of a first dicarboxylic acid unit tends to reduce birefringence while maintaining relatively high heat resistance and refractive index, and tends to improve polymerization reactivity even when the polymer has a rigid fluorene skeleton.

(In the formula, R ¹⁹ and R ²⁰ each independently represent a substituent, n19 and n20 each independently represent an integer of 0 to 8,
A ^10a , A ^10b and A ¹¹ each independently represent a divalent hydrocarbon group which may have a substituent;
and q represents an integer of 0 to 4.

In the formula (13a) or (13b), the substituents represented by R ¹⁹ and R ²⁰ and the number of substitutions n19 and n20 are the same as those of R ¹ and n1 in the formula (1), including preferred embodiments. In addition, preferred embodiments such as the type and substitution position of two or more R ¹⁹ and R ²⁰ are also the same as those of R ¹ and n1 in the formula (1).

The hydrocarbon group represented by A ^10a , A ^10b and A ¹¹ includes a linear or branched alkylene group, for example, a linear or branched C _{1-8 alkylene group such as a methylene group, an ethylene group, a trimethylene group, a propylene group, a 1,2-butanediyl group, a 2-methylpropane-1,3-diyl group, etc. Preferred alkylene groups include a linear or branched C 1-6 alkylene} group such as a methylene group, an ethylene group, a trimethylene group, a propylene group, a 2-methylpropane-1,3-diyl group, etc., and more preferred are linear or branched C _1-4 alkylene groups.

Examples of the substituent that the hydrocarbon group may have include substituents that are inactive in polymerization reactions (non-polymerizable groups), such as aryl groups such as phenyl groups, and cycloalkyl groups such as cyclohexyl groups. Examples of the substituted hydrocarbon groups A ^10a , A ^10b , and A ¹¹ include a 1-phenylethylene group and a 1-phenylpropane-1,2-diyl group.

The groups A ^10a and A ^10b are preferably linear or branched C _2-4 alkylene groups, particularly linear or branched C _2-3 alkylene groups such as ethylene and propylene, and particularly ethylene. The group A ¹¹ is preferably a linear or branched C _1-3 alkylene group such as methylene and ethylene.

In the formula (13b), the number of repeating methylene groups, q, is, for example, an integer of approximately 0 to 3, preferably an integer of 0 to 2, and more preferably 0 or 1.

Examples of the first dicarboxylic acid component corresponding to the structural unit represented by formula (13a) include compounds in which A ^10a and A ^10b are linear or branched C _2-6 alkylene groups, 9,9-bis(carboxy C _2-6 alkyl)fluorenes such as 9,9-bis(2-carboxyethyl)fluorene and 9,9-bis(2-carboxypropyl)fluorene, and ester-forming derivatives thereof.

Examples of the first dicarboxylic acid component corresponding to the structural unit represented by formula (13b) include 9-(dicarboxyC _2-8 alkyl)fluorene and ester-forming derivatives thereof, specifically compounds in which q is 0 and A ¹¹ is a linear or branched C _1-6 alkylene group, such as 9-(1,2-dicarboxyethyl)fluorene; and compounds in which q is 1 and A ¹¹ is a linear or branched C _1-6 alkylene group, such as 9-(2,3-dicarboxypropyl)fluorene.

These first dicarboxylic acid units may be contained alone or in combination of two or more. Among these first dicarboxylic acid units, it is preferable to contain at least a dicarboxylic acid unit represented by the formula (13a) above, from the viewpoint of facilitating reduction of birefringence, and a structural unit derived from a 9,9-bis(carboxyalkyl)fluorene such as 9,9-bis(carboxyC2-6 _alkyl )fluorene is more preferable. Among these, it is preferable to contain a structural unit derived from 9,9-bis( _carboxyC2-4 alkyl)fluorene, more preferably 9,9-bis(carboxyC2-3 alkyl)fluorene such as 9,9-bis( ₂ -carboxyethyl)fluorene or 9,9-bis(2-carboxypropyl)fluorene, and in particular 9,9-bis(2-carboxyethyl)fluorene.

The dicarboxylic acid component may or may not contain a dicarboxylic acid component (second dicarboxylic acid component) different from the first dicarboxylic acid component, as necessary.

Examples of the second dicarboxylic acid component include aromatic dicarboxylic acid components (excluding the first dicarboxylic acid component), alicyclic dicarboxylic acid components, and aliphatic dicarboxylic acid components.

Examples of the aromatic dicarboxylic acid component include monocyclic aromatic dicarboxylic acids, polycyclic aromatic dicarboxylic acids, and ester-forming derivatives thereof. Examples of the monocyclic aromatic dicarboxylic acids include benzene dicarboxylic acids such as phthalic acid, terephthalic acid, and isophthalic acid; alkyl benzene dicarboxylic acids, specifically C _1-4 alkyl benzene dicarboxylic acids such as 4-methylisophthalic acid; and the like.

Examples of polycyclic aromatic dicarboxylic acids include fused polycyclic aromatic dicarboxylic acids, specifically fused polycyclic C _{10-24 arene-dicarboxylic acids such as naphthalenedicarboxylic acid, anthracenedicarboxylic acid, and phenanthrenedicarboxylic acid, preferably fused polycyclic C 10-14} arene-dicarboxylic acids; aryl arene dicarboxylic acids, specifically C _6-10 aryl-C _{6-10 arene-dicarboxylic acids such as 2,2'-biphenyldicarboxylic acid and 4,4'-biphenyldicarboxylic acid; diarylalkane dicarboxylic acids, specifically diC 6-10 aryl} C _1-6 alkane-dicarboxylic acids such as 4,4'-diphenylmethanedicarboxylic acid; and diaryl ketone dicarboxylic acids, specifically _{di(C 6-10 aryl} )ketone-dicarboxylic acids such as 4,4'-diphenylketone dicarboxylic acid.

Examples of the naphthalenedicarboxylic acid include 1,2-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, and 2,6-naphthalenedicarboxylic acid, with 2,3-naphthalenedicarboxylic acid being the most common.

Examples of the alicyclic dicarboxylic acid component include cycloalkane dicarboxylic acids, specifically C _5-10 cycloalkane-dicarboxylic acids such as 1,4-cyclohexane dicarboxylic acid; bridged cyclic cycloalkane dicarboxylic acids, specifically di- or tricycloalkane dicarboxylic acids such as decalin dicarboxylic acid, norbornane dicarboxylic acid, adamantane dicarboxylic acid, tricyclodecane dicarboxylic acid; cycloalkene dicarboxylic acids, specifically C _5-10 cycloalkene-dicarboxylic acids such as cyclohexene dicarboxylic acid; bridged cyclic cycloalkene dicarboxylic acids, specifically di- or tricycloalkene dicarboxylic acids such as norbornene dicarboxylic acid; and ester-forming derivatives thereof.

Examples of the aliphatic dicarboxylic acid component include alkanedicarboxylic acids, specifically C _2-12 alkane-dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and decanedicarboxylic acid; unsaturated aliphatic dicarboxylic acids, specifically C _2-10 alkene-dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid; and ester-forming derivatives thereof.

These second dicarboxylic acid components may be used alone or in combination of two or more.

The proportion of the first dicarboxylic acid units relative to the total dicarboxylic acid units is, for example, 10 mol% or more, with preferred ranges being 30 mol% or more, 50 mol% or more, 70 mol% or more, 90 mol% or more, 95 mol% or more, and more preferably substantially 100 mol%. If the proportion of the first dicarboxylic acid units is too low, the heat resistance and refractive index may decrease, or birefringence may increase.

The polyester resin does not necessarily contain any other structural units different from the diol units and dicarboxylic acid units, but may contain them if necessary.

Other structural units include, for example, structural units derived from hydroxyalkanoic acids and corresponding lactones, polyfunctional polymerization components having three or more carboxyl groups and/or hydroxyl groups, and carbonate bond-forming components.

Examples of the hydroxyalkanoic acids and corresponding lactones include hydroxyalkanoic acids such as lactic acid, 3-hydroxybutyric acid, and 6-hydroxyhexanoic acid; and lactones corresponding to hydroxyalkanoic acids such as ε-caprolactone.

Examples of the polyfunctional polymerizable component include polyfunctional polymerizable components having a total of three or more carboxyl groups and/or hydroxyl groups, such as trivalent or higher polycarboxylic acids such as trimellitic acid and pyromellitic acid, and trivalent or higher polyhydric alcohols such as glycerin and pentaerythritol.

The carbonate ester-forming component may be any compound capable of forming a carbonate ester bond upon reaction with two diol components. In other words, a "structural unit derived from a carbonate ester bond-forming component" refers to a carbonyl group [-C(=O)-], which forms a carbonate ester bond together with the terminal oxygen atoms of the two diol units bonded adjacent to this carbonyl group. Typical carbonate ester bond-forming components include, for example, phosgenes such as phosgene and triphosgene, and carbonate diesters such as diphenyl carbonate. The polyester-polycarbonate copolymer can be formed by including a structural unit derived from such a carbonate ester bond-forming component.

The proportion of such other structural units relative to the total amount of structural units (total amount of diol units, dicarboxylic acid units, and other structural units) is, for example, 50 mol% or less, with preferred ranges being 40 mol% or less, 30 mol% or less, 20 mol% or less, 10 mol% or less, and 5 mol% or less, in the following stepwise order. In most cases, other structural units are generally not substantially contained. The proportion may be approximately 0 to 10 mol%, for example, 0.01 to 1 mol%.

The method for producing the polyester resin is not particularly limited except for using a diol component containing the first diol component as a polymerization component, and conventional methods can be used depending on the other polymerization components (copolymerization components). For example, the polyester resin can be produced by reacting a diol acid component corresponding to the aforementioned diol units with a dicarboxylic acid component corresponding to each of the aforementioned dicarboxylic acid units. Conventional methods include transesterification, melt polymerization methods such as direct polymerization, solution polymerization, and interfacial polymerization, with melt polymerization being preferred. The reaction may be carried out in the presence or absence of a solvent depending on the polymerization method.

