JP7829857B2 - Method for producing cyclic polymers and cyclic polymers - Google Patents

Description

This invention relates to a method for producing cyclic polymers and to cyclic polymers themselves.

Cyclic polymers are polymer compounds that lack molecular ends. Because cyclic polymers have less inter-chain entanglement compared to linear polymers, their physical properties, such as viscosity, melting point, and glass transition temperature, are known to differ. As an example of utilizing the properties of cyclic polymers, Patent Document 1 discloses a hot-melt adhesive containing a hydrocarbon-based cyclic polymer. According to this document, hot-melt adhesives using linear α-olefin polymers have limited applications due to the high crystallinity and melting point of the α-olefin polymer, resulting in a very short time (less than a few seconds) between application and bonding. However, incorporating a hydrocarbon-based cyclic polymer improves creep resistance at high temperatures.

Two methods have been developed for synthesizing these cyclic polymers: end-linking and ring-expanding polymerization. End-linking involves synthesizing a linear polymer with reactive end groups, and then linking two reactive end groups via an intramolecular cyclization reaction. As an example of such a synthesis method, Patent Document 2 discloses a method for polymerizing ring-opening polymerizable monomers in a compressible fluid using an organic catalyst that does not contain metal atoms.

Ring expansion polymerization is a method for obtaining polymers by sequentially inserting monomers using a cyclic initiator. As an example of such a synthesis method, Patent Document 3 discloses a method for synthesizing macrocyclic polymers using a metal alkylidene complex as a catalyst for the ring insertion reaction of cyclic olefin monomers. Non-Patent Document 1 also reports the synthesis of cyclic polyesters by ring expansion polymerization of cyclic γ-butyrolactone using cyclic alkoxytin as an initiator.

International Publication No. 2018/012593 Japanese Patent Publication No. 2017-39863 Special Publication No. 2005-534777

Hans R. Kricheldop et. al., Macromol. Chem. Phys., 1998, 199, 273-282.

This invention has been made in view of the above circumstances, and aims to provide a novel method for producing cyclic polymers and a cyclic polymer obtained thereby.

The present inventors, after diligent research to solve the above problems, have found that 3H-benzothiazole-2-thione (BTT) or 2(3H)-benzothiazolon (BTO) or derivatives having the same skeleton undergo uniform cleavage of the dithioester or thioester portion upon light irradiation, as shown in the following chemical formulas (A) and (B), generating a pair of radicals within the molecule. When these radicals act in the presence of a monomer compound having an ethylenically unsaturated bond, the monomer compound is inserted between the pair of radicals, causing ring closure and the formation of a cyclic polymer, as shown in the following chemical formula (C). In other words, the chemical species shown in the following chemical formulas (A) and (B) act as photopolymerization initiators for cyclic polymer synthesis. This cyclic polymer undergoes repeated uniform cleavage and ring closure as long as light irradiation continues, and continues to polymerize in a living manner in the presence of the monomer compound. In the following chemical formulas (A) to (C), 3H-benzothiazole-2-thione (BTT) or 2(3H)-benzothiazolone (BTO) are given as photopolymerization initiators, and methyl methacrylate (MMA) is given as a monomer compound. However, these are merely examples for illustrative purposes, and the present invention is not limited to these compounds.

Specifically, the present invention provides the following:

(1) The present invention is a method for producing a cyclic polymer in which the monomer compound represented by the following general formula (2) and the compound represented by the following general formula (1) are irradiated with light at room temperature .
(In the above general formula (1), Z is a sulfur atom or an oxygen atom, and Ar is an aromatic ring which may have substituents, and the aromatic ring may be a fused ring.)
(In the above general formula (2), X is a hydrogen atom, a halogen atom, a cyano group, or an alkyl group having 1 to 5 carbon atoms, X is -(C=O) ^OR3 , ^-OR3 , or a carboxyl group, ^R2 is independently a hydrogen atom or a halogen atom, and ^R3 is a monovalent organic group.)

(2) The present invention also relates to a method for producing the cyclic polymer described in item (1), wherein Z is a sulfur atom.

(3) The present invention also relates to a method for producing the cyclic polymer described in item (1) or (2), wherein the compound represented by the general formula (2) is a (meth)acrylic acid ester.

(4) The present invention further relates to a method for producing a cyclic polymer according to any one of items (1) to (3), wherein the above-mentioned light irradiation is performed in the presence of a thioxanthone compound, a xanthone compound, anthracene compound, or an anthraquinone compound.

