JPH09221531A - Production of aromatic carboxylic ester of novolak phenol resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an arom. carboxylic ester of a novolak phenol resin at a high degree of esterification in a high yield by reacting a novolak phenol resin with an arom. carboxylic acid in the presence of a specific catalyst under specified conditions. SOLUTION: This ester is produced by reacting a novolak phenol resin with an arom. carboxylic acid in the presence of an org. sulfonic acid catalyst. pref. p-toluenesulfonic acid or benzenesulfonic acid. Pref. the reaction is conducted by using the acid, i.e., one of the reactants, as the solvent.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an aromatic carboxylic acid ester of a novolac type phenolic resin. More specifically, the present invention relates to a method for producing an aromatic carboxylic acid ester of a novolak type phenol resin using an organic sulfonic acid catalyst. The curable composition of the ester and the epoxy resin obtained by the method of the present invention is a paint,
Suitable for adhesives, printed circuit boards, sealants for semiconductor devices, coating materials, molding materials, etc.

[0002]

BACKGROUND OF THE INVENTION No useful process has been established so far for the esterification of phenol novolaks with aromatic carboxylic acids. Generally, it is difficult to directly produce an aromatic carboxylic acid ester from a phenol derivative and an aromatic carboxylic acid in terms of reaction equilibrium. Therefore, the aromatic carboxylic acid ester of the phenol novolac is generally known as a corresponding aromatic carboxylic acid ester. Manufactured from acid chloride and phenol novolac. However, this method is not satisfactory as an industrial method for producing an aromatic carboxylic acid ester of phenol novolac, such as using an expensive aromatic carboxylic acid chloride and generating hydrogen chloride.
As another method, esterification is carried out using a dehydration condensing agent such as N, N'-dicyclohexylcarbodiimide (DCC), but by-products are formed or the urea derivative is removed after the reaction. However, the DCC is expensive and the DCC is expensive.

The esterification reaction of an aliphatic alcohol with a carboxylic acid is carried out by using a mineral acid such as sulfuric acid. In the case of esterification of a phenol derivative, a sulfuric acid catalyst is generally used as a side reaction. It is known that the sulfonation reaction of a benzene ring having a phenolic hydroxyl group proceeds very easily. Moreover, JP-A-7-29
According to 1898, esterification under this acid condition is also said to be difficult because side reactions such as replacement of phenolic hydroxyl groups with sulfone groups occur. Tetrahedron Letters (Te
trahedron Letters) Volume 37, 34
Page 53 (1971) shows that phenol derivatives and carboxylic acids, toluene in the presence of a catalyst consisting of boric acid and sulfuric acid,
It has been shown that the corresponding ester is produced using xylene, sulfolane, etc. as a solvent.

[0004]

In the case of esterification of phenol novolac with an aromatic carboxylic acid, according to the follow-up test by the present inventors, even if a catalyst consisting of sulfuric acid alone or a mixture of sulfuric acid and boric acid is used, for example, The reaction does not proceed at all under low temperature and mild conditions such as under toluene reflux, which is the condition described in the literature, and under the reflux of xylene or mesitylene, which is a higher temperature, the side reaction of sulfonation with sulfuric acid is mainly,
It turned out that the selectivity of the target substance was extremely low and not practical. That is, in the esterification of phenol novolac with an aromatic carboxylic acid using sulfuric acid as a catalyst, there is a problem that the reaction does not proceed at low temperature and side reactions such as sulfonation occur preferentially at high temperature. An object of the present invention is to avoid the above problems in the esterification of a novolac type phenolic resin and an aromatic carboxylic acid, and to perform the esterification of a novolac type phenolic resin and an aromatic carboxylic acid with high selectivity, and at a low cost. It is an object of the present invention to provide a method for industrially producing an aromatic carboxylic acid ester of a novolak type phenolic resin, which can be easily post-treated.

