JP4593638B2 - Method for producing ester solvent - Google Patents

Description

  The present invention relates to a high-boiling ester solvent used for electronic materials such as a semiconductor resist, a color resist, and an inkjet ink for LCD, and the like, and a method for producing the same.

  The production of ester solvents by the dehydration reaction of alcohols and acids is generally carried out in the presence of an acid catalyst, and in order to produce high purity ester solvents, distillation purification is performed after the reaction is completed. Is common. However, in the case of a high-boiling ester, an increase in acid content due to thermal deterioration during distillation (such as thermal decomposition of the ester) becomes a problem. In a system in which an acid catalyst is present, thermal decomposition of the product is remarkable, and in order to efficiently produce a high purity ester solvent, it is necessary to remove the acid catalyst before distillation. Conventionally, as a method for removing an acid catalyst, a method of neutralizing with an alkali metal hydroxide or the like has been generally used (for example, cited reference 1). However, in such a method, the alkali metal used for neutralization may be mixed into the product. When used as a solvent in electronic materials such as semiconductor resists, color resists, and inkjet inks for LCDs, it is essential to manage the metal content in the ppb order. The demand for reducing the amount and acid content could not be sufficiently met.

Japanese Patent Laid-Open No. 5-112489

An object of the present invention is to provide an alkali metal such as sodium and a high-boiling ester solvent having a very low acid content that can be used in the field of electronic materials that require high-purity quality, and an efficient industrial production method thereof. It is.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have distilled off the low-boiling components without neutralizing the esterification reaction crude liquid before distillation, A product with extremely low acid content is obtained by distilling the ester solvent more, especially by concentrating the low boiling acid content at the top of the column by refluxing during distillation and distilling the product by the side cut method in this state. In addition, since neutralization treatment is not performed, contamination of alkali metal such as sodium, which has been a problem in the production method including the conventional neutralization treatment step, can be eliminated, the alkali metal content and The present inventors have found that a high-purity, high-boiling ester solvent having an extremely low acid content can be obtained.

The present invention provides a mineral acid, obtained by p- toluenesulfonic acid, and the alcohol and carboxylic acid to S. Te Le reaction with boron trifluoride under at least one acid catalyst present is selected from (BF ₃₎ The esterification reaction crude liquid is purified by distillation using a distillation tower, and a batch distillation apparatus in which the distillation can is connected to the bottom of the distillation tower, The reaction crude liquid obtained by the esterification reaction is subjected to distillation purification without neutralization treatment, and after distilling off the low-boiling components, the ester solvent from the side cut line provided in the middle part of the distillation column A process for producing an ester solvent is provided.

  Examples of the ester solvent that can be produced by the production method of the present invention include ester solvents that have a boiling point of 120 to 300 ° C. at normal pressure.

In the manufacturing method of an ester solvent of the present invention, the alcohol used as a raw material, for example, cyclohexanol, 1,3-butylene glycol, dipropylene glycol monomethyl ether, propylene glycol, 1,6-hexanediol like Examples of the carboxylic acid include acetic acid.

The ester-based solvent production method of the present invention includes, for example, a distillation can capable of reacting an alcohol and a carboxylic acid therein, a distillation column whose bottom is connected to the distillation can, and a middle portion of the distillation column. In a facility having a side cut line, a decanter connected to the top of the distillation column, and a vacuum unit capable of adjusting the pressure of the top of the distillation column, connected to the top of the distillation column during the reaction of alcohol and carboxylic acid The aqueous layer and the organic layer are separated with the decanter, the aqueous layer is removed from the system, and the organic layer is allowed to flow to the top of the distillation column while allowing the esterification reaction to proceed. During distillation purification, after removing low-boiling components from the top of the distillation column, the ester solvent is distilled off from the distillation column side cut line while refluxing and concentrating the remaining low-boiling components at the top of the column. It can be carried out by.

Method for producing ester-based solvent of the present invention is also from a side cut line provided at an intermediate portion of the steam column can be sodium content is distilled to ester solvent is less than 2 wt ppb. In the present specification, in addition to the above-mentioned invention, an ester solvent for distilling and purifying an esterification reaction crude liquid obtained by esterifying an alcohol and a carboxylic acid in the presence of an acid catalyst using a distillation tower The reaction crude liquid is subjected to distillation purification without neutralizing the reaction crude liquid, and after distilling off low-boiling components, the ester solvent is distilled off from the side cut line provided in the middle part of the distillation column. A method for producing an ester solvent to be produced is also described.