The ratio (or charge ratio) of the dicarboxylic acid component to the diol component is typically the former/latter (molar ratio), for example, 1/1.2 to 1/0.8, preferably 1/1.1 to 1/0.9. However, this range is not necessarily required, and at least one component selected from each dicarboxylic acid component and each diol component may be used in excess of the intended introduction ratio. For example, a second diol component such as ethylene glycol that can be distilled from the reaction system may be used in excess of the ratio (or introduction ratio) introduced into the resin.

The reaction may be carried out in the presence of a catalyst. Conventional esterification catalysts, such as metal catalysts, can be used as the catalyst. Examples of metal catalysts include metal compounds containing alkali metals such as sodium; alkaline earth metals such as magnesium, calcium, and barium; transition metals such as titanium, manganese, and cobalt; Group 12 metals such as zinc and cadmium; Group 13 metals such as aluminum; Group 14 metals such as germanium and lead; and Group 15 metals such as antimony. Examples of metal compounds include alkoxides; organic acid salts such as acetates and propionates; inorganic acid salts such as borates and carbonates; and oxides, as well as hydrates of these. Representative metal compounds include germanium compounds such as germanium dioxide, germanium hydroxide, germanium oxalate, germanium tetraethoxide, and germanium-n-butoxide; antimony compounds such as antimony trioxide, antimony acetate, and antimony ethylene glycolate; titanium compounds such as tetra-n-propyl titanate, tetraisopropyl titanate, tetra-n-butyl titanate (titanium(IV) tetrabutoxide), titanium oxalate, and potassium titanium oxalate; manganese compounds such as manganese acetate tetrahydrate; and calcium compounds such as calcium acetate monohydrate.

These catalysts can be used alone or in combination of two or more. When using multiple catalysts, each catalyst can be added according to the progress of the reaction. Among these catalysts, manganese acetate tetrahydrate, calcium acetate monohydrate, germanium dioxide, titanium (IV) tetrabutoxide, etc. are preferred. The amount of catalyst used is, for example, 0.01×10 ⁻⁴ to 100×10 ⁻⁴ mol, preferably 0.1×10 ⁻⁴ to 40×10 ⁻⁴ mol, per 1 mol of the dicarboxylic acid component.

Furthermore, the reaction may be carried out in the presence of a stabilizer such as a heat stabilizer or an antioxidant, as necessary. Typically, a heat stabilizer is often used, and examples thereof include phosphorus compounds such as trimethyl phosphate, triethyl phosphate, triphenyl phosphate, dibutyl phosphate (dibutyl phosphate or dibutyl phosphate), phosphorous acid, trimethyl phosphite, and triethyl phosphite. Of these, dibutyl phosphate is often used. The amount of the heat stabilizer used is, for example, 0.01×10 ⁻⁴ to 100×10 ⁻⁴ mol, preferably 0.1×10 ⁻⁴ to 40×10 ⁻⁴ mol, per mol of the dicarboxylic acid component.

The reaction is usually carried out in an atmosphere of an inert gas, for example, nitrogen gas; or a rare gas such as helium or argon. The reaction can also be carried out under reduced pressure, for example, at about 1×10 ² to 1×10 ⁴ Pa. Usually, transesterification reactions are often carried out under an inert gas atmosphere such as nitrogen gas, and polycondensation reactions are often carried out under reduced pressure. The reaction temperature can be selected depending on the polymerization method; for example, the reaction temperature in melt polymerization is 150 to 320°C, preferably 180 to 310°C, and more preferably 200 to 300°C.

The polyester resin obtained in this way exhibits reduced coloration, high heat resistance, and high refractive index.

The color difference b* of polyester resins may be, for example, approximately 0 to 10, with the lower the better. Preferred ranges are as follows, in stages: 0.01 to 9, 0.1 to 8.5, 0.5 to 8, 1 to 7.5, 2 to 7, 3 to 6.5, and 4 to 6.

The glass transition temperature Tg of the polyester resin may be, for example, in the range of approximately 100 to 250°C, with preferred ranges being 120 to 200°C, 130 to 180°C, 140 to 160°C, and more preferably 145 to 150°C.

The refractive index of the polyester resin can be selected, for example, from a range of approximately 1.6 to 1.7 at a temperature of 20°C and a wavelength of 589 nm, preferably in the following stepwise ranges: 1.62 to 1.69, 1.64 to 1.68, 1.65 to 1.67, and more preferably 1.66 to 1.665.

The weight-average molecular weight Mw of the polyester resin can be measured by gel permeation chromatography (GPC) or the like, and can be selected from a range of, for example, approximately 10,000 to 1,000,000 in polystyrene equivalent, with preferred ranges being 15,000 to 150,000, 20,000 to 100,000, 25,000 to 80,000, 30,000 to 60,000, 35,000 to 50,000, and 40,000 to 45,000. If the weight-average molecular weight Mw is too low, heat resistance and moldability (productivity) may be reduced.

In this specification and claims, the color difference b*, glass transition temperature Tg, refractive index nD, and weight average molecular weight Mw can be measured by the methods described in the examples below.

(Polycarbonate resin)
The polycarbonate resin can be prepared by polymerizing a diol component containing at least the fluorene compound (first diol component) represented by formula (1) with a carbonate bond-forming component. The fluorene compound represented by formula (1) can be used alone or in combination of two or more.

The diol component may or may not contain a diol component different from the first diol component. Examples of other diol components include the second diol component and third diol component exemplified in the polyester resin section.

These other diol components can be used alone or in combination of two or more. Of these other diol components, aromatic diols and their alkylene oxide (alkylene carbonate or haloalkanol) adducts are preferred, and more preferred are bisphenols such as bisphenol A, bisphenol F, bisphenol AD, bisphenol C, bisphenol G, and bisphenol S; biphenols such as p,p'-biphenol; and compounds having a 9,9-bisphenylfluorene skeleton, such as compounds of formula (1) in which Z ^1a and Z ^1b are benzene rings instead of polycyclic arene rings, and alkylene oxide adducts thereof. Of these, bisphenols and their alkylene oxide adducts are preferred, and bis(hydroxyaryl)alkanes and their alkylene oxide adducts are particularly preferred, and most preferred are bis( _hydroxyC aryl)C _1-4 alkanes such as bisphenol A and bisphenol F and their C _2-4 alkylene oxide adducts.

In the polycarbonate resin, the ratio of the first diol units corresponding to the first diol component to the other diol units corresponding to the other diol components may be, for example, a former/latter (molar ratio) of approximately 90/10 to 10/90, with preferred ranges being 80/20 to 20/80, 70/30 to 30/70, 60/40 to 40/60, and more preferably 55/45 to 45/55, in the following stepwise order. If the ratio of the first diol units is too low, the coloration suppression effect may not be fully exerted, heat resistance and refractive index may be reduced, and birefringence may not be reduced.

The carbonate bond-forming components are the same as the phosgenes and carbonate diesters exemplified as components that form other structural units in the polyester resin section above.

Polycarbonate resins can be produced by reacting (polymerizing or condensing) a diol component with phosgenes or carbonate diesters using conventional methods, such as the phosgene method (solvent method) or the transesterification method (melt method). The diol component needs to contain at least the first diol component required to form the structural unit represented by formula (1), and may further contain the other diol components as needed. Of these methods, the transesterification method is preferred because it does not require a solvent.

In the transesterification method, the ratio of carbonate diesters per mole of diol component is, for example, 0.8 to 1.5 moles, preferably 0.9 to 1.2 moles.

The transesterification reaction may be carried out in the presence of a catalyst. Examples of the catalyst include various catalysts used in transesterification reactions, such as nitrogen-containing compounds and metal compounds.

Examples of nitrogen-containing compounds include quaternary ammonium hydroxides and tertiary amines.

Examples of quaternary ammonium hydroxides include tetraalkylammonium hydroxides such as tetramethylammonium hydroxide, tetraethylammonium hydroxide, and tetrabutylammonium hydroxide; and trialkyl-aralkylammonium hydroxides such as trimethylbenzylammonium hydroxide.

Tertiary amines include trialkylamines such as trimethylamine and triethylamine; dialkyl-aralkylamines such as dimethylbenzylamine; and triarylamines such as triphenylamine.

Examples of metals contained in metal compounds include alkali metals such as sodium; alkaline earth metals such as magnesium, calcium, and barium; transition metals such as manganese, zinc, cadmium, lead, cobalt, and titanium; metals from Group 13 of the periodic table such as aluminum; metals from Group 14 of the periodic table such as germanium; and metals from Group 15 of the periodic table such as antimony. Examples of metal compounds include alkoxides of the above metals; organic acid salts such as acetates and propionates; inorganic acid salts such as borates and carbonates; oxides; and hydroxides.

These catalysts can be used alone or in combination of two or more. Among these catalysts, nitrogen-containing compounds such as quaternary ammonium hydroxides are preferred, and tetraalkylammonium hydroxides such as tetramethylammonium hydroxide are particularly preferred. The amount of catalyst used is, for example, 0.01×10 ⁻⁴ to 100×10 ⁻⁴ mol, preferably 0.1×10 ⁻⁴ to 40×10 ⁻⁴ mol, per mol of the diol component.

If necessary, the reaction may be carried out in the presence of additives such as stabilizers. Examples of stabilizers include antioxidants and heat stabilizers.

The reaction can usually be carried out in an atmosphere of an inert gas, for example, nitrogen gas or a rare gas such as helium or argon. The reaction can also be carried out under reduced pressure, for example, at a reduced pressure of about 1×10 ² to 1×10 ⁴ Pa. The reaction temperature can be selected depending on the polymerization method; for example, the reaction temperature in the transesterification method is, for example, 150 to 320°C, preferably 200 to 310°C, and more preferably 250 to 300°C. In particular, when diphenyl carbonate is used as the carbonate diester, it is effective to carry out polycondensation at high temperature under reduced pressure while distilling off phenol.