(5) The present invention also relates to a method for producing the cyclic polymer described in item (4), wherein the thioxanthone compound is 2-isopropylthioxanthone.

(6) The present invention is also a cyclic polymer represented by the following general formula (3).
(In the above general formula (3), Z is a sulfur atom or an oxygen atom, Ar is an aromatic ring which may have substituents and which may be a fused ring, ^R1 is a hydrogen atom, a halogen atom, a cyano group or an alkyl group having 1 to 5 carbon atoms, X is -(C=O) ^OR3 , ^-OR3 or a carboxyl group, ^R2 is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogen atom, ^R3 is a monovalent organic group, and n is an integer of 1 or more.)

(7) The present invention is also a cyclic polymer described in item (6), represented by the following general formula (3a).
(In the above general formula (3a), Z is a sulfur atom or an oxygen atom, Ar is an aromatic ring which may have substituents and which may be a fused ring, ^R1 is a hydrogen atom or a methyl group, ^R2 is independently a hydrogen atom or a methyl group, R is a monovalent organic group, and n is an integer of 1 or more.)

(8) The present invention also relates to the cyclic polymer described in item (6) or (7), wherein Z is a sulfur atom.

According to the present invention, a novel method for producing cyclic polymers and the cyclic polymers obtained thereby are provided.

Figure 1 is a chart of MALDI-TOF MS for the cyclic polymer (CP-MMA1) obtained in the examples. Figure 2 is a chart of MALDI-TOF MS for the cyclic polymer (CP-MMA2) obtained in the examples. Figure 3 is a chart of MALDI-TOF MS results for the cyclic polymer (CP-CHMA) obtained in the examples. Figure 4 is a chart of MALDI-TOF MS results for the cyclic polymer (CP-BzMA) obtained in the examples. Figure 5 is a chart of MALDI-TOF MS for the cyclic polymer (CP-MMA3) obtained in the examples.

The following describes one embodiment of the method for producing the cyclic polymer of the present invention, and one embodiment of the cyclic polymer of the present invention. However, the present invention is not limited to the following embodiments or examples, and can be implemented with appropriate modifications within the scope of the present invention.

<Method for manufacturing cyclic polymers>
First, one embodiment of the method for producing the cyclic polymer of the present invention will be described. The method for producing the cyclic polymer of the present invention is characterized by irradiating with light in the presence of a monomer compound represented by the following general formula (2) and a compound represented by the following general formula (1). By performing this production method, a cyclic polymer in which the above monomer compound is incorporated as a repeating unit is obtained. As already explained, the compound represented by the following general formula (1) undergoes uniform cleavage between the C-S bonds upon light irradiation, generating a pair of radicals within the molecule. These radicals act on the ethylenically unsaturated bonds of the (meth)acrylic acid ester, causing addition polymerization and increasing the molecular weight, while the pair of radicals present within the molecule bond together to cyclize the molecule. This uniform cleavage and cyclization are in equilibrium under light irradiation, and the compound represented by the following general formula (1) gradually increases its molecular weight by repeatedly going through the process of addition polymerization of the monomer compound after uniform cleavage and the process of cyclization to become a cyclic polymer. This polymerization process proceeds in a living manner and continues until all the monomer compounds in the system are consumed. The compound of the following general formula (1), which generates radicals upon light irradiation, acts as a photopolymerization initiator in the system of the present invention.

In the general formula (1) above, Z is either a sulfur atom or an oxygen atom. When Z is a sulfur atom, the compound represented by general formula (1) is 3H-arylthiazole-2-thion, and when Z is an oxygen atom, the compound represented by general formula (1) is 2(3H)-arylthiazolone. In both cases, the compound represented by general formula (1) undergoes uniform cleavage between the C-S bonds upon light irradiation, generating a pair of radicals within the molecule. The polymerization of the monomer compound by these radicals has already been explained.

In the general formula (1) above, Ar is an aromatic ring that may have substituents. Examples of aromatic rings include benzene rings and naphthalene rings. Examples of substituents that these aromatic rings may have include hydroxyl groups, amino groups, nitro groups, azi groups, halogen atoms, allyl groups, carboxyl groups, acyl groups, C2-C6 alkenyl groups, C2-C6 alkynyl groups, C1-C6 alkoxy groups, carboxyalkyl groups, alkyloxycarbonyl groups, 1-piperidylcarbonyl groups, and hydroxyalkyl groups. These substituents may be present one or more times.