[0005]

Means for Solving the Problems The inventors of the present invention have diligently studied esterification of a novolac type phenolic resin and an aromatic carboxylic acid in order to solve the above problems. As a result, surprisingly, sulfuric acid was not used as an acid catalyst. By using an organic sulfonic acid such as p-toluene sulfonic acid or benzene sulfonic acid and reacting under specific conditions, the side reaction between the novolac type phenol resin and the acid catalyst, which is the side reaction mentioned above, is almost eliminated. No progress, the esterification reaction of the novolak type phenolic resin and the aromatic carboxylic acid proceeds preferentially, and the aromatic carboxylic acid ester of the novolak type phenolic resin can be obtained in high yield and high esterification rate. And completed the present invention. That is, the present invention is a method for producing an aromatic carboxylic acid ester of a novolac type phenol resin, which comprises reacting a novolac type phenol resin with an aromatic carboxylic acid in the presence of an organic sulfonic acid catalyst. Hereinafter, the method of the present invention will be described in detail.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(Novolak type phenolic resin) The novolak type phenolic resin used in the present invention includes phenols such as phenol or cresol and aldehydes such as formaldehyde, paraformaldehyde, polyoxymethylene, trioxane, acetaldehyde, benzaldehyde and the like, hydrochloric acid, sulfuric acid and sulfamine. An acid, a product obtained by reacting in the presence of an acid catalyst such as p-toluenesulfonic acid,
Among them, phenol novolac obtained by reacting phenol with formaldehyde is preferable. The molecular weight of phenol novolac is about 200-1000. Further, as a commercially available phenol novolac used in the present invention, for example, PSM-4327 (softening point 9 by Gunei Chemical Co., Ltd.)
5 ° C, viscosity / 150 ° C 7.0 ps, active group equivalent 103
g / equivalent, number average degree of polymerization 4). In the following embodiments, phenol novolac will be described as an example.

(Aromatic Carboxylic Acid) As the aromatic carboxylic acid, for example, benzoic acid, toluic acid, monoalkylbenzoic acid such as ethylbenzoic acid, and monoalkoxybenzoic acid such as methoxybenzoic acid can be used. ,
Benzoic acid is preferred because of its use as a curable composition. The amount of phenol novolac charged with respect to the aromatic carboxylic acid can be arbitrarily set as long as the number of moles of the phenolic hydroxyl group is equal to or less than the equimolar amount of the aromatic carboxylic acid, but usually 5 to 50 mol%, preferably 10 ~ 30 mol%
It is. If the concentration is lower than this, the production efficiency is poor and industrially unsuitable. If the concentration is higher than this, the esterification rate per hour is lowered and the reaction takes a long time.

(Organic Sulfonic Acid) The catalyst used in the present invention is an organic sulfonic acid. Specific examples of the organic sulfonic acid include, for example, methanesulfonic acid, trifluoromethanesulfonic acid, laurylsulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, 1-naphthalenesulfonic acid, 2-naphthalenesulfonic acid and the like. Is mentioned. Among these, p-toluenesulfonic acid and benzenesulfonic acid are preferable. The amount of the catalyst used in the present invention is usually 0.01 to 3 mol%, preferably 0.2 to 1 mol% based on the aromatic carboxylic acid. If the concentration is lower than this, the reaction rate will decrease, and if the concentration is higher, by-products will increase.

As the solvent for the (solvent) esterification, an aromatic carboxylic acid which is a reaction substrate is used, but a general solvent may be mixed, for example, an aromatic solvent such as benzene, toluene, xylene and mesitylene, Examples thereof include ether solvents such as tetrahydrofuran, dioxane and diethylene glycol dimethyl ether, aprotic polar solvents such as N, N′-dimethylformamide and dimethyl sulfoxide, and ketone solvents such as methyl isobutyl ketone. Moreover, you may combine them arbitrarily. Although the amount of the solvent can be arbitrarily set, the phenol novolac concentration is usually 1 to 50% by weight, preferably 10 to 30% by weight from the viewpoint of an industrial method.

(Reaction Method) The reaction temperature in the present invention is usually 150 to 200 ° C. At higher temperatures, the selectivity decreases due to the decomposition of phenol novolac, and at lower temperatures, the reaction proceeds very slowly. The reaction time can be set arbitrarily, but it is usually in the range of 1 to 20 hours. It is possible to achieve a predetermined esterification rate by allowing the reaction to proceed for a long time. The reaction is usually carried out at normal pressure, but it can also be carried out under pressure or under reduced pressure. Further, in order to remove water for favoring the equilibrium of the reaction, it may be azeotroped with toluene, xylene or the like, or it may be removed from the system by entraining water while blowing an inert gas such as nitrogen. Is also preferable. Setting the reaction atmosphere under an inert gas such as nitrogen or argon also has an effect of preventing side reactions such as oxidation. After the reaction,
The aromatic carboxylic acid ester of phenol novolac can be obtained by removing the solvent and the aromatic carboxylic acid from the reaction mixture by neutralization or distillation and extracting with a solvent such as methyl isobutyl ketone. At this time, the aromatic carboxylic acid recovered by distillation can be reused in the reaction. Furthermore, by extracting with hot toluene, a higher purity aromatic carboxylic acid ester of phenol novolac can be obtained.