The polycarbonate resin obtained in this manner exhibits reduced coloration, high heat resistance, and high refractive index.

The color difference b* of the polycarbonate resin may be, for example, approximately 0 to 17, with the lower the better. Preferred ranges are as follows, in stages: 0.01 to 30, 0.1 to 25, 0.3 to 20, 0.5 to 18, 0.7 to 16, 1 to 15, 5 to 14.5, 10 to 14, 11 to 13.5, and 11.5 to 13.

The glass transition temperature Tg of the polycarbonate resin may be, for example, in the range of approximately 100 to 250°C, with preferred ranges being 130 to 230°C, 150 to 200°C, 160 to 190°C, and 170 to 185°C, with 175 to 180°C being even more preferred.

The refractive index of the polycarbonate resin can be selected, for example, from a range of approximately 1.6 to 1.7 at a temperature of 20°C and a wavelength of 589 nm, preferably in the following stepwise ranges: 1.63 to 1.68, 1.64 to 1.67, 1.645 to 1.66, and more preferably 1.65 to 1.655.

The weight-average molecular weight Mw of the polycarbonate resin can be measured by gel permeation chromatography (GPC) or the like, and can be selected from a range of, for example, approximately 10,000 to 1,000,000 in polystyrene equivalent, with preferred ranges being 15,000 to 150,000, 20,000 to 100,000, 25,000 to 80,000, 30,000 to 50,000, 32,000 to 40,000, and 34,000 to 39,000. If the weight-average molecular weight Mw is too low, heat resistance and moldability (productivity) may be reduced.

In this specification and claims, the color difference b*, glass transition temperature Tg, refractive index nD, and weight average molecular weight Mw can be measured by the methods described in the examples below.

(Molded body)
Molded articles may be prepared using the resin of the present invention. The molded articles contain at least the resin and have excellent optical properties, such as a high refractive index, a low absolute value of birefringence, and a low Abbe number, as well as high heat resistance, and thus can be used as optical components such as optical films (or optical sheets) and optical lenses. Such molded articles may contain conventional additives. Examples of additives include fillers or reinforcing agents, colorants such as dyes and pigments, conductive agents, flame retardants, plasticizers, lubricants, mold release agents, antistatic agents, dispersants, flow control agents, leveling agents, antifoaming agents, surface modifiers, hydrolysis inhibitors, carbon materials, stabilizers, and stress-reducing agents. Examples of stabilizers include antioxidants, ultraviolet absorbers, and heat stabilizers. Examples of stress-reducing agents include silicone oil, silicone rubber, various plastic powders, and various engineering plastic powders. These additives may be used alone or in combination.

Molded articles can be produced using, for example, injection molding, injection compression molding, extrusion molding, transfer molding, blow molding, pressure molding, casting molding, etc.

The shape of the molded product is not particularly limited, and examples include one-dimensional structures such as linear, fibrous (or fiber-like) and thread-like structures, two-dimensional structures such as film-like, sheet-like and plate-like structures, and three-dimensional structures such as concave or convex lens-like, rod-like and hollow (tubular) structures.

In particular, the resin of the present invention is useful for forming optical films because it has various excellent optical properties. Therefore, the present invention also includes films (optical films or optical sheets) formed from the resin.

The average thickness of such films can be selected from a range of approximately 1 to 1000 μm depending on the application, for example, 1 to 200 μm, preferably 5 to 150 μm, and more preferably 10 to 120 μm.

Such films (optical films) can be produced by forming (or molding) the resin using conventional film-forming methods, such as casting (solvent casting), melt extrusion, or calendaring.

The film may be a stretched film. Even if the film of the present invention is a stretched film, it can maintain low birefringence. Such a stretched film may be either a uniaxially stretched film or a biaxially stretched film.

The stretching ratio in each direction for uniaxial or biaxial stretching is, for example, 1.1 to 10 times, preferably 1.2 to 6 times, and more preferably 1.5 to 3 times. In the case of biaxial stretching, equal stretching, for example, stretching of about 1.5 to 5 times in both the longitudinal and transverse directions, is acceptable, or uneven stretching, for example, stretching of about 1.1 to 4 times in the longitudinal direction and about 2 to 6 times in the transverse direction, is also acceptable. In the case of uniaxial stretching, longitudinal stretching, for example, stretching of about 2.5 to 8 times in the longitudinal direction, and transverse stretching, for example, stretching of about 1.2 to 5 times in the transverse direction, is also acceptable.

The average thickness of the stretched film is, for example, 1 to 150 μm, preferably 3 to 120 μm, and more preferably 5 to 100 μm.

Such stretched films can be obtained by stretching the film (or unstretched film) after film formation. There are no particular restrictions on the stretching method; in the case of uniaxial stretching, either wet stretching or dry stretching may be used, and in the case of biaxial stretching, either the tenter method (flat method) or the tube method may be used, although the tenter method is preferred as it provides excellent uniformity in stretched thickness.

The molded article may also be joined or adhered to another substrate. The type and material of the substrate are not particularly limited and may be, for example, a one-dimensional, two-dimensional, or three-dimensional substrate made of a resin material, ceramic material, metal material, or the like. For example, if the molded article is in the form of a film, it may be combined with a two-dimensional substrate such as a film to form a laminate or laminate film.

Typical examples of the two-dimensional substrate include ceramic substrates such as glass substrates, and resin films, which are usually transparent. Examples of resins that form the resin film include polyolefin resins such as linear olefin resins and cyclic olefin resins (or cycloolefin resins); (meth)acrylic resins; styrene resins; polyester resins such as polyalkylene arylate resins, polyarylate resins, and polycarbonate resins; and polyamide resins. In particular, the substrate may be used in combination with a resin film formed from a cycloolefin resin, polyamide resin, or the like.

The present invention will be explained in more detail below based on examples, but the present invention is not limited to these examples. Details of the evaluation items and raw materials are provided below.

[Evaluation method]
(HPLC)
Using a Shimadzu Corporation "Nexera-i LC-2040C Plus" HPLC (high performance or high performance liquid chromatograph) apparatus and a Shimadzu GLC Corporation "Luna PFP (2)" column, the sample was dissolved in acetonitrile to a 2000-fold dilution, and acetonitrile and a 0.1% by mass aqueous phosphoric acid solution were used as eluents to measure the HPLC purity of the main component and the proportion [area %] of a predetermined minor component. The detection limit of the measuring device was 0.01% by area.

(GC)
The sample was dried under reduced pressure at 80°C overnight, then dissolved in tetrahydrofuran or dioxane, and the amount of remaining solvent [area %] was measured using a gas chromatography GC device (Shimadzu Corporation "GC-2014", column: CBP-1, detector: FID) at a measurement temperature range of 40 to 290°C. The detection limit of the measurement device was 0.01 area %.

(residual sulfur)
Residual sulfur (total sulfur content) was measured in terms of sulfur atoms by oxidative decomposition-ultraviolet fluorescence method using a "TS-2100H" manufactured by Mitsubishi Chemical Analytech Corporation.

(Hue APHA)
20 g of the sample was placed in a test tube, heated to 280°C in a nitrogen atmosphere, and maintained for 2 hours (molten sample). The hue of the sample was measured using a color difference turbidity meter ("COH-400" manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS K0071.

(Hue YI)
The hue (YI) [or yellowness index (YI)] was measured by melting the sample at 280° C. for 2 hours under a nitrogen stream and using a color and turbidity simultaneous measuring device ("COH-400" manufactured by Nippon Denshoku Industries Co., Ltd.).

(heated residue)
The heating residue (mass %) was measured at 180°C using a measuring device ("HX204 Halogen Moisture Meter" manufactured by Mettler Toledo K.K.).

(bulk density)
The bulk density [mg/mL] was measured according to the bulk density measurement method prescribed in the Japanese Pharmacopoeia.

(Melting point)
The measurement was carried out using a differential scanning calorimeter ("EXSTAR6000 DSC6220 ASD-2" manufactured by Hitachi High-Tech Science Corporation) under conditions of a nitrogen atmosphere, a measurement temperature of 40 to 300°C, and a temperature rise rate of 10°C/min.

(Refractive index nD)
The refractive index of the resin sample was measured as follows. The sample was heat-pressed at 200 to 240°C to form a film with a thickness of 200 to 300 μm. This film was cut into strips measuring 20 to 30 mm in length and 10 mm in width to obtain test pieces. The refractive index nD of the obtained test pieces at 589 nm (D line) was measured using a multi-wavelength Abbe refractometer (manufactured by Atago Co., Ltd., "DR-M4 (circulating constant temperature water bath 60-C3)") at a measurement temperature of 20°C and diiodomethane as a contact liquid.

(molecular weight)
The sample was dissolved in tetrahydrofuran (THF), and the weight average molecular weight Mw in terms of polystyrene was determined using gel permeation chromatography ("HLC-8320GPC" manufactured by Tosoh Corporation).

(Glass transition temperature Tg)
Measurement was carried out using a differential scanning calorimeter ("EXSTAR6000 DSC6220 ASD-2" manufactured by Hitachi High-Tech Science Corporation) in a nitrogen gas atmosphere at a temperature increase rate of 10°C/min.

(color difference b*)
Using a spectrophotometer (Konica Minolta, "SPECTROPHOTOMETER CM-3500"), the b* value of the Lab color difference system was measured at room temperature (20 to 30°C) under reflective conditions with a measuring diameter of 30 mm.