The compounds represented by the above general formula (1) include 3H-benzothiazole-2-thion, 4-hydroxy-2(3H)-benzothiazolethion, 6-amino-2(3H)-benzothiazolethion, naphtho[1,2-d]thiazole-2(1H)-thion, naphtho[2,1-d]thiazole-2(3H)-thion, 6-hydroxymethyl-2(3H)-benzothiazolethion, naphtho[2,3-d]thiazole-2(3H)-thion, 6-ethynyl-2(3H)-benzothiazolethion, 5-amino-2(3H)-benzothiazolethion, 5-bromo-2(3H)-benzothiazolethion, and 5-fluoro-2(3H) -Benzothiazolethion, 2,3-dihydro-2-thioxo-6-benzothiazolecarbonitrine, 6-iodo-2(3H)-benzothiazolethion, 5-hydroxymethyl-2(3H)-benzothiazolethion, 5-ethenyl-2(3H)-benzothiazolethion, 7-amino-2(3H)-benzothiazolethion, 4-chloro-2(3H)-benzothiazolethion, 4-methoxy-2(3H)-benzothiazolethion, 4-bromo-2(3H)-benzothiazolethion, 7-hydroxymethyl-2(3H)-benzothiazolethion, 7-bromo-2(3H)-benzothiazolethion, 2,3-di Hydro-2-thioxo-6-benzothiazole carboxylic acid, 2,3-dihydro-2-thioxo-6-benzothiazole acetate, 6-nitro-2(3H)-benzothiazole thion, 4-phenyl-2(3H)-benzothiazole thion, 2,3-dihydro-2-thioxo-7-benzothiazole carboxylic acid, 2,3-dihydro-2-thioxo-6-benzothiazole carboxylic acid methyl ester, (2,3-dihydro-2-thioxo-5-benzothiazolyl)-1-piperidinylmethanone, 6-hydroxy-2(3H)-benzothiazolon, 5-hydroxy-2(3H)-benzothiazolon, 4-hydroxy-2(3H)-ben Examples include zothiazolon, 6-amino-2(3H)-benzothiazolon, 6-bromo-2(3H)-benzothiazolon, 6-fluoro-2(3H)-benzothiazolon, 5-bromo-2(3H)-benzothiazolon, 5-fluoro-2(3H)-benzothiazolon, 5-ethenyl-2(3H)-benzothiazolon, 2,3-dihydro-2-oxo-6-benzothiazole carboxylic acid, 5-acetyl-2(3H)-benzothiazolon, 6-azido-2(3H)-benzothiazolon, 5-nitro-2(3H)-benzothiazolon, etc., among which 3H-benzothiazole-2-thion is preferred.

A preferred example of the compound represented by the above general formula (1) is the one represented by the following general formula (1a). The compound represented by the following general formula (1a) is one of the compounds represented by the above general formula (1) in which Ar is a benzene ring. In the following general formula (1a), Z is either a sulfur atom or an oxygen atom, and among these, a sulfur atom is preferred for Z.

The monomer compound is a component used for increasing molecular weight through addition polymerization by radicals generated by the uniform cleavage of the general formula (1) above, and is represented by the following general formula (2).

In the above general formula (2), ^R1 is a hydrogen atom, a halogen atom, a cyano group, or an alkyl group having 1 to 5 carbon atoms, among which a hydrogen atom or a methyl group is preferred. In the above general formula (2), the two ^R2s are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogen atom, among which it is preferred that both ^R2s are hydrogen atoms. In the above general formula (2), X is -(C=O) ^OR3 , ^-OR3 , a carboxyl group, a hydrogen atom, an ethenyl group, a cyano group, an alkyl group having 1 to 6 carbon atoms, a substituted phenyl group, a halogen atom, an aminocarbonyl group, a monoalkylaminocarbonyl group, a dialkylaminocarbonyl group, an alkylcarbonyloxy group, or a nitro group. ^R3 is a monovalent organic group, and examples of such monovalent organic groups include C1-C12 alkyl groups which may be branched, C1-C18 cycloalkyl groups which may be fused rings, aryl groups, aralkyl groups, aryloxy groups, alkylaryloxy groups, fluorenyl groups, carbazolyl groups, polysylsesquioxanyl groups, etc. These monomer compounds may be used individually or in combination of two or more.