According to the present invention, since the neutralization treatment of the esterification reaction crude liquid is not performed, the mixing of the alkali metal such as sodium due to the neutralization treatment does not occur in the ester solvent. Accordingly, an ester solvent having an extremely small content of alkali metal such as sodium can be obtained. Moreover, after distilling off the low-boiling components in the esterification reaction crude liquid, the product is distilled by side-cutting, so that the acid content in the ester solvent after distillation purification is extremely small.
Further, since the neutralization treatment is not performed, the refining operation is simple, and an ester solvent having an extremely low content of alkali metals such as sodium and impurities such as acid components can be efficiently produced.

[Method for producing ester solvent]
Below, the manufacturing method of the ester solvent of this invention is demonstrated with reference to drawings as needed. FIG. 1 is a schematic view showing an example of an apparatus (batch distillation apparatus) that can be suitably used in the method for producing an ester solvent of the present invention. If such a batch distillation apparatus is used, reaction and subsequent distillation purification can be performed efficiently. In FIG. 1, 1 is a distillation can (hereinafter referred to as a distillation can) capable of reacting alcohol and acid inside, 2 is a distillation column, 3 is a vacuum unit, 4 is a decanter, 4-1. Represents an aqueous layer in the decanter, and 4-2 represents an organic layer in the decanter. 5 indicates a pump, and 6 and 7 indicate heat exchangers (condensers). In the figure, A to H each represent a line. The distillation can 1 is connected to the bottom of the distillation tower 2 by line B. A side cut line H is provided at the middle stage of the distillation column 2, and a decanter 4 and a vacuum unit 3 capable of adjusting the pressure inside the distillation column 2 are connected to the top of the column.

[Esterification reaction]
Below, the manufacturing method of the ester solvent of this invention is demonstrated in detail by making into an example the case where the ester solvent is manufactured using the apparatus (batch type distillation apparatus) shown in FIG. In addition, when using a batch type distillation apparatus, it is preferable to use as the distillation column 2 a distillation column having 5 to 50 theoretical plates. The raw material alcohol, carboxylic acid, acid catalyst, and, if necessary, an azeotropic solvent to be described later are supplied into the distillation can 1 through the line A and subjected to esterification reaction.

  The alcohol is not particularly limited, but examples thereof include aliphatic monoalcohols such as cyclohexanol, ethanol, propanol and butanol, and aliphatic polyhydric alcohols such as 1,3-butylene glycol, propylene glycol and 1,6-hexanediol. And glycol ethers such as ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, propylene glycol monomethyl ether, and dipropylene glycol monomethyl ether. Among these, alcohol having a boiling point of 120 to 300 ° C. at normal pressure can be preferably used. Examples of such alcohol include cyclohexanol, 1,3-butylene glycol, dipropylene glycol monomethyl ether, propylene glycol, 1 , 6-hexanediol.

  Examples of the carboxylic acid include aliphatic saturated carboxylic acids such as formic acid, acetic acid, propionic acid, and butanoic acid; aliphatic unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid; oxalic acid, malonic acid, succinic acid, Examples thereof include polyvalent carboxylic acids such as glutaric acid and adipic acid; aromatic carboxylic acids such as benzoic acid and phthalic acid. Of these, saturated aliphatic carboxylic acids such as acetic acid, propionic acid, and butanoic acid are preferably used, and acetic acid is particularly preferably used.

When cyclohexanol is used as the alcohol and acetic acid is used as the acid, cyclohexanol acetate is obtained as the ester solvent. When 1,3-butylene glycol and acetic acid are respectively used, the ester solvent is used. 1,3-diacetoxybutane was obtained, and when dipropylene glycol monomethyl ether and acetic acid were respectively employed, dipropylene glycol methyl ether acetate was obtained as an ester solvent, and propylene glycol and acetic acid were respectively employed. In this case, propylene glycol diacetate is obtained as the ester solvent, and 1,6-diacetoxyhexane is obtained as the ester solvent when 1,6-hexanediol and acetic acid are respectively employed.

As the acid catalyst, any known or commonly used acid catalyst usually used for esterification reaction can be used, and is not particularly limited. For example, mineral acid such as sulfuric acid, organic acid such as p-toluenesulfonic acid (sulfonic acid) And Lewis acids such as BF ₃ can be exemplified. In addition, you may add the component (azeotropic solvent) azeotroped with water like hexane, cyclohexane, benzene, toluene, xylene, butyl acetate, isobutyl acetate at the time of reaction.