[Raw materials]
(Reagents used in the preparation of BNEF)
FLN: 9-fluorenone, manufactured by Osaka Gas Chemicals Co., Ltd., 99.0% or more NEO: 2-(2-naphthoxy)ethanol, manufactured by Osaka Gas Chemicals Co., Ltd., 99.0% or more PHE: 2-phenoxyethanol, manufactured by Kanto Chemical Co., Ltd., 99.0% or more Concentrated sulfuric acid: 98% by mass, manufactured by Kanto Chemical Co., Ltd. β-mercaptopropionic acid: manufactured by Tokyo Chemical Industry Co., Ltd., 98.0% or more Cysteamine: manufactured by Tokyo Chemical Industry Co., Ltd., 95.0% or more Sulfolane: manufactured by Tokyo Chemical Industry Co., Ltd., 99.0% or more BNF: 9,9-bis(6-hydroxy-2-naphthyl)fluorene, manufactured by Osaka Gas Chemicals Co., Ltd. Diethylene glycol: manufactured by Kanto Chemical Co., Ltd., 99.0% or more 1-methylimidazole: manufactured by Wako Pure Chemical Industries, Ltd., 98.0% or more

(Resin raw material)
EG: ethylene glycol; FDP-m: 9,9-bis(2-methoxycarbonylethyl)fluorene [or 9,9-bis(2-carboxyethyl)fluorene or dimethyl ester of fluorene-9,9-dipropionic acid]; synthesized in the same manner as in Example 1 of JP-A 2005-89422, except that methyl acrylate [37.9 g (0.44 mol)] was used instead of t-butyl acrylate; BisA: bisphenol A
DPC: diphenyl carbonate

Comparative Example 1 Preparation of BNEF (A) 90.1 g (0.500 mol) of FLN, 470.2 g (2.500 mol) of NEO, 562.3 g of toluene, and 9.0 g (0.085 mol) of β-mercaptopropionic acid were dissolved in a 2 L separable flask. After dissolution, 322.3 g of concentrated sulfuric acid was added dropwise at a temperature range of 40 to 45°C, and the mixture was stirred at 50°C for 4 hours. The conversion of FLN was confirmed to be 99% or higher by HPLC.

The resulting reaction liquid was pre-neutralized by adding 374.7 g of distilled water, 53.7 g of 48% by weight aqueous sodium hydroxide solution, and 280.9 g of dioxane. The temperature was then raised to 85-90°C and the mixture was thoroughly stirred. The aqueous phase was removed, and the resulting organic phase was washed multiple times with distilled water. Further, 249.8 g of distilled water, 7.4 g of concentrated sulfuric acid, and 107.3 g of 48% by weight aqueous sodium hydroxide solution were added. The mixture was stirred at 100°C for 2 hours for strong alkali treatment. After removing the aqueous phase, 135.2 g of dioxane was added to the resulting organic phase, which was thoroughly washed with distilled water. 374.7 g of toluene was added, and the mixture was cooled and crystallized.

For cooling crystallization, seed crystals were added to the resulting solution (organic phase) at 40°C, and the solution was aged for 3 hours to precipitate crystals. The solution was then cooled to below 10°C at a rate of 10°C/hour. After reaching below 10°C, the solution was aged for an additional 4 hours at a temperature range of 0-10°C, filtered, and rinsed with cold toluene adjusted to 0-10°C to obtain crude crystals. The resulting crude crystals were redissolved in 570.5 g of toluene, 285.5 g of dioxane, and 16.4 g of distilled water, and cooling crystallization was carried out. For cooling crystallization, seed crystals were added to the resulting solution (organic phase) at 55°C, and the solution was aged for 3 hours at 55°C to precipitate crystals. The solution was then cooled to below 10°C at a rate of 10°C/hour. After the temperature reached 10°C or below, the mixture was aged for a further 4 hours at a temperature range of 0 to 10°C, filtered, and rinsed with cold toluene adjusted to 0 to 10°C to obtain 168.7 g (63% yield, 98.03% HPLC purity) of the target product (9,9-bis[6-(2-hydroxyethoxy)-2-naphthyl]fluorene (BNEF)) (hereinafter referred to simply as BNEF (A)).

Example 1 Preparation of BNEF (B) 90.1 g (0.500 mol) of FLN, 376.5 g (2.000 mol) of NEO, 562.8 g of toluene, and 6.6 g (0.085 mol) of cysteamine were added to a 2 L separable flask and dissolved. After dissolution, 322.6 g of concentrated sulfuric acid was added dropwise at a temperature range of 40 to 45°C, and the mixture was stirred at 45°C for 7 hours. The conversion of FLN was confirmed to be 99% or higher by HPLC.

375.7 g of distilled water and 281.2 g of dioxane were added to the resulting reaction solution, which was then heated to 85°C and thoroughly stirred. The aqueous layer was then removed. Next, 107.5 g of 48% by weight aqueous sodium hydroxide, 187.4 g of dioxane, and 375.1 g of toluene were added, and the mixture was stirred at 95-100°C for 2 hours. After multiple water washes, 137.7 g of dioxane was added and cooling crystallization was carried out. For cooling crystallization, seed crystals were added to the resulting solution (organic phase) at 45°C, and the mixture was aged at 45°C for 3 hours to precipitate crystals. The mixture was then cooled to below 10°C at a rate of 10°C/hour. After reaching below 10°C, the mixture was aged for an additional 4 hours at a temperature range of 0-10°C and filtered. The mixture was then rinsed with cold toluene adjusted to 0-10°C and filtered, followed by rinsing with cold methanol adjusted to 0-10°C and filtering to obtain crude crystals. 649.0 g of methanol was added to the obtained crude crystals and stirred at 60 ° C. Then, it was cooled to room temperature (20 to 30 ° C.), filtered, rinsed with methanol, and filtered. Furthermore, the crude crystals were dissolved in 787.0 g of acetone and aged at 30 ° C., after which the precipitated FLN was removed by filtration, and the filtrate was concentrated, after which 513.3 g of toluene, 157.4 g of dioxane, and 13.8 g of distilled water were added, and cooling crystallization was carried out. For cooling crystallization, seed crystals were added to the obtained solution (organic phase) at 50 ° C., and the solution was aged for 3 hours at 50 ° C. to precipitate crystals, and then cooled to 10 ° C. or below at a rate of 10 ° C./hour. After reaching 10 ° C. or below, it was aged for another 4 hours in the temperature range of 0 to 10 ° C., filtered, rinsed with toluene, and filtered. Then, 792.0 g of methanol was added to the obtained crude crystals and stirred at 60 ° C. The mixture was then cooled to room temperature (20-30°C), filtered, and rinsed with methanol to obtain 132.1 g of the desired BNEF (49% yield, 99.10% HPLC purity) (hereinafter referred to simply as BNEF (B)).

Comparative Example 2: Preparation of BNEF (C) 90.1 g (0.500 mol) of FLN, 329.4 g (1.750 mol) of NEO, 281.4 g of toluene, and 6.6 g (0.085 mol) of cysteamine were added to a 2 L separable flask and dissolved. After dissolution, 244.9 g of concentrated sulfuric acid was added dropwise at a temperature range of 40 to 50 °C, followed by stirring at 50 °C for 6 hours. 69.0 g of PHE was then added and stirred at 50 °C for 3 hours. HPLC confirmed that the conversion of FLN was 99% or higher.

294.1 g of distilled water and 281.3 g of methyl ethyl ketone (MEK) were added to the resulting reaction solution, which was then heated to 75°C and thoroughly stirred. The aqueous layer was removed. 230.4 g of 25% by weight aqueous sodium hydroxide solution and 230.4 g of distilled water were then added, and the mixture was stirred at 75°C for 30 minutes. The aqueous layer was removed and the mixture was washed multiple times with distilled water. 11.9 g of distilled water was then added, and cooling crystallization was carried out. For cooling crystallization, seed crystals were added to the resulting solution (organic phase) at 45°C, and the mixture was aged at 45°C for 3 hours to precipitate crystals. The mixture was then cooled to below 10°C at a rate of 10°C/hour. After reaching below 10°C, the mixture was aged for an additional 4 hours at a temperature range of 0-10°C and filtered. The mixture was then rinsed with cold toluene adjusted to 0-10°C and filtered, followed by rinsing with cold methanol adjusted to 0-10°C and filtering to obtain crude crystals. 623.5 g of methanol was added to the obtained crude crystals, which were stirred at 60°C and then cooled to room temperature (20-30°C). The mixture was then filtered and rinsed with methanol to obtain 152.3 g of the desired BNEF (yield 57%, HPLC purity 97.33%) (hereinafter referred to simply as BNEF (C)).

Example 2: Preparation of BNEF (D) 90.1 g (0.500 mol) of FLN, 329.4 g (1.750 mol) of NEO, 278.3 g of toluene, and 6.6 g (0.085 mol) of cysteamine were added to a 2 L separable flask and dissolved. After dissolution, 245.0 g of concentrated sulfuric acid was added dropwise at a temperature range of 40 to 50°C, followed by stirring at 45 to 50°C for 6 hours. 69.2 g of PHE was then added and stirred at 45 to 50°C for 2 hours. HPLC confirmed that the conversion of FLN was 99% or higher.