(Meth)acrylic acid esters are preferred examples of monomers represented by the above general formula (2). In this invention, the term "(meth)acrylic acid ester" means acrylic acid ester and/or methacrylic acid ester. (Meth)acrylic acid esters are compounds also called (meth)acrylates. In this invention, the term "(meth)acrylate" means acrylate and/or methacrylate. Examples of such compounds include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, isobutyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate, isobornyl (meth)acrylate, and adamantyl (meth)acrylate. Examples include acrylates, cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, benzyl (meth)acrylate, phenyl (meth)acrylate, phenylbenzyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, phenoxytetraethylene glycol (meth)acrylate, nonylphenoxyethyl (meth)acrylate, phenoxybenzyl (meth)acrylate, etc. Among these, methyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, fluorenyl (meth)acrylate, carbazolyl (meth)acrylate, polysilsesquioxanyl (meth)acrylate, etc. These (meth)acrylates may be used individually or in combination of two or more.

Furthermore, when polymerizing monomer compounds represented by general formula (2) and compounds represented by general formula (1) by light irradiation, it is preferable to use a sensitizer. Examples of such sensitizers include thioxanthone compounds, xanthone compounds, anthracene compounds, and anthraquinone compounds. The presence of such sensitizers promotes the polymerization reaction by light irradiation, allowing for a higher conversion rate of the monomer compound compared to the case without sensitizers, even with the same reaction time.

Examples of thioxanthone compounds include 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, and 1-chloro-4-propoxythioxanthone. Examples of xanthone compounds include 2-isopropylxanthone, 4-isopropylxanthone, 2,4-diethylxanthone, 2,4-dichloroxanthone, and 1-chloro-4-propoxyxanthone. Among these, 2-isopropylthioxanthone is a preferred example. These thioxanthone and xanthone compounds may be used individually or in combination of two or more.

By irradiating a solution containing a monomer compound represented by general formula (2) and a compound represented by general formula (1) with light, a polymerization reaction occurs, synthesizing a cyclic polymer. Examples of solvents used in this process include toluene, tetrahydrofuran, 1,4-dioxane, acetonitrile, and N-methylpyrrolidone. Among these, 1,4-dioxane is preferred from the viewpoint of suppressing side reactions in which multiple compounds represented by general formula (1) are incorporated into a single cyclic monomer.

Light sources used for irradiation include those containing ultraviolet light with an absorption wavelength of approximately 370 nm or less, which is the absorption wavelength of the compound represented by general formula (1). Examples of such light sources include ultraviolet light-emitting diodes (UV-LEDs), xenon lamps, metal halide lamps, and high-pressure mercury lamps.

The molar ratio of the monomer compound represented by general formula (2) and the compound represented by general formula (1) can be appropriately determined according to the desired molecular weight of the resulting cyclic polymer. Furthermore, since the cyclic polymer incorporating the compound represented by general formula (1) undergoes further uniform cleavage upon light irradiation, forming radicals, further molecular weight increases can be achieved by adding more monomer compounds to the solution containing these radicals and irradiating with light. Additionally, utilizing these properties, a cyclic block copolymer can be prepared by forming a cyclic polymer using only one monomer, stopping the light irradiation, adding another monomer, and then resuming the light irradiation.

<Platinum polymer>
Next, the cyclic polymer obtained by the method for producing the cyclic polymer of the present invention described above will be explained. This cyclic polymer is also one of the present inventions. The cyclic polymer of the present invention is a molecule that exhibits a cyclic shape rather than a linear shape like general polymers, and therefore exhibits unique properties not found in linear polymers, based on its molecular shape. Specifically, the cyclic polymer of the present invention has different physical properties such as viscosity, melting point, and glass transition temperature compared to linear polymers.

The cyclic polymer of the present invention is a compound represented by the following general formula (3). This cyclic polymer may be a cyclic polymer formed by the polymerization of a single monomer compound, or it may be a cyclic random copolymer or a cyclic block copolymer formed by the polymerization of two or more polymers. The method for preparing the cyclic block copolymer is as previously described.

In the general formula (3) above, Ar is an aromatic ring that may have substituents. Examples of aromatic rings include benzene rings and naphthalene rings. Examples of substituents that these aromatic rings may have include hydroxyl groups, amino groups, nitro groups, azi groups, halogen atoms, allyl groups, carboxyl groups, acyl groups, C2-C6 alkenyl groups, C2-C6 alkynyl groups, C1-C6 alkoxy groups, carboxyalkyl groups, alkyloxycarbonyl groups, 1-piperidylcarbonyl groups, and hydroxyalkyl groups. These substituents may be present one or more times.