  The blending ratio of the raw materials is not particularly limited, and a blending ratio that is usually used for producing an ester solvent by a reaction between an alcohol and a carboxylic acid can be applied. For example, the acid can be selected from the range of about 0.8 to 10 times mol, preferably about 0.8 to 5 times mol of the alcohol. Moreover, the usage-amount of an acid catalyst can be selected from the range of 0.01 to 10 weight% with respect to an acid, for example.

  The reaction temperature, pressure, time and the like can be appropriately set depending on the types of alcohol and acid as raw materials, and are not particularly limited. For example, as a raw material alcohol, an alcohol having a boiling point of 120 to 300 ° C. at normal pressure, such as cyclohexanol, 1,3-butylene glycol, dipropylene glycol monomethyl ether, propylene glycol, 1,6-hexanediol, etc. is used. If acetic acid is used as the acid, the reaction temperature is preferably 80 to 180 ° C., the reaction pressure is 1 kPa to normal pressure, and the reaction time is preferably about 5 to 20 hours. As the distillation can 1, what can manage these temperatures and pressures may be used.

  During the reaction, the pressure at the top of the distillation column 2 is 1 kPa. A to normal pressure, preferably 40 kPa. Before and after A (for example, 35 to 45 kPa.A, particularly 38 to 42 kPa.A), the temperature is adjusted to 80 to 200 ° C., preferably 80 to 170 ° C. During the esterification reaction, the distillate circulates in the line C represented by the broken line in FIG. In the decanter 4 connected to the top of the distillation column 2, the distillate is separated into an aqueous layer containing water generated by the progress of the esterification reaction and an organic layer composed of unreacted raw materials and an azeotropic solvent. The aqueous layer is extracted from the line D to the outside, and the organic layer is sent again to the top of the distillation column 2 by the pump 5, and the organic layer is refluxed until the esterification reaction is completed. In addition, it can be judged that esterification reaction was completed by the production | generation of water stopping.

[Distillation purification]
In the present invention, the esterification reaction crude liquid obtained as described above is distilled and purified without neutralization to produce an ester solvent, but the distillation column 2 has side cut lines H before and after the middle stage of the column. Is provided. The position where the side cut line H is provided can be appropriately set in the middle part of the distillation column 2 excluding the tower top and the tower bottom depending on the conditions, but in the theoretical stage, for example, 1/5 to 4/5, preferably 1 / It can be set to 4 to 3/4, particularly preferably 1/3 to 2/3.

  In the distillation purification, first, in addition to the remaining low-boiling components such as unreacted carboxylic acid, unreacted alcohol and azeotropic solvent, low-boiling components generated by thermal decomposition during distillation are distilled from the top of the distillation column 2. Leave. At the time of distillation purification, the temperature and pressure of the distillation can 1 are, for example, 80 to 180 ° C. and 1 kPa. It can be selected from the range of A to normal pressure. Usually, a component having a relatively low boiling point (such as an azeotropic solvent and a carboxylic acid) is distilled first among low boiling components, and thereafter alcohols having a relatively high boiling point are distilled. Accordingly, at the beginning of distillation, distillation is performed at a low reflux ratio (for example, total distillation to 5, preferably 0.1 to 3, particularly 0.2 to 1), and when the alcohols are distilled, the reflux ratio is increased. (For example, 0.5 to 20, preferably 3 to 15, particularly 8 to 12) When distillation is performed, highly accurate distillation can be performed efficiently. Further, during distillation purification, the internal temperature of the distillation can 1 is kept at a predetermined temperature or lower (for example, 180 ° C. or lower, preferably 160 ° C. or lower, more preferably 150 ° C. or lower), and the internal pressure of the distillation column 2 is lowered stepwise. Is preferred. The distilled low boiling point component can be removed from the line G, and a part thereof can be refluxed to the distillation column 2 through the line F.

  After most of the low-boiling components in the esterification reaction crude liquid have been distilled off (for example, 95% by weight or more, preferably 99% by weight or more), the remaining low-boiling components are concentrated at the top of the column by refluxing. The ester solvent is distilled from the side cut line H provided in the middle part of the distillation column. When distilling the ester solvent from the side cut line H, if there are too many low-boiling components remaining in the distillation column 2, the amount of the acid component mixed in the ester solvent increases, and the resulting ester solvent The purity may not be in the desired range. Further, excessively reducing the amount of the remaining low-boiling component is inefficient and disadvantageous for industrial production.