294.0 g of distilled water and 281.3 g of MEK were added to the resulting reaction solution, which was then heated to 75°C and thoroughly stirred. The aqueous layer was removed. 80.7 g of 48% by weight aqueous sodium hydroxide solution and 311.4 g of distilled water were then added, and the mixture was stirred at 75°C for 30 minutes. The aqueous layer was removed and the mixture was washed multiple times with distilled water. 11.5 g of distilled water was then added, and cooling crystallization was carried out. For cooling crystallization, seed crystals were added to the resulting solution (organic phase) at 45°C, and the mixture was aged at 45°C for 3 hours to precipitate crystals. The mixture was then cooled to below 10°C at a rate of 10°C/hour. After reaching below 10°C, the mixture was aged for an additional 4 hours at a temperature range of 0-10°C and filtered. The mixture was then rinsed with cold toluene adjusted to 0-10°C and filtered, and then rinsed with cold methanol adjusted to 0-10°C and filtered to obtain crude crystals. To the obtained crude crystals, 737.5 g of methanol was added, and the mixture was stirred at 60 ° C., then cooled to room temperature (20-30 ° C.) and filtered to obtain crude crystals. Furthermore, 277.1 g of toluene, 83.1 g of acetone, 41.6 g of dioxane, and 10.0 g of distilled water were added to the obtained crude crystals, and the mixture was redissolved at 70 ° C., and 41.6 g of dioxane was added, followed by cooling crystallization. For cooling crystallization, seed crystals were added to the obtained solution (organic phase) at 35 ° C., and the mixture was aged at 35 ° C. for 3 hours to precipitate crystals, followed by cooling to 10 ° C. or below at a rate of 10 ° C./hour. After the temperature reached 10°C or below, the mixture was aged for a further 4 hours at a temperature between 0 and 10°C before filtering, then rinsed with cold toluene adjusted to 0 to 10°C and filtered, and then rinsed with cold methanol adjusted to 0 to 10°C and filtered again to obtain 137.2 g of the desired BNEF (yield 51%, HPLC purity 99.24%) (hereinafter referred to simply as BNEF (D)).

Example 3: Preparation of BNEF(E) 90.1 g (0.500 mol) of FLN, 329.4 g (1.750 mol) of NEO, 280.8 g of toluene, and 6.6 g (0.085 mol) of cysteamine were added to a 2 L separable flask and dissolved. After dissolution, 245.0 g of concentrated sulfuric acid was added dropwise at a temperature range of 40 to 50°C, followed by stirring at 40 to 50°C for 6 hours. 69.0 g of PHE was then added and stirred at 40 to 50°C for 3 hours. HPLC confirmed that the conversion of FLN was 99% or higher.

293.3 g of distilled water and 281.4 g of MEK were added to the resulting reaction solution, which was then heated to 75°C and thoroughly stirred. The aqueous layer was removed. 80.5 g of 48% by weight aqueous sodium hydroxide and 312.1 g of distilled water were then added, and the mixture was stirred at 75°C for 30 minutes. The aqueous layer was then removed, and the mixture was washed multiple times with distilled water, followed by cooling crystallization. For cooling crystallization, seed crystals were added to the resulting solution (organic phase) at 45°C, and the mixture was aged at 45°C for 3 hours to precipitate crystals. The mixture was then cooled to below 10°C at a rate of 10°C/hour. After reaching below 10°C, the mixture was aged for an additional 4 hours at a temperature range of 0-10°C, filtered, rinsed with cold toluene adjusted to 0-10°C, and then further rinsed with cold methanol adjusted to 0-10°C and filtered to obtain crude crystals. The resulting crude crystals were redissolved in 282.8 g of toluene and 283.0 g of MEK, 7.7 g of distilled water was added, and the mixture was concentrated. After 352.7 g of toluene was added, cooling crystallization was performed. For cooling crystallization, seed crystals were added to the resulting solution (organic phase) at 45°C, and the mixture was aged at 45°C for 3 hours to precipitate crystals. The mixture was then cooled to room temperature (20-30°C) at a rate of 10°C/hour and filtered. The mixture was then rinsed with cold toluene adjusted to 0-10°C and further rinsed with cold methanol adjusted to 0-10°C to obtain crude crystals. 500.4 g of methanol was then added to the crude crystals, stirred at 60°C, and cooled to room temperature (20-30°C). The mixture was then filtered and rinsed with methanol to obtain 141.2 g of the desired BNEF (53% yield, 98.33% HPLC purity) (hereinafter referred to simply as BNEF(E)).

Example 4: Preparation of BNEF (F) 90.1 g (0.500 mol) of FLN, 282.4 g (1.500 mol) of NEO, 210.4 g of toluene, 6.6 g (0.085 mol) of cysteamine, and 15.0 g (0.125 mol) of sulfolane were added to a 2 L separable flask and dissolved. After dissolution, 245.3 g of concentrated sulfuric acid was added dropwise at a temperature range of 25 to 40°C, followed by stirring at 40°C for 12 hours. 69.1 g of PHE was then added and stirred at 40°C for 3 hours. HPLC confirmed that the conversion of FLN was 99% or higher.

294.3 g of distilled water, 56.2 g of toluene, and 281.3 g of MEK were added to the resulting reaction solution, which was then heated to 75°C and thoroughly stirred. The aqueous layer was removed. 80.6 g of 48% by weight aqueous sodium hydroxide solution and 312.8 g of distilled water were then added, and the mixture was stirred at 75°C for 30 minutes. The aqueous layer was then removed, and the mixture was washed multiple times with distilled water, followed by cooling crystallization. For cooling crystallization, seed crystals were added to the resulting solution (organic phase) at 40°C, and the mixture was aged at 40°C for 3 hours to precipitate crystals. The mixture was then cooled to below 10°C at a rate of 10°C/hour. After reaching below 10°C, the mixture was aged for an additional 4 hours at a temperature range of 0-10°C and filtered. The mixture was then rinsed with cold toluene adjusted to 0-10°C and filtered, followed by rinsing with cold methanol adjusted to 0-10°C and filtering to obtain crude crystals. 657.6 g of methanol was added to the obtained crude crystals, which were stirred at 60°C and then cooled to room temperature (20-30°C). The mixture was then filtered and rinsed with methanol to obtain 162.2 g of the desired BNEF (yield 60%, HPLC purity 98.56%) (hereinafter referred to simply as BNEF(F)).

Example 5 Preparation of BNEF (G) 90.0 g (0.2 mol) of BNF, 88.1 g (2.0 mol) of ethylene oxide gas, and 300 g (3.4 mol) of diethylene glycol as a solvent were placed in a 2 L separable flask, and 2 g of 1-methylimidazole (manufactured by Wako Pure Chemical Industries, Ltd.) was added as a catalyst. The mixture was then heated to 100°C and reacted for 5 hours.

After the reaction was complete, 1,000 mL of isopropyl alcohol was added and cooling crystallization was carried out. Cooling crystallization involved cooling from 75°C to room temperature (20-30°C) at a rate of 10°C/hour. After crystallization, the mixture was aged at room temperature (20-30°C) for 3 hours to precipitate crystals, and then cooled to below 10°C at a rate of 10°C/hour. After reaching below 10°C, the mixture was aged for an additional 4 hours at a temperature range of 0-10°C. The mixture was then filtered and rinsed with cold isopropyl alcohol adjusted to 0-10°C to obtain 80.7 g of the desired BNEF (75% yield, 93.76% HPLC purity) (hereinafter simply referred to as BNEF (G)).

Example 6 Preparation of BNEF(H) 90.0 g (0.2 mol) of BNF, 70.5 g (1.6 mol) of ethylene oxide gas, and 300 g (3.4 mol) of diethylene glycol as a solvent were placed in a 2 L separable flask, and 2 g of 1-methylimidazole (manufactured by Wako Pure Chemical Industries, Ltd.) was added as a catalyst. The mixture was then heated to 100°C and reacted for 5 hours.

After the reaction was complete, 1,000 mL of isopropyl alcohol was added and cooling crystallization was carried out. Cooling crystallization involved cooling from 75°C to room temperature (20-30°C) at a rate of 10°C/hour. After crystallization, the mixture was aged at room temperature (20-30°C) for 3 hours to precipitate crystals, and then cooled to below 10°C at a rate of 10°C/hour. After reaching below 10°C, the mixture was aged for an additional 4 hours at a temperature range of 0-10°C. The mixture was then filtered and rinsed with cold isopropyl alcohol adjusted to 0-10°C to obtain 74.6 g of the desired BNEF (yield 69.3%, HPLC purity 94.44%) (hereinafter simply referred to as BNEF(H)).

[Example 7] Preparation of BNEF (I) 90.1 g (0.500 mol) of FLN, 282.4 g (1.500 mol) of NEO, 210.4 g of toluene, 6.6 g (0.085 mol) of cysteamine, and 21.0 g (0.18 mol) of sulfolane were added to a 2 L separable flask and dissolved. After dissolution, 245.0 g of concentrated sulfuric acid was added dropwise at a temperature range of 25 to 40 ° C, and the mixture was stirred at 40 ° C for 3 hours. Furthermore, 96.7 g of PHE was added and stirred at 40 ° C for 4 hours, and 24.5 g of concentrated sulfuric acid was added and stirred at 40 ° C for 5 hours. The conversion of FLN was confirmed to be 99% or more by HPLC.

452.8 g of distilled water, 70.0 g of toluene, and 281.3 g of MEK were added to the resulting reaction solution, which was then heated to 95°C and thoroughly stirred. The aqueous layer was removed. 89.8 g of 48% by weight aqueous sodium hydroxide solution and 204.8 g of distilled water were then added, and the mixture was stirred at 75°C for 30 minutes. The aqueous layer was then removed, and the mixture was washed multiple times with distilled water before undergoing cooling crystallization. For cooling crystallization, seed crystals were added to the resulting solution (organic phase) at 50°C, and the mixture was aged at 40°C for 4 hours to precipitate crystals. The mixture was then cooled to below 10°C at a rate of 10°C/hour. After reaching below 10°C, the mixture was aged for an additional 4 hours at a temperature range of 0-10°C and filtered. The mixture was then rinsed with cold toluene adjusted to 0-10°C and filtered, followed by rinsing with cold methanol adjusted to 0-10°C and filtering to obtain crude crystals. 712.9 g of methanol was added to the obtained crude crystals, which were stirred at 60°C and then cooled to room temperature (20-30°C). The mixture was then filtered and rinsed with methanol to obtain 167.0 g of the desired BNEF (yield 62%, HPLC purity 99.36%) (hereinafter referred to simply as BNEF (I)).