In the above general formula (3), Z is a sulfur atom or an oxygen atom, and among these, a sulfur atom is preferred as Z. Also, in the above general formula (3), ^R1 is a hydrogen atom, a halogen atom, a cyano group, or an alkyl group having 1 to 5 carbon atoms, and among these, a hydrogen atom or a methyl group is preferred. In the above general formula (3), the two ^R2s are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogen atom. In the above general formula (3), X is -(C=O) ^OR3 , ^-OR3 , a carboxyl group, a hydrogen atom, an ethenyl group, a cyano group, an alkyl group having 1 to 6 carbon atoms, a substituted phenyl group, a halogen atom, an aminocarbonyl group, a monoalkylaminocarbonyl group, a dialkylaminocarbonyl group, an alkylcarbonyloxy group, or a nitro group. ^R3 is a monovalent organic group, and examples of such monovalent organic groups include C1-C12 alkyl groups which may have branches, C1-C18 cycloalkyl groups which may be fused rings, aryl groups, aralkyl groups, aryloxy groups, alkylaryloxy groups, etc.

In the general formula (3) above, n represents the number of repeats in the monomer structure, which is the repeating unit. n is an integer of 1 or more, preferably an integer of 5 or more.

A preferred example of the cyclic polymer represented by the above general formula (3) is the one represented by the following general formula (3a).

In the above general formula (3a), ^R1 , Z, and n are the same as those in the above general formula (3), and the two ^R2s are each independently a hydrogen atom or a methyl group. Also, in general formula (3a), R is a monovalent organic group. Examples of such monovalent organic groups include those similar to ^R3 in the above general formula (3).

A more preferred example of the cyclic polymer represented by the above general formula (3) is the one represented by the following general formula (3b).

The cyclic polymer represented by the above general formula (3b) is obtained by polymerizing a (meth)acrylic acid ester using 3H-benzothiazole-2-thion as a photopolymerization initiator. In the above general formula (3b), ^R1 , R, and n are the same as those in the above general formula (3a).

The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way to the following examples.

• Synthesis of cyclic polymers by photopolymerization 1 (CP-MMA1)

3H-benzothiazole-2-thion (BTT, 0.167 g, 1.00 mmol), 1,4-dioxane (1.00 mL), and methyl methacrylate (MMA, 1.00 g, 10.0 mmol) were added to a 5 mm diameter screw-cap sample tube and stirred to form a homogeneous solution. The solution was then frozen and degassed four times, and the solution was irradiated with ultraviolet light from a UV-LED (805 mW/ ^cm² at 365 nm) at a distance of approximately 1 cm from the solution for 4 hours at room temperature. After the light irradiation was completed, the reaction solution was dried under reduced pressure to obtain the product, cyclic polymethyl methacrylate (CP-MMA1), as a transparent viscous solid (conversion rate 39%, yield 0.267 g, yield 23%).

The physical properties of the product are as follows:
FT-IR(KBr, ^cm⁻¹ ): 2995 (ν _{C-H aromatic} ), 2950 (ν _{C-H alkane} ), 1733 (ν _{C=O carbonyl} ), 1455 (ν _{C=S thioamide} ), 731 (ν _{C-S sulfide} ).
¹ H-NMR (500 MHz, CDCl ₃ ) δ (ppm): 8.03 (br, 1.00 H, H _a ), 7.88 (br, 0.994 H, H _d ), 7.49 (br, 1.04 H, H _c ), 7.40 (br, 1.11 H, H _b ), 3.76-3.27 (br, 13.72H, H _h ) 1.88-1.56 (br, 32.46H, H _f ) 1.13-0.837 (br, 17.41H, H _g ).
GPC (DMF, Polystyrene std, RI) Mn=1190, Mw/Mn=2.73

Mass spectrometry was performed on CP-MMA1 obtained using the above procedure by MALDI-TOF MS (ionizing agent: silver trifluoroacetate). The results are shown in Figure 1. Figure 1 is a MALDI-TOF MS chart for the cyclic polymer (CP-MMA1) obtained in the example. In Figure 1, the peaks marked with circles correspond to the molecular weight of BTT + molecular weight of MMA × n + mass of silver ions [(BTT + nMMA) + Ag] ⁺ .