  When the residual alcohol is distilled and the concentration of the low boiling point component in the esterification reaction crude liquid is within the above range, the low boiling point component remaining in the esterification reaction crude liquid is concentrated at the top of the distillation column 2. The reflux ratio at this time is preferably 20 or more, more preferably 30 or more, and particularly preferably total reflux. In this state, a highly purified ester solvent is distilled from the side cut line H. In addition, the distribution ratio at the time of side cut distillation (column top reflux liquid amount: side cut liquid amount) is, for example, in the range of 10: 1 to 1: 5, preferably in the range of 5: 1 to 1: 3, particularly preferably. Is selected from the range of 3: 1 to 1: 2. When the distribution ratio is larger than 10: 1, the production efficiency is lowered, the amount of heating steam is large, and the cost is increased. When the distribution ratio is smaller than 1: 5, the quality (particularly acid content) of the product tends to be lowered. In addition, after obtaining a high purity ester solvent from the side cut line, the residue remaining in the distillation can 1 can be removed through the line I.

  Esterification reaction crude liquid obtained by esterifying reaction of alcohol and carboxylic acid in the presence of an acid catalyst in the presence of an acid catalyst was distilled without neutralization treatment. The ester solvent obtained by distilling and purifying using a column and distilling off low boiling components from the side cut line provided in the middle part of the distillation column has an alkali metal content of 2 wt. The alkali metal content can be reduced to 1 wt ppb or less by adjusting the temperature at the bottom of the column or the distribution ratio. In addition, the acid content is as extremely small as 0.01% by weight or less, which is the same level as when purified by a method including a neutralization step. In particular, when an ester solvent such as 1,3-diacetoxybutane having an atmospheric pressure boiling point of 220 to 250 ° C. is produced, the acid content of the ester solvent is 0.005% or less, cyclohexanol acetate, dipropylene When an ester solvent having a normal pressure boiling point of 220 ° C. or lower such as glycol methyl ether acetate or propylene glycol diacetate is produced, the acid content of the ester solvent is 0.001% by weight or lower. In addition, the manufacturing method of the ester solvent of this invention is especially suitable for manufacture of the thing whose boiling point of the ester solvent is higher than the boiling point of the alcohol which is a raw material, and the boiling point of carboxylic acid.

[Solvent composition for manufacturing electronic materials]

  An ester-based solvent produced according to the present invention, and a solvent composition for producing an electronic material according to the present invention comprising the same as a constituent component are a semiconductor resist, a color resist, an inkjet ink for a color filter, a resin composition for an overcoat, a photospacer. It is suitably used as a solvent for manufacturing electronic materials that require high quality, such as resist for resist and VA pattern, and is particularly suitable as a solvent for semiconductor resist that requires a metal component such as sodium to be controlled to a very small amount of 1 ppb or less. Preferably used. In addition, the solvent composition for electronic material manufacture of this invention may contain solvents other than the said ester solvent as needed.

EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited by these Examples.
In Examples 1 to 5 and Comparative Examples 1 to 10, the batch distillation apparatus shown in FIG. 1 was used to carry out dehydration esterification reaction and rectification. In addition, the theoretical plate number of the distillation column is 10, and the position of the side cut line is the theoretical plate from the low column to the 6th column.

Example 1
A distillation can was charged with 100 parts by weight of cyclohexanol, 66 parts by weight of acetic acid, 2 parts by weight of p-toluenesulfonic acid monohydrate, and 19 parts by weight of isobutyl acetate. The top pressure of the distillation tower is 40 kPa. The pressure was reduced to A to achieve total reflux. When water was generated in the distillate, the distillate was separated into liquids using a decanter. The organic layer was refluxed to the top of the tower, and the aqueous layer was extracted out of the system. When the generation of water was completed, the dehydration esterification reaction was completed, and a reaction crude liquid was obtained.
This reaction crude liquid was directly subjected to batch distillation using the apparatus shown in FIG. Isobutyl acetate and acetic acid were distilled off from the top of the column. At this time, the reflux ratio is 0.5, the upper limit of the distillation can is 150 ° C., and the pressure at the top of the column is 2.7 kPa. Reduced to A.
After the concentration of isobutyl acetate and acetic acid in the distillate decreased, the reflux ratio was set to 10 and cyclohexanol was removed. After removing cyclohexanol, the top of the column was brought to total reflux, and cyclohexanol acetate was distilled from the side cut line. At this time, the distribution ratio (top column reflux liquid amount: side cut liquid amount) was 3: 2.