Example 8: Preparation of BNEF (J) 90.1 g (0.500 mol) of FLN, 282.4 g (1.500 mol) of NEO, 210.4 g of toluene, 6.6 g (0.085 mol) of cysteamine, and 21.0 g (0.18 mol) of sulfolane were added to a 2 L separable flask and dissolved. After dissolution, 245.0 g of concentrated sulfuric acid was added dropwise at a temperature range of 25 to 40 °C, followed by stirring at 40 °C for 3 hours. 96.7 g of PHE was then added and stirred at 40 °C for 4 hours. 24.5 g of concentrated sulfuric acid was added and stirred at 40 °C for 5 hours. The conversion of FLN was confirmed to be 99% or higher by HPLC.

452.8 g of distilled water, 70.0 g of toluene, and 281.3 g of MEK were added to the resulting reaction solution, which was then heated to 95°C and thoroughly stirred. The aqueous layer was removed. 89.8 g of 48% by weight aqueous sodium hydroxide solution and 204.8 g of distilled water were then added, and the mixture was stirred at 75°C for 30 minutes. The aqueous layer was then removed, and the mixture was washed multiple times with distilled water before undergoing cooling crystallization. For cooling crystallization, seed crystals were added to the resulting solution (organic phase) at 50°C, and the mixture was aged at 40°C for 4 hours to precipitate crystals. The mixture was then cooled to below 10°C at a rate of 10°C/hour. After reaching below 10°C, the mixture was aged for an additional 4 hours at a temperature range of 0-10°C and filtered. The mixture was then rinsed with cold toluene adjusted to 0-10°C and filtered, followed by rinsing with cold methanol adjusted to 0-10°C and filtering to obtain crude crystals. The resulting crude crystals were dissolved at 80°C with 404.0 g of methyl ethyl ketone (hereinafter referred to as MEK) and 712.9 g of toluene, followed by cooling and crystallization. For cooling and crystallization, seed crystals were added to the resulting solution (organic phase) at 50°C, and the solution was aged at 40°C for 4 hours to precipitate crystals. The solution was then cooled to below 10°C at a rate of 10°C/hour. After reaching below 10°C, the solution was aged for an additional 4 hours at a temperature range of 0-10°C and filtered. The solution was then rinsed with cold toluene adjusted to 0-10°C, filtered, and further rinsed with cold methanol adjusted to 0-10°C to obtain 123.6 g of the desired BNEF (yield 45.9%, HPLC purity 99.59%) (hereinafter referred to simply as BNEF(J)).

Comparative Example 3 Preparation of Polyester Resin A reactor was charged with BNEF(A) (64.1 g (0.119 mol)) and EG (22.1 g (0.357 mol)) as diol components, FDP-m (53.7 g (0.159 mol)) as a dicarboxylic acid component, and 858.8 mg of a 1.0 mass% ethylene glycol solution of manganese(II) acetate tetrahydrate (8.6 mg (0.04 mmol)), 4402.2 mg of a 0.9 mass% aqueous solution of germanium(IV) oxide (39.6 mg (0.28 mmol)), and 1243.7 mg of a 1.0 mass% aqueous solution of trimethyl phosphate (12.4 mg (0.09 mmol)) as catalysts for the transesterification reaction and polycondensation reaction. The mixture was gradually heated to 250°C under a nitrogen gas atmosphere and stirred to carry out a transesterification reaction. After removing the alcohol component produced by the transesterification reaction, the temperature was gradually increased to 275°C and the pressure was reduced to 330 Pa, and the polycondensation reaction was carried out while removing EG until a predetermined stirring torque was reached. After completion of the reaction, the content was removed from the reactor to obtain a polyester resin.

Example 9 Preparation of Polyester Resin A reactor was charged with BNEF(B) (69.9 g (0.130 mol)) and EG (24.2 g (0.389 mol)) as diol components, FDP-m (58.5 g (0.173 mol)) as a dicarboxylic acid component, and, as catalysts for the transesterification reaction and polycondensation reaction, 936.9 mg of a 1.0 mass% ethylene glycol solution of manganese(II) acetate tetrahydrate (9.4 mg (0.04 mmol)), 4802.4 mg of a 0.9 mass% aqueous solution of germanium(IV) oxide (43.2 mg (0.42 mmol)), and 1356.8 mg of a 1.0 mass% aqueous solution of trimethyl phosphate (12.2 mg (0.10 mmol)). The mixture was gradually heated to 250°C under a nitrogen gas atmosphere and stirred to carry out a transesterification reaction. After removing the alcohol component produced by the transesterification reaction, the temperature was gradually increased to 275°C and the pressure was reduced to 410 Pa, and the polycondensation reaction was carried out while removing EG until a predetermined stirring torque was reached. After completion of the reaction, the content was removed from the reactor to obtain a polyester resin.

Comparative Example 4 Preparation of Polyester Resin A reactor was charged with BNEF(C) (46.6 g (0.087 mol)) and EG (16.1 g (0.259 mol)) as diol components, FDP-m (39.0 g (0.115 mol)) as a dicarboxylic acid component, and, as catalysts for the transesterification reaction and polycondensation reaction, 624.6 mg of a 1.0 mass% ethylene glycol solution of manganese(II) acetate tetrahydrate (6.3 mg (0.03 mmol)), 3201.6 mg of a 0.9 mass% aqueous solution of germanium(IV) oxide (28.8 mg (0.28 mmol)), and 904.5 mg of a 1.0 mass% aqueous solution of trimethyl phosphate (9.1 mg (0.06 mmol)), and the mixture was gradually heated to 250°C under a nitrogen gas atmosphere and stirred to carry out a transesterification reaction. After removing the alcohol component produced by the transesterification reaction, the temperature was gradually increased to 275°C and the pressure was reduced to 570 Pa, and the polycondensation reaction was carried out while removing EG until a predetermined stirring torque was reached. After completion of the reaction, the content was removed from the reactor to obtain a polyester resin.

Example 10 Preparation of Polyester Resin A reactor was charged with BNEF(D) (69.9 g (0.130 mol)) and EG (24.2 g (0.389 mol)) as diol components, FDP-m (58.5 g (0.173 mol)) as a dicarboxylic acid component, and, as catalysts for the transesterification reaction and polycondensation reaction, 936.9 mg of a 1.0 mass% ethylene glycol solution of manganese(II) acetate tetrahydrate (9.4 mg (0.04 mmol)), 4802.4 mg of a 0.9 mass% aqueous solution of germanium(IV) oxide (43.2 mg (0.42 mmol)), and 1356.8 mg of a 1.0 mass% aqueous solution of trimethyl phosphate (12.2 mg (0.10 mmol)). The mixture was gradually heated to 250°C under a nitrogen gas atmosphere and stirred to carry out a transesterification reaction. After removing the alcohol component produced by the transesterification reaction, the temperature was gradually increased to 275°C and the pressure was reduced to 330 Pa, and the polycondensation reaction was carried out while removing EG until a predetermined stirring torque was reached. After completion of the reaction, the content was removed from the reactor to obtain a polyester resin.

Example 11 Preparation of Polyester Resin A reactor was charged with BNEF(E) (69.9 g (0.130 mol)) and EG (24.2 g (0.389 mol)) as diol components, FDP-m (58.5 g (0.173 mol)) as a dicarboxylic acid component, and, as catalysts for the transesterification reaction and polycondensation reaction, 936.9 mg of a 1.0 mass% ethylene glycol solution of manganese(II) acetate tetrahydrate (9.4 mg (0.04 mmol)), 4802.4 mg of a 0.9 mass% aqueous solution of germanium(IV) oxide (43.2 mg (0.42 mmol)), and 1356.8 mg of a 1.0 mass% aqueous solution of trimethyl phosphate (12.2 mg (0.10 mmol)). The mixture was gradually heated to 250°C under a nitrogen gas atmosphere and stirred to carry out a transesterification reaction. After removing the alcohol component produced by the transesterification reaction, the temperature was gradually increased to 275°C and the pressure was reduced to 530 Pa, and the polycondensation reaction was carried out while removing EG until a predetermined stirring torque was reached. After completion of the reaction, the content was removed from the reactor to obtain a polyester resin.

Example 12 Preparation of Polyester Resin A reactor was charged with BNEF(F) (69.9 g (0.130 mol)) and EG (24.2 g (0.389 mol)) as diol components, FDP-m (58.5 g (0.173 mol)) as a dicarboxylic acid component, and, as catalysts for the transesterification reaction and polycondensation reaction, 936.9 mg of a 1.0 mass% ethylene glycol solution of manganese(II) acetate tetrahydrate (9.4 mg (0.04 mmol)), 4802.4 mg of a 0.9 mass% aqueous solution of germanium(IV) oxide (43.2 mg (0.42 mmol)), and 1356.8 mg of a 1.0 mass% aqueous solution of trimethyl phosphate (12.2 mg (0.10 mmol)), and the mixture was gradually heated to 250°C under a nitrogen gas atmosphere and stirred to carry out a transesterification reaction. After removing the alcohol component produced by the transesterification reaction, the temperature was gradually increased to 275°C and the pressure was reduced to 440 Pa, and the polycondensation reaction was carried out while removing EG until a predetermined stirring torque was reached. After completion of the reaction, the content was removed from the reactor to obtain a polyester resin.

Example 13 Preparation of Polyester Resin A reactor was charged with BNEF(G) (69.9 g (0.130 mol)) and EG (24.2 g (0.389 mol)) as diol components, FDP-m (58.5 g (0.173 mol)) as a dicarboxylic acid component, and, as catalysts for the transesterification reaction and polycondensation reaction, 936.9 mg of a 1.0 mass% ethylene glycol solution of manganese(II) acetate tetrahydrate (9.4 mg (0.04 mmol)), 4802.4 mg of a 0.9 mass% aqueous solution of germanium(IV) oxide (43.2 mg (0.42 mmol)), and 1356.8 mg of a 1.0 mass% aqueous solution of trimethyl phosphate (12.2 mg (0.10 mmol)). The mixture was gradually heated to 250°C under a nitrogen gas atmosphere and stirred to carry out a transesterification reaction. After removing the alcohol component produced by the transesterification reaction, the temperature was gradually increased to 275°C and the pressure was reduced to 560 Pa, and the polycondensation reaction was carried out while removing EG until a predetermined stirring torque was reached. After completion of the reaction, the content was removed from the reactor to obtain a polyester resin.