As shown in Figure 1, the intervals between each peak coincide with the molecular weight of MMA ( _MMA = 100.12), and since each of these peaks corresponds to the molecular weight (and mass of silver ions) of the cyclic CP-MMA containing the BTT1 molecule, it can be seen that the product has a cyclic structure. Table 1 shows the degree of polymerization (n), the measured value of [(BTT + nMMA) + Ag] ⁺ by MS, and the calculated value for each peak corresponding to the cyclic polymers with a degree of polymerization of 28 to 32 in Figure 1.

• Synthesis of cyclic polymers by photopolymerization 2 (CP-MMA2)

BTT (0.167 g, 1.00 mmol), 1,4-dioxane (1.00 mL), and methyl methacrylate (MMA, 1.00 g, 10.0 mmol) were added to a 5 mm diameter screw-top sample tube and stirred to form a homogeneous solution. The solution was then frozen and degassed four times, and the solution was irradiated with ultraviolet light from a UV-LED (919 mW/ ^cm² at 365 nm) at a distance of approximately 1 cm from the solution for 6 hours at room temperature. After the light irradiation was completed, the reaction solution was dried under reduced pressure to obtain the product, cyclic polymethyl methacrylate (CP-MMA2), as a transparent viscous solid (conversion rate 65%, yield 1.01 g, yield 86%).

The physical properties of the product are as follows:
FT-IR(KBr, ^cm⁻¹ ): 2996 (ν _{C-H aromatic} ), 2950 (ν _{C-H alkane} ), 1733 (ν _{C=O carbonyl} ), 1486 (ν _{C-C aromatic} ), 1456 (ν _{C=S thioamide} ), 758 (ν _{C-S sulfide} ).
¹ H-NMR (500 MHz, CDCl ₃ ) δ (ppm): 8.03 (br, 1.00 H, H _a ), 7.88 (br, 0.984 H, H _d ), 7.49 (br, 1.02 H, H _c ), 7.40 (br, 1.03 H, H _b ), 3.76-3.27 (br, 22.50H, H _h ) 1.88-1.57 (br, 25.31H, H _f ) 1.02-0.837 (br, 11.54H, H _g ).
GPC (DMF, Polystyrene std, RI) Mn=1360, Mw/Mn=2.36

Mass spectrometry was performed on the CP-MMA2 obtained using the above procedure by MALDI-TOF MS (ionizing agent: silver trifluoroacetate). The results are shown in Figure 2. Figure 2 is a MALDI-TOF MS chart for the cyclic polymer (CP-MMA2) obtained in the example. In Figure 2, the peaks marked with circles correspond to the molecular weight of BTT + molecular weight of MMA × n + mass of silver ions [(BTT + nMMA) + Ag] ⁺ .

As shown in Figure 2, the intervals between each peak coincide with the molecular weight of MMA ( _MMA = 100.12), and since each of these peaks corresponds to the molecular weight (and mass of silver ions) of the cyclic CP-MMA containing the BTT1 molecule, it can be seen that the product has a cyclic structure. Table 2 shows the degree of polymerization (n), the measured value of [(BTT + nMMA) + Ag] ⁺ by MS, and the calculated value for each peak corresponding to the cyclic polymers with a degree of polymerization of 13 to 17 in Figure 2.

• Synthesis of cyclic polymers by photopolymerization 3 (CP-CHMA)

BTT (0.167 g, 1.00 mmol), 1,4-dioxane (1.00 mL), and cyclohexyl methacrylate (CHMA, 1.68 g, 10.0 mmol) were added to a 5 mm diameter screw-cap sample tube and stirred to form a homogeneous solution. The solution was then frozen and degassed four times, and the solution was irradiated with ultraviolet light from a UV-LED (907 mW/ ^cm² at 365 nm) at a distance of approximately 1 cm from the solution for 6 hours at room temperature. After the light irradiation was completed, the reaction solution was dried under reduced pressure to obtain the product, cyclic polycyclohexyl methacrylate (CP-CHMA), as a yellow viscous solid (conversion rate 92%, yield 0.775 g, yield 66%).