(Example 2)
A distillation can was charged with 100 parts by weight of 1,3-butylene glycol, 147 parts by weight of acetic acid, 4 parts by weight of p-toluenesulfonic acid monohydrate, and 28 parts by weight of isobutyl acetate. The top pressure of the distillation tower is 40 kPa. The pressure was reduced to A to achieve total reflux. When water was generated in the distillate, the distillate was separated into liquids using a decanter. The organic layer was refluxed to the top of the tower, and the aqueous layer was extracted out of the system. At the end of water generation, the dehydration esterification reaction was completed, and a reaction crude liquid was obtained.
This reaction crude liquid was directly subjected to batch distillation using the apparatus shown in FIG. Isobutyl acetate and acetic acid were separated by distillation from the top of the column. At this time, the reflux ratio is 0.5, the upper limit of the distillation can temperature is 150 ° C., and the pressure at the top of the column is 2.7 kPa. Reduced to A.
After the isobutyl acetate and acetic acid concentrations in the distillate decreased, the reflux ratio was set to 10 to remove 1,3-butylene glycol and 1,3-butylene glycol monoacetate. After removing 1,3-butylene glycol and 1,3-butylene glycol monoacetate, the top of the column was brought to total reflux, and 1,3-diacetoxybutane was distilled from the side cut line. At this time, the distribution ratio (top column reflux liquid amount: side cut liquid amount) was 3: 2.

Example 3
100 parts by weight of dipropylene glycol monomethyl ether, 45 parts by weight of acetic acid, p- monohydrate 1 parts by weight of toluene sulfonic acid were charged isobutyl acetate 16 parts by weight distilled can. The top pressure of the distillation tower is 40 kPa. The pressure was reduced to A to achieve total reflux. When water was generated in the distillate, the distillate was separated into liquids using a decanter. The organic layer was refluxed to the top of the tower, and the aqueous layer was extracted out of the system. At the end of water generation, the dehydration esterification reaction was completed, and a crude reaction liquid was obtained.
This reaction crude liquid was directly subjected to batch distillation using the apparatus shown in FIG. Isobutyl acetate and acetic acid were distilled off from the top of the column. At this time, the reflux ratio is 0.5, the upper limit of the distillation can is 150 ° C., and the pressure at the top of the column is 2.7 kPa. Reduced to A.
The reflux ratio from the isobutyl acetate and acetic acid concentration in the distillate was reduced to 10 to remove the dipropylene glycol monomethyl ether. After removal of the dipropylene glycol monomethyl ether, the top of the column and total reflux to distill dipropylene glycol methyl ether acetate from the liquid phase side cut line. At this time, the distribution ratio (top column reflux liquid amount: side cut liquid amount) was 3: 2.

(Example 4)
A distillation can was charged with 100 parts by weight of propylene glycol, 174 parts by weight of acetic acid, 5 parts by weight of p-toluenesulfonic acid monohydrate, and 31 parts by weight of isobutyl acetate. The top pressure of the distillation tower is 40 kPa. The pressure was reduced to A to achieve total reflux. When water was generated in the distillate, the distillate was separated into liquids using a decanter. The organic layer was refluxed to the top of the tower, and the aqueous layer was extracted out of the system. At the end of water generation, the dehydration esterification reaction was completed, and a crude reaction liquid was obtained.
This reaction crude liquid was directly subjected to batch distillation using the apparatus shown in FIG. Isobutyl acetate and acetic acid were distilled off from the top of the column. At this time, the reflux ratio is 0.5, the upper limit of the distillation can is 150 ° C., and the pressure at the top of the column is 2.7 kPa. Reduced to A.
After the concentration of isobutyl acetate and acetic acid in the distillate decreased, the reflux ratio was set to 10 to remove propylene glycol and propylene glycol monoacetate. After removing propylene glycol and propylene glycol monoacetate, the top of the column was brought to total reflux, and propylene glycol diacetate was distilled from the side cut line. At this time, the distribution ratio (top column reflux liquid amount: side cut liquid amount) was 3: 2.

(Example 5)
A distillation can was charged with 100 parts by weight of 1,6-hexanediol, 112 parts by weight of acetic acid, 3 parts by weight of p-toluenesulfonic acid monohydrate and 24 parts by weight of isobutyl acetate. The top pressure of the distillation tower is 40 kPa. The pressure was reduced to A to achieve total reflux. When water was generated in the distillate, the distillate was separated into liquids using a decanter. The organic layer was refluxed to the top of the tower, and the aqueous layer was extracted out of the system. When the generation of water was completed, the dehydration esterification reaction was completed, and a reaction crude liquid was obtained.
This reaction crude liquid was directly subjected to batch distillation using the apparatus shown in FIG. Isobutyl acetate and acetic acid were distilled off from the top of the column. At this time, the reflux ratio is 0.5, the upper limit of the distillation can temperature is 165 ° C., and the pressure at the top of the column is 2.7 kPa. Reduced to A.
After the concentration of isobutyl acetate and acetic acid in the distillate decreased, the reflux ratio was set to 10 and 1,6-hexanediol and 1,6-hexanediol monoacetate were removed. After removal of 1,6-hexanediol and 1,6-hexanediol mono acetate, the top of the column and total reflux, 1 from the liquid phase side cut line 6 - was distilled off diacetoxy hexane. At this time, the distribution ratio (top column reflux liquid amount: side cut liquid amount) was 3: 2.