Example 14 Preparation of Polyester Resin A reactor was charged with BNEF(H) (69.9 g (0.130 mol)) and EG (24.2 g (0.389 mol)) as diol components, FDP-m (58.5 g (0.173 mol)) as a dicarboxylic acid component, and, as catalysts for the transesterification reaction and polycondensation reaction, 936.9 mg of a 1.0 mass% ethylene glycol solution of manganese(II) acetate tetrahydrate (9.4 mg (0.04 mmol)), 4802.4 mg of a 0.9 mass% aqueous solution of germanium(IV) oxide (43.2 mg (0.42 mmol)), and 1356.8 mg of a 1.0 mass% aqueous solution of trimethyl phosphate (12.2 mg (0.10 mmol)). The mixture was gradually heated to 250°C under a nitrogen gas atmosphere and stirred to carry out a transesterification reaction. After removing the alcohol component produced by the transesterification reaction, the temperature was gradually increased to 275°C and the pressure was reduced to 370 Pa, and the polycondensation reaction was carried out while removing EG until a predetermined stirring torque was reached. After completion of the reaction, the content was removed from the reactor to obtain a polyester resin.

Example 15 Preparation of Polyester Resin A reactor was charged with BNEF(I) (69.9 g (0.130 mol)) and EG (24.2 g (0.389 mol)) as diol components, FDP-m (58.5 g (0.173 mol)) as a dicarboxylic acid component, and, as catalysts for the transesterification reaction and polycondensation reaction, 936.9 mg of a 1.0 mass% ethylene glycol solution of manganese(II) acetate tetrahydrate (9.4 mg (0.04 mmol)), 4802.4 mg of a 0.9 mass% aqueous solution of germanium(IV) oxide (43.2 mg (0.42 mmol)), and 1356.8 mg of a 1.0 mass% aqueous solution of trimethyl phosphate (12.2 mg (0.10 mmol)). The mixture was gradually heated to 250°C under a nitrogen gas atmosphere and stirred to carry out a transesterification reaction. After removing the alcohol component produced by the transesterification reaction, the temperature was gradually increased to 275°C and the pressure was reduced to 280 Pa, and the polycondensation reaction was carried out while removing EG until a predetermined stirring torque was reached. After completion of the reaction, the content was removed from the reactor to obtain a polyester resin.

Example 16 Preparation of Polyester Resin A reactor was charged with BNEF(J) (69.9 g (0.130 mol)) and EG (24.2 g (0.389 mol)) as diol components, FDP-m (58.5 g (0.173 mol)) as a dicarboxylic acid component, and, as catalysts for the transesterification reaction and polycondensation reaction, 936.9 mg of a 1.0 mass% ethylene glycol solution of manganese(II) acetate tetrahydrate (9.4 mg (0.04 mmol)), 4802.4 mg of a 0.9 mass% aqueous solution of germanium(IV) oxide (43.2 mg (0.42 mmol)), and 1356.8 mg of a 1.0 mass% aqueous solution of trimethyl phosphate (12.2 mg (0.10 mmol)), and the mixture was gradually heated to 250°C under a nitrogen gas atmosphere and stirred to carry out a transesterification reaction. After removing the alcohol component produced by the transesterification reaction, the temperature was gradually increased to 275°C and the pressure was reduced to 310 Pa, and the polycondensation reaction was carried out while removing EG until a predetermined stirring torque was reached. After completion of the reaction, the content was removed from the reactor to obtain a polyester resin.

Comparative Example 5 Preparation of Polycarbonate Resin BNEF(A) (60.4 g (112.1 mmol)) and BisA (25.6 g (112.1 mmol)) as diol components, DPC (50.4 g (235.4 mmol)), and 65.8 mg of a 0.5 wt % aqueous solution of sodium bicarbonate (0.33 mg (3.9 μmol)) as a transesterification catalyst were added, gradually heated to melt with stirring, and the temperature was raised to 250°C. After that, the temperature was gradually raised to 275°C and the pressure was reduced to 520 Pa, and phenol was removed while the pressure was reduced. After the predetermined stirring torque was reached, the contents were removed from the reactor, and a polycarbonate resin was obtained.

Example 17 Preparation of Polycarbonate Resin Diol components BNEF(B) (67.1 g (124.5 mmol)) and BisA (28.4 g (124.5 mmol)), DPC (56.0 g (261.5 mmol)), and 51.2 mg of a 0.5% by mass aqueous solution of sodium bicarbonate (0.37 mg (4.3 μmol)) as a transesterification catalyst were added, gradually heated to melt with stirring, and the temperature was raised to 250°C. After that, the temperature was gradually raised to 275°C and the pressure was reduced to 490 Pa, and phenol was removed while the pressure was reduced. After the predetermined stirring torque was reached, the contents were removed from the reactor, and a polycarbonate resin was obtained.

Comparative Example 6 Preparation of Polycarbonate Resin BNEF(C) (53.7 g (99.6 mmol)) and BisA (22.8 g (99.6 mmol)) as diol components, DPC (44.8 g (209.2 mmol)), and 58.5 mg of sodium bicarbonate (0.29 mg (3.5 μmol)) as a transesterification catalyst in the form of a 0.5% by mass aqueous solution were added, gradually heated to melt with stirring, and the temperature was raised to 250°C. After that, the temperature was gradually raised to 275°C and the pressure was reduced to 480 Pa, and phenol was removed while the pressure was reduced. After the predetermined stirring torque was reached, the contents were removed from the reactor, and a polycarbonate resin was obtained.

Example 18 Preparation of Polycarbonate Resin Diol components BNEF(D) (67.1 g (124.5 mmol)) and BisA (28.4 g (124.5 mmol)), DPC (56.0 g (261.5 mmol)), and 51.2 mg of a 0.5 wt % aqueous solution of sodium bicarbonate (0.37 mg (4.3 μmol)) as a transesterification catalyst were added, gradually heated to melt with stirring, and the temperature was raised to 250°C. After that, the temperature was gradually raised to 275°C and the pressure was reduced to 390 Pa, and phenol was removed while the pressure was reduced. After the predetermined stirring torque was reached, the contents were removed from the reactor, and a polycarbonate resin was obtained.

Example 19 Preparation of Polycarbonate Resin Diol components BNEF(E) (67.1 g (124.5 mmol)) and BisA (28.4 g (124.5 mmol)), DPC (56.0 g (261.5 mmol)), and 51.2 mg of a 0.5 wt% aqueous solution of sodium bicarbonate (0.37 mg (4.3 μmol)) as a transesterification catalyst were added, gradually heated to melt with stirring, and the temperature was raised to 250°C. After that, the temperature was gradually raised to 275°C and the pressure was reduced to 680 Pa, and phenol was removed while the pressure was reduced. After the predetermined stirring torque was reached, the contents were removed from the reactor, and a polycarbonate resin was obtained.

Example 20 Preparation of Polycarbonate Resin BNEF(F) (67.1 g (124.5 mmol)) and BisA (28.4 g (124.5 mmol)) as diol components, DPC (56.0 g (261.5 mmol)), and 51.2 mg of a 0.5 wt % aqueous solution of sodium bicarbonate (0.37 mg (4.3 μmol)) as a transesterification catalyst were added, gradually heated to melt with stirring, and the temperature was raised to 250°C. After that, the temperature was gradually raised to 275°C and the pressure was reduced to 810 Pa, and phenol was removed while the pressure was reduced. After the predetermined stirring torque was reached, the contents were removed from the reactor, and a polycarbonate resin was obtained.

Example 21 Preparation of Polycarbonate Resin BNEF(H) (67.1 g (124.5 mmol)) and BisA (28.4 g (124.5 mmol)) as diol components, DPC (56.0 g (261.5 mmol)), and 51.2 mg of a 0.5 wt % aqueous solution of sodium bicarbonate (0.37 mg (4.3 μmol)) as a transesterification catalyst were added, gradually heated to melt with stirring, and the temperature was raised to 250°C. After that, the temperature was gradually raised to 275°C and the pressure was reduced to 490 Pa, and phenol was removed while the pressure was reduced. After the predetermined stirring torque was reached, the contents were removed from the reactor, and a polycarbonate resin was obtained.

Example 22 Preparation of Polycarbonate Resin BNEF (I) (67.1 g (124.5 mmol)) and BisA (28.4 g (124.5 mmol)) as diol components, DPC (56.0 g (261.5 mmol)), and 51.2 mg of sodium bicarbonate (0.37 mg (4.3 μmol)) as a transesterification catalyst in the form of a 0.5% by mass aqueous solution were added, gradually heated to melt with stirring, and the temperature was raised to 250°C. After that, the temperature was gradually raised to 275°C and the pressure was reduced to 490 Pa, and phenol was removed while the pressure was reduced. After the predetermined stirring torque was reached, the contents were removed from the reactor, and a polycarbonate resin was obtained.

Example 23 Preparation of Polycarbonate Resin BNEF(J) (67.1 g (124.5 mmol)) and BisA (28.4 g (124.5 mmol)) as diol components, DPC (56.0 g (261.5 mmol)), and 51.2 mg of a 0.5% by mass aqueous solution of sodium bicarbonate (0.37 mg (4.3 μmol)) as a transesterification catalyst were added, gradually heated to melt with stirring, and the temperature was raised to 250°C. After that, the temperature was gradually raised to 275°C and the pressure was reduced to 490 Pa, and phenol was removed while the pressure was reduced. After the predetermined stirring torque was reached, the contents were removed from the reactor, and a polycarbonate resin was obtained.