The physical properties of the product are as follows:
FT-IR(KBr, ^cm⁻¹ ): 2936 (ν _{C-H aromatic} ), 2958 (ν _{C-H alkane} ), 1725 (ν _{C=O carbonyl} ), 1450 (ν _{C=S thioamide} ), 759 (ν _{C-S sulfide} ).
¹ H-NMR (500 MHz, CDCl ₃ ) δ (ppm): 8.01 (br, 1.00 H, H _a ), 7.88 (br, 0.995 H, H _d ), 7.47 (br, 1.07 H, H _c ), 7.38 (br, 1.07 H, H _b ), 4.87-3.27 (br, 8.76H, H _f ), 2.50-0.924 (br, 103.27H, H _g,h ).
GPC (DMF, Polystyrene std, RI) Mn=1140, Mw/Mn=1.95

Mass spectrometry was performed on the CP-CHMA obtained using the above procedure by MALDI-TOF MS (ionizing agent: silver trifluoroacetate). The results are shown in Figure 3. Figure 3 is a MALDI-TOF MS chart for the cyclic polymer (CP-CHMA) obtained in the example. In Figure 3, the peaks marked with circles correspond to the molecular weight of BTT + molecular weight of CHMA × n + mass of silver ions [(BTT + nCHMA) + Ag] ⁺ .

As shown in Figure 3, the intervals between each peak coincide with the molecular weight of CHMA (M _CHMA = 168.24), and since each of these peaks corresponds to the molecular weight (and mass of silver ions) of cyclic CP-CHMA containing BTT1 molecules, it can be seen that the product has a cyclic structure. Table 3 shows the degree of polymerization (n), the measured value of [(BTT + nCHMA) + Ag] ⁺ by MS, and its calculated value for each peak corresponding to the cyclic polymers with degrees of polymerization 8 to 12 in Figure 3.

• Synthesis of cyclic polymers by photopolymerization 4 (CP-BzMA)

BTT (0.167 g, 1.00 mmol), 1,4-dioxane (1.00 mL), and benzyl methacrylate (BzMA, 1.76 g, 10.0 mmol) were added to a 5 mm diameter screw-top sample tube and stirred to form a homogeneous solution. The solution was then frozen and degassed four times, and the solution was irradiated with ultraviolet light from a UV-LED (918 mW/ ^cm² at 365 nm) at a distance of approximately 1 cm from the solution for 6 hours at room temperature. After the light irradiation was completed, the reaction solution was dried under reduced pressure to obtain the product, cyclic polybenzyl methacrylate (CP-BzMA), as a yellow viscous solid (conversion rate 81%, yield 0.526 g, yield 27%).

The physical properties of the product are as follows:
FT-IR(KBr, ^cm⁻¹ ): 2952 (ν _{C-H aromatic} ), 1728 (ν _{C=O carbonyl} ), 1455 (ν _{C=S thioamide} ), 751 (ν _{C-S sulfide} ).
¹ H-NMR (500 MHz, CDCl ₃ ) δ (ppm): 7.98 (br, 1.00 H, H _a ), 7.83 (br, 1.30 H, H _d ), 7.46 (br, 2.03 H, H _{c, b} ), 7.28 (br, 46.93 H, H _i ), 5.16-4.87 (br, 26.23H, H _h ) 1.89-1.40 (br, 34.39H, H _f ) 1.13-0.837 (br, 34.48H, H _g ).
GPC (DMF, Polystyrene std, RI) Mn=3120, Mw/Mn=2.03

Mass spectrometry was performed on the CP-BzMA obtained using the above procedure by MALDI-TOF MS (ionizing agent: silver trifluoroacetate). The results are shown in Figure 4. Figure 4 is a MALDI-TOF MS chart for the cyclic polymer (CP-BzMA) obtained in the example. In Figure 4, the peaks marked with circles correspond to the molecular weight of BTT + molecular weight of BzMA × n + mass of silver ions [(BTT + nBzMA) + Ag] ⁺ .

As shown in Figure 4, the interval between each peak coincides with the molecular weight of BzMA (M _BzMA = 176.22), and since each of these peaks corresponds to the molecular weight (and mass of silver ions) of the cyclic CP-BzMA containing the BTT1 molecule, it can be seen that the product has a cyclic structure. Table 4 shows the degree of polymerization (n), the measured value of [(BTT + nBzMA) + Ag] ⁺ by MS, and its calculated value for each peak corresponding to the cyclic polymers with degrees of polymerization 5 to 9 in Figure 4.

• Synthesis of cyclic polymers by photopolymerization 5 (CP-MMA3)

In a 5 mm diameter screw-top sample tube, BTT (0.167 g, 1.00 mmol), 1,4-dioxane (1.00 mL), 2-isopropylthioxanthone (ITX, 0.0128 g, 0.05 mmol), and methyl methacrylate (MMA, 1.00 g, 10.0 mmol) were added and stirred to form a homogeneous solution. The solution was then frozen and degassed four times, and the solution was irradiated with ultraviolet light from a UV-LED (939 mW/ ^cm² at 365 nm) at a distance of approximately 1 cm from the solution for 4 hours at room temperature. After light irradiation, the reaction solution was dried under reduced pressure to obtain the product, cyclic polymethyl methacrylate (CP-MMA3), as a transparent viscous solid (conversion rate 78%, yield 0.407 g, yield 35%).