(Comparative Example 1)
The reaction crude liquid synthesized in the same manner as in Example 1 was transferred to a stirring tank provided separately from the batch distillation apparatus shown in FIG. 1, and 0.6 parts by weight of caustic soda flakes was added. Stir for 5 hours to neutralize the acid catalyst.
The reaction crude liquid after completion of neutralization was transferred again to the batch distillation apparatus of FIG. 1 and batch distillation was performed. The top pressure of the distillation tower is 40 kPa. The pressure was reduced to A to achieve total reflux. After the column was stabilized at the total reflux state, the reflux ratio was changed, and isobutyl acetate and acetic acid were separated by distillation from the top of the column. At this time, the reflux ratio is 0.5, the upper limit of the distillation can is 150 ° C., and the pressure at the top of the column is 2.7 kPa. Reduced to A.
After the concentration of isobutyl acetate and acetic acid in the distillate decreased, the reflux ratio was set to 10 and cyclohexanol was removed. After removing cyclohexanol, the reflux ratio was set to 0.5, and cyclohexanol acetate was distilled from the top of the column.

(Comparative Example 2)
The reaction crude liquid synthesized in the same manner as in Example 2 was transferred to a stirring tank provided separately from the batch distillation apparatus shown in FIG. 1, and 1.3 parts by weight of caustic soda flakes were added. Stir for 5 hours to neutralize the acid catalyst.
The reaction crude liquid after completion of neutralization was transferred again to the batch distillation apparatus of FIG. 1 and batch distillation was performed. The top pressure of the distillation tower is 40 kPa. The pressure was reduced to A to achieve total reflux. After the column was stabilized at the total reflux state, the reflux ratio was changed, and isobutyl acetate and acetic acid were separated by distillation from the top of the column. At this time, the reflux ratio is 0.5, the upper limit of the distillation can is 150 ° C., and the pressure at the top of the column is 2.7 kPa. Reduced to A.
After the concentration of isobutyl acetate and acetic acid in the distillate decreased, the reflux ratio was set to 10 to remove 1,3-butylene glycol and 1,3-butylene glycol monoacetate. After removal of 1,3-butylene glycol and 1,3-butylene glycol monoacetate, the reflux ratio was set to 0.5, and 1,3-diacetoxybutane was distilled from the top of the column.

(Comparative Example 3)
The reaction crude liquid synthesized in the same manner as in Example 3 was transferred to a stirring tank provided separately from the batch distillation apparatus shown in FIG. 1, and 0.4 part by weight of caustic soda flakes was added. Stir for 5 hours to neutralize the acid catalyst.
The reaction crude liquid after completion of neutralization was transferred again to the batch distillation apparatus of FIG. 1 and batch distillation was performed. The top pressure of the distillation tower is 40 kPa. The pressure was reduced to A to achieve total reflux. After the column was stabilized at the total reflux state, the reflux ratio was changed, and isobutyl acetate and acetic acid were separated by distillation from the top of the column. At this time, the reflux ratio is 0.5, the upper limit of the distillation can is 150 ° C., and the pressure at the top of the column is 2.7 kPa. Reduced to A.
The reflux ratio from the isobutyl acetate and acetic acid concentration in the distillate was reduced to 10 to remove the dipropylene glycol monomethyl ether. After removal of the dipropylene glycol monomethyl ether, the reflux ratio was 0.5, it was distilled dipropylene glycol methyl ether acetate from the top of the tower.