The evaluation results of the Examples and Comparative Examples are shown in Tables 1 to 4. In Table 1, "1EO form" refers to an impurity component (a) in which ^Z3a and ^Z3b are naphthalene rings, n5 is 0, n6a and n6b are 0, ^A3b is an ethylene group, m3a is 0, and m3b is 1 in the formula (4), that is,

The "3EO form" refers to an impurity component (a) in which Z 3a and Z ^3b are naphthalene rings, n5 is 0, n6a and n6b are 0, A 3a and A 3b are ethylene groups, m3a is 1, and m3b is 2 in the formula (4), that is, the impurity component (a) in which Z ^3a and Z 3b are naphthalene rings, n5 is 0, n6a and n6b are 0, A ^3a and A ^3b are ethylene groups, m3a is 1, and m3b is 2, that is, the impurity component (a) in the formula (4)

and "trifunctional compound" refers to an impurity component (h) in which, in the formula (11), Z ^8a and Z ^8b are naphthalene rings, n17 is 0, n18a and n18b are 0, A ^8a to A ^8c are ethylene groups, m8a, m8b and m8c are 1, and m8d is 0, that is, a compound represented by the following formula:

"MIBK" means methyl isobutyl ketone; "MEK" means methyl ethyl ketone; "MeOH" means methanol; and "n.d." indicates that the value was below the detection limit of the measuring device.

As is clear from Tables 1 to 4, in the Examples, discoloration during melting or after polymerization was suppressed compared to the Comparative Examples, and the glass transition temperature (Tg) of the resin was also high. In particular, the Examples using BNEF(B), BNEF(D), BNEF(E), BNEF(I), and BNEF(J), which have relatively high purity and particularly low amounts of FLN, NEO, and residual sulfur, exhibited excellent discoloration suppression and heat resistance of the resin.

Those skilled in the art would recognize that an improvement in Tg of 3°C or more indicates a significant difference in resin performance. In particular, Example 19, which used BNEF (E), showed a significant improvement in Tg. The impurities that affect Tg are presumably FLN and residual sulfur. However, the improvement of 3°C or more was surprising compared to Example 17, which used BNEF (B), which had a FLN content of approximately 1/11 and a similar amount of residual sulfur, and Example 18, which used BNEF (D), which had a similar amount of FLN and residual sulfur. While the reasons for this are unclear, the comparison of Examples 18 and 19 (Examples 2 and 3) suggests that the low FLN content and residual sulfur are due to the presence of a certain proportion of 1EO units, and the comparison of Examples 11 and 19 suggests that the high proportion of BNEF-derived structural units in the overall resin is a contributing factor.

Furthermore, in Examples 13 and 14, which used BNEF (G) and (H) containing trifunctional units, the molecular weight of the polyester resin was improved, with a particularly notable effect being shown in Example 14, which used BNEF (H), which has a high proportion of trifunctional units. Furthermore, in Example 21, which used BNEF (H), the molecular weight of the polycarbonate resin was also improved.

The fluorene compounds of the present invention have excellent heat resistance and can suppress coloration, making them effective for use as resin raw materials, additives (or resin additives) such as heat resistance improvers and refractive index improvers.

Furthermore, resins made from the fluorene compounds of the present invention as raw materials (or polymer components) not only have high heat resistance and are capable of suppressing coloration, but also exhibit excellent optical properties such as a high refractive index, a low Abbe number, and low birefringence. Therefore, they may be used in a variety of applications, such as coating agents or coating films, specifically, paints, inks, and protective films for electronic devices and liquid crystal components; adhesives, pressure-sensitive adhesives; resin fillers; electrical and electronic materials or electrical and electronic components (electrical and electronic devices), specifically, antistatic agents, carrier transport agents, light-emitting bodies, organic photoreceptors, thermal recording materials, photochromic materials, hologram recording materials, charging trays, conductive sheets, optical disks, inkjet printers, digital paper, color filters, organic EL elements, organic semiconductor lasers, dye-sensitized solar cells, sensors, and EMI shielding films; and mechanical materials or mechanical components (equipment), specifically, automotive materials or components, aerospace-related materials or components, and sliding members.

The resin of the present invention has a good balance of excellent optical properties and high heat resistance, making it particularly effective for use as an optical component.

Typical optical components include optical films (optical sheets) such as films for liquid crystal displays and organic electroluminescence (EL) displays; optical lenses such as lenses for glasses and cameras; prisms, holograms, and optical fibers.

Examples of optical films include polarizing films, polarizing elements and polarizing plate protective films that constitute polarizing films, phase difference films, alignment films (orientation films), viewing angle widening (compensation) films, diffusion plates (films), prism sheets, light guide plates, brightness enhancement films, near-infrared absorbing films, reflective films, anti-reflection (AR) films, reflection reduction (LR) films, anti-glare (AG) films, transparent conductive (ITO) films, anisotropic conductive films (ACF), electromagnetic shielding (EMI) films, films for electrode substrates, films for color filter substrates, barrier films, color filter layers, black matrix layers, adhesive layers or release layers between optical films, etc. These optical films can be effectively used as optical films for displays such as liquid crystal displays (LCDs), organic light-emitting diode (OLED) displays, plasma displays (PDPs), field emission displays (FEDs), and electronic paper. Specific devices or apparatuses include televisions; personal computers (PCs) such as desktop PCs, notebook PCs, and tablet PCs; smartphones, mobile phones; car navigation systems; and devices or apparatuses equipped with flat panel displays (FPDs) such as touch panels.

Examples of optical lenses include eyeglass lenses, contact lenses, camera lenses, VTR zoom lenses, pickup lenses, Fresnel lenses, solar concentrating lenses, objective lenses, and rod lens arrays. In particular, the resins are suitable for use in lenses requiring a low Abbe number, such as camera lenses. Typical examples of devices or equipment incorporating such optical lenses include small or mobile devices with camera functions, such as smartphones, mobile phones, and digital cameras; and in-vehicle cameras, such as dashcams and backup cameras (rear cameras). In particular, the resins of the present invention have high heat resistance and are therefore suitable for use in applications where high-temperature environments are anticipated, such as in-vehicle optical lenses.

Claims (11)

The following formula (1)
(wherein Z ^1a and Z ^1b each independently represent a naphthalene ring;
^R1 represents a substituent; n1 represents an integer of 0 to 8;
R ^2a and R ^2b each independently represent a substituent; n2a and n2b each independently represent an integer of 0 or more;
A ^1a and A ^1b each independently represent a linear or branched alkylene group;
The following formula (2)
(In the formula, ^R3 represents a substituent, and n3 represents an integer of 0 to 8.)
The content of the compound represented by the formula (I) is 0.5% or less in terms of HPLC area ratio,
The following formula (3)
(wherein ^Z2 represents an arene ring;
^R4 represents a substituent; n4 represents an integer of 0 or more;
^A2 represents a linear or branched alkylene group.
The content of the compound represented by the formula (I) is 0.3% or less in terms of HPLC area percentage,
The following formula (4)
(In the formula, ^Z3a and ^Z3b each independently represent an arene ring,
^R5 represents a substituent; n5 represents an integer of 0 to 8;
R ^6a and R ^6b each independently represent a substituent; n6a and n6b each independently represent an integer of 0 or more;
^A3a and ^A3b each independently represent a linear or branched alkylene group, and m3a and m3b each independently represent an integer of 0 or greater. However, when both ^Z3a and ^Z3b are polycyclic arene rings, m3a and m3b cannot simultaneously be 1.
The content of the compound represented by the formula (I) is 0.01 to 10% in terms of HPLC area ratio,
A compound having a residual sulfur content of 10 ppm by mass or less. The content of the compound represented by the formula (2) is 0.2% or less, the content of the compound represented by the formula (3) is 0.05% or less, and residual sulfur is 1.5 mass ppm or less. The compound according to claim 1 . 3. The compound according to claim 1 , wherein the content of a compound in which one of m3a and m3b is 0 and the other is 1 in formula (4) is 0.01 to 1% by area percentage in HPLC. The compound according to any one of claims 1 to 3 , wherein the content of a compound in which, in formula (4), one of m3a and m3b is 1 and the other is 2 is 0.01 to 5% in terms of HPLC area percentage. The following formula (11)
(In the formula, Z ^8a and Z ^8b each independently represent an arene ring,
R ¹⁷ represents a substituent; n17 represents an integer of 0 to 8;
R ^18a and R ^18b each independently represent a substituent; n18a and n18b each independently represent an integer of 0 or more;
A ^8a to A ^8d each independently represent a linear or branched alkylene group, m8a and m8b each independently represent an integer of 0 or more, and m8c and m8d each independently represent an integer of 0 to 2, provided that m8c and m8d are not simultaneously 0.
The compound according to any one of claims 1 to 4 , wherein the content of the compound represented by the formula (I) is 0.01 to 10% in terms of area percentage by HPLC. A resin comprising the compound according to any one of claims 1 to 5 as a resin raw material. The resin according to claim 6 , which is a thermoplastic resin containing an ester bond in the main chain. 8. The resin according to claim 6, which is a thermoplastic resin containing a carbonate bond in the main chain. A method for suppressing discoloration of the compound represented by formula (1) in a molten state according to claim 1, by adjusting the content of the compound represented by formula (2) in claim 1 to 0.5% or less in terms of HPLC area percentage, the content of the compound represented by formula (3) in claim 1 to 0.3% or less in terms of HPLC area percentage, the content of the compound represented by formula (4) in claim 1 to 0.01 to 10% in terms of HPLC area percentage, and residual sulfur to 10 ppm by mass or less. A method for improving the glass transition temperature of a resin obtained by using the compound according to any one of claims 1 to 5 as a resin raw material. A method for reducing b* of a resin obtained by using the compound according to any one of claims 1 to 5 as a resin raw material.