The physical properties of the product are as follows:
FT-IR(KBr, ^cm⁻¹ ): 2995 (ν _{C-H aromatic} ), 2950 (ν _{C-H alkane} ), 1733 (ν _{C=O carbonyl} ), 1486 (ν _{C-C aromatic} ), 1456 (ν _{C=S thioamide} ), 758 (ν _{C-S sulfide} ).
¹ H-NMR (500 MHz, CDCl ₃ ) δ (ppm): 8.03 (br, 1.00 H, H _a ), 7.88 (br, 1.14 H, H _d ), 7.51 (br, 1.17 H, H _c ), 7.41 (br, 1.53 H, H _b ), 3.76-3.29 (br, 32.17H, H _h ) 2.18-1.56 (br, 20.45H, H _f ) 1.44-0.837 (br, 46.35H, H _h ).
GPC (DMF, Polystyrene std, RI) Mn=1630, Mw/Mn=2.40

Mass spectrometry was performed on the CP-MMA3 obtained using the above procedure by MALDI-TOF MS (ionizing agent: silver trifluoroacetate). The results are shown in Figure 5. Figure 5 is a MALDI-TOF MS chart for the cyclic polymer (CP-MMA3) obtained in the example. In Figure 5, the peaks marked with circles correspond to the molecular weight of BTT + molecular weight of MMA × n + mass of silver ions [(BTT + nMMA) + Ag] ⁺ .

As shown in Figure 5, the intervals between each peak coincide with the molecular weight of MMA ( _MMA = 100.12), and since each of these peaks corresponds to the molecular weight (and mass of silver ions) of the cyclic CP-MMA containing the BTT1 molecule, it can be seen that the product has a cyclic structure. Table 5 shows the degree of polymerization (n), the measured value of [(BTT + nMMA) + Ag] ⁺ by MS, and the calculated value for each peak corresponding to the cyclic polymers with degrees of polymerization 5 to 9 in Figure 5.

Claims (8)

A method for producing a cyclic polymer in which the monomer compound is incorporated as a repeating unit, characterized by irradiating with light at room temperature in the presence of a monomer compound represented by the following general formula (2) and a compound represented by the following general formula (1).
(In the above general formula (1), Z is a sulfur atom or an oxygen atom, and Ar is an aromatic ring which may have substituents, and the aromatic ring may be a fused ring.)
(In the above general formula (2), ^R1 is a hydrogen atom, a halogen atom, a cyano group, or an alkyl group having 1 to 5 carbon atoms; X is -(C=O) ^OR3 , ^-OR3 , or a carboxyl group; ^R2 is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogen atom; and ^R3 is a monovalent organic group.) A method for producing a cyclic polymer according to claim 1, wherein Z is a sulfur atom. A method for producing a cyclic polymer according to claim 1 or 2, wherein the compound represented by the general formula (2) is a (meth)acrylic acid ester. Furthermore, the method for producing a cyclic polymer according to any one of claims 1 to 3, wherein the light irradiation is performed in the presence of a thioxanthone compound, a xanthone compound, anthracene compound, or an anthraquinone compound. The method for producing a cyclic polymer according to claim 4, wherein the thioxanthone compound is 2-isopropylthioxanthone. A cyclic polymer represented by the following general formula (3).
(In the above general formula (3), Z is a sulfur atom or an oxygen atom, Ar is an aromatic ring which may have substituents and which may be a fused ring, ^R1 is a hydrogen atom, a halogen atom, a cyano group or an alkyl group having 1 to 5 carbon atoms, X is -(C=O) ^OR3 , ^-OR3 or a carboxyl group, ^R2 is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogen atom, ^R3 is a monovalent organic group, and n is an integer of 1 or more.) The cyclic polymer according to claim 6, represented by the following general formula (3a).
(In the above general formula (3a), Z is a sulfur atom or an oxygen atom, Ar is an aromatic ring which may have substituents and which may be a fused ring, ^R1 is a hydrogen atom or a methyl group, ^R2 is independently a hydrogen atom or a methyl group, R is a monovalent organic group, and n is an integer of 1 or more.) The cyclic polymer according to claim 6 or 7, wherein Z is a sulfur atom.