(Comparative Example 4)
The reaction crude liquid synthesized in the same manner as in Example 4 was transferred to a stirring tank provided separately from the batch distillation apparatus shown in FIG. 1, and 1.6 parts by weight of caustic soda flakes were added. Stir for 5 hours to neutralize the acid catalyst.
The reaction crude liquid after completion of neutralization was transferred again to the batch distillation apparatus of FIG. 1 and batch distillation was performed. The top pressure of the distillation tower is 40 kPa. The pressure was reduced to A to achieve total reflux. After the column was stabilized at the total reflux state, the reflux ratio was changed, and isobutyl acetate and acetic acid were separated by distillation from the top of the column. At this time, the reflux ratio is 0.5, the upper limit of the distillation can is 150 ° C., and the pressure at the top of the column is 2.7 kPa. Reduced to A.
After the concentration of isobutyl acetate and acetic acid in the distillate decreased, the reflux ratio was set to 10 to remove propylene glycol and propylene glycol monoacetate. After removing propylene glycol and propylene glycol monoacetate, the reflux ratio was set to 0.5, and propylene glycol diacetate was distilled from the top of the column.

(Comparative Example 5)
The reaction crude liquid synthesized in the same manner as in Example 5 was transferred to a stirring tank provided separately from the batch distillation apparatus shown in FIG. 1, and 1 part by weight of caustic soda flakes was added. Stir for 5 hours to neutralize the acid catalyst.
The reaction crude liquid after completion of neutralization was transferred again to the batch distillation apparatus of FIG. 1 and batch distillation was performed. The top pressure of the distillation tower is 40 kPa. The pressure was reduced to A to achieve total reflux. After the column was stabilized at the total reflux state, the reflux ratio was changed, and isobutyl acetate and acetic acid were separated by distillation from the top of the column. At this time, the reflux ratio is 0.5, the upper limit of the distillation can temperature is 165 ° C., and the pressure at the top of the column is 2.7 kPa. Reduced to A.
After the concentration of isobutyl acetate and acetic acid in the distillate decreased, the reflux ratio was set to 10 and 1,6-hexanediol and 1,6-hexanediol monoacetate were removed. After removal of 1,6-hexanediol and 1,6-hexanediol mono acetate, a reflux ratio of 0.5, 1 from the top, 6 - it was distilled off diacetoxy hexane.

(Comparative Example 6)
The reaction crude liquid synthesized in the same manner as in Example 1 was directly subjected to batch distillation using the apparatus shown in FIG. Isobutyl acetate and acetic acid were separated by distillation from the top of the column. At this time, the reflux ratio is 0.5, the upper limit of the distillation can is 150 ° C., and the pressure at the top of the column is 2.7 kPa. Reduced to A.
After the concentration of isobutyl acetate and acetic acid in the distillate decreased, the reflux ratio was set to 10 and cyclohexanol was removed. After removing cyclohexanol, the reflux ratio was set to 0.5, and cyclohexanol acetate was distilled from the top of the column.

(Comparative Example 7)
The reaction crude liquid synthesized in the same manner as in Example 2 was directly subjected to batch distillation using the apparatus shown in FIG. Isobutyl acetate and acetic acid were separated by distillation from the top of the column. At this time, the reflux ratio is 0.5, the upper limit of the distillation can is 150 ° C., and the pressure at the top of the column is 2.7 kPa. Reduced to A.
After the concentration of isobutyl acetate and acetic acid in the distillate decreased, the reflux ratio was set to 10 to remove 1,3-butylene glycol and 1,3-butylene glycol monoacetate. After removal of 1,3-butylene glycol and 1,3-butylene glycol monoacetate, the reflux ratio was set to 0.5, and 1,3-diacetoxybutane was distilled from the top of the column.

(Comparative Example 8)
The reaction crude liquid synthesized in the same manner as in Example 3 was directly subjected to batch distillation using the apparatus shown in FIG. Isobutyl acetate and acetic acid were separated by distillation from the top of the column. At this time, the reflux ratio is 0.5, the upper limit of the distillation can is 150 ° C., and the pressure at the top of the column is 2.7 kPa. Reduced to A.
The reflux ratio from the isobutyl acetate and acetic acid concentration in the distillate was reduced to 10 to remove the dipropylene glycol monomethyl ether. After removal of the dipropylene glycol monomethyl ether, the reflux ratio was 0.5, it was distilled dipropylene glycol methyl ether acetate from the top of the tower.

(Comparative Example 9)
The reaction crude liquid synthesized in the same manner as in Example 4 was directly subjected to batch distillation using the apparatus shown in FIG. Isobutyl acetate and acetic acid were separated by distillation from the top of the column. At this time, the reflux ratio is 0.5, the upper limit of the distillation can is 150 ° C., and the pressure at the top of the column is 2.7 kPa. Reduced to A.
After the concentration of isobutyl acetate and acetic acid in the distillate decreased, the reflux ratio was set to 10 to remove propylene glycol and propylene glycol monoacetate. After removing propylene glycol and propylene glycol monoacetate, the reflux ratio was set to 0.5, and propylene glycol diacetate was distilled from the top of the column.

(Comparative Example 10)
The reaction crude liquid synthesized in the same manner as in Example 5 was directly subjected to batch distillation using the apparatus shown in FIG. Isobutyl acetate and acetic acid were separated by distillation from the top of the column. At this time, the reflux ratio is 0.5, the upper limit of the distillation can temperature is 165 ° C., and the pressure at the top of the column is 2.7 kPa. Reduced to A.
After the concentration of isobutyl acetate and acetic acid in the distillate decreased, the reflux ratio was set to 10 and 1,6-hexanediol and 1,6-hexanediol monoacetate were removed. After removing 1,6-hexanediol and 1,6-hexanediol monoacetate, the reflux ratio was set to 0.5, and 1,6-diacetoxyhexane was distilled from the top of the column.

  The Na content and acid content of the products (ester solvents) obtained in Examples and Comparative Examples were measured by the following methods. The results are shown in Table 1.

(Na content measuring method)
Measurement was carried out by standard addition method using ICP-MS (Agilent HP-7500 type).
As the standard mixed solution, XSTC-22 100 ppm (containing 23 elements) manufactured by SPEX was diluted 100-fold with isopropyl alcohol (for Wako Pure Chemical Industries Electronic Materials).
(Acid content measurement method)
The measurement was performed according to JIS K1514 3.10.

As the measurement results in Table 1 show, all of the ester solvents obtained in Examples 1 to 5 were subjected to distillation purification without neutralization, and after distilling off low-boiling components, Since it is distilled from the side cut line provided in the middle part, both the Na content and the acid content are extremely low. On the other hand, since the ester solvents obtained in Comparative Examples 1 to 5 are neutralized, the residual Na content is high and the ester solvent is distilled from the top of the distillation column. In Comparative Examples 6 to 10, the acid content is high.

It is the schematic which shows an example of the apparatus (batch type distillation apparatus) which can be used for implementation of the manufacturing method of the ester solvent of this invention.

Explanation of symbols

1: Distillation can capable of reacting alcohol and acid inside 2: Distillation column 3: Vacuum unit 4: Decanter 4-1: Aqueous layer in decanter 4-2: Organic layer in decanter 5: Pump 6: Heat exchanger 7: Heat exchanger A to I: Line

Claims (5)

A crude esterification reaction liquid obtained by esterifying an alcohol and a carboxylic acid in the presence of at least one acid catalyst selected from mineral acid, p-toluenesulfonic acid, and boron trifluoride (BF ₃ ) A method for producing an ester-based solvent that is purified by distillation using a distillation column, which is obtained by performing an esterification reaction in the distillation can using a batch distillation apparatus in which the distillation can is connected to the bottom of the distillation tower. The resulting reaction crude liquid is subjected to distillation purification without neutralization treatment, and after distilling off low-boiling components, an ester solvent is distilled off from a side cut line provided in the middle part of the distillation column. Solvent manufacturing method.   The method for producing an ester solvent according to claim 1, wherein the ester solvent has a boiling point of 120 to 300 ° C at normal pressure.   3. The alcohol according to claim 1, wherein the alcohol is one alcohol selected from cyclohexanol, 1,3-butylene glycol, dipropylene glycol monomethyl ether, propylene glycol, and 1,6-hexanediol, and the carboxylic acid is acetic acid. A method for producing an ester solvent. A distillation can capable of reacting alcohol and carboxylic acid inside, a distillation column whose bottom is connected to the distillation can, a side cut line provided in the middle of the distillation column, and connected to the top of the distillation column In the facility having the decanter and the vacuum unit capable of adjusting the pressure at the top of the distillation column, the water layer and the organic layer are separated by a decanter connected to the top of the distillation column at the time of the reaction between the alcohol and the carboxylic acid, The aqueous layer is removed from the system and the organic layer is refluxed to the top of the distillation column while the esterification reaction proceeds, and the low-boiling components are removed from the top of the distillation column during purification of the resulting esterification crude liquid by distillation. Then, the ester-based solvent according to any one of claims 1 to 3 , wherein the ester-based solvent is distilled from the distillation column side cut line in a state where the low-boiling component remaining at the top of the column is concentrated by refluxing. Made Method. Vapor sodium content than sidecut lines provided in the middle portion of the column is distilled off the ester solvent is less than 2 wt ppb, a method of manufacturing an ester solvent according to any one of claims 1 to 4 .

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