[0011]

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the examples as long as the gist thereof is not exceeded. The product is
Using high performance liquid chromatography, the conversion of phenol novolac was determined by the following formula by the absolute calibration method. Further, the aromatic carboxylic acid ester of phenol novolac and other by-products produced in the reaction were also determined by the absolute calibration method in the same manner. The esterification ratio was determined by the following formula by titrating the residual phenolic hydroxyl group. As shown in the following formula, the conversion rate of phenol novolac represents the consumption amount of phenol novolac, and the esterification rate represents the rate of esterification of the phenolic hydroxyl group, which are numerical values having different meanings.

[0012]

[Equation 1]

[0013]

[Equation 2]

Example 1 A four-necked flask having an internal volume of 100 ml equipped with a mechanical stirrer, a thermometer, a blowing tube, and a Dean-Stark trap was placed in a phenol novolak (P manufactured by Gunei Chemical Co., Ltd.).
SM-4327, softening point 95 ° C, viscosity / 150 ° C 7.
0 ps, active group equivalent 103 g / equivalent, number average degree of polymerization 4)
7.2 g (70 mmol: number of phenolic hydroxyl groups), 61.0 g (500 mmol) of benzoic acid, 0.76 g (4 mmol) of p-toluenesulfonic acid (monohydrate) were added, and 180 ° C. in an oil bath. The mixture was stirred for 6 hours while blowing nitrogen gas. After completion of the reaction, benzoic acid was removed from the reaction mixture, organic matter was extracted with methyl isobutyl ketone, and dried under reduced pressure at 100 ° C./1 mmHg for 2 hours to obtain the objective benzoic acid ester of phenol novolac (10.3 g ). When the reaction mixture was analyzed, the conversion rate of phenol novolac was 100%, and the benzoic acid ester of the objective phenol novolac was 6%.
2%, purity 95%, and the remaining 5% was a sulfonated product formed by a side reaction. By adding hot toluene to this compound and filtering it, a higher purity of 1
00% of the desired product was obtained (9.6 g). This compound had the following physicochemical properties and was confirmed to be a benzoic acid ester of phenol novolac. IR (KBr method, cm ^-1 ): 1735, 1600, 71
0

Example 2 The reaction conditions were the same as in Example 1, but the reaction temperature was 150.
The reaction was carried out by changing the temperature to ° C. After the reaction was completed, the reaction mixture was analyzed and the conversion of phenol novolac was 22.
%, The objective benzoic acid ester of phenol novolac has an esterification rate of 9% and a purity of 97%.
% Was a sulfonated product formed by a side reaction.

Example 3 The reaction was carried out by changing the acid catalyst to benzenesulfonic acid (monohydrate) while maintaining the reaction conditions of Example 1 as they were. After completion of the reaction, the reaction mixture was analyzed and the conversion of phenol novolac was 100%, the objective benzoic acid ester of phenol novolac had an esterification rate of 60% and a purity of 95%, and the remaining 5% was a side reaction. It was a sulfonated product produced by.

Example 4 p-Methoxybenzoic acid was used as the aromatic carboxylic acid, and the reaction temperature was 190 ° C., with the reaction conditions of Example 1 unchanged.
Was changed to the reaction. After the reaction was completed, the reaction mixture was analyzed and the conversion of phenol novolac was 100.
%, The target p-methoxybenzoic acid ester of phenol novolac had an esterification rate of 65% and a purity of 93%, and the remaining 7% was a sulfonated product formed by a side reaction.

Example 5 Using the same reaction conditions as in Example 1, p-methylbenzoic acid was used as the aromatic carboxylic acid, and the reaction temperature was changed to 190 ° C. to carry out the reaction. After the reaction was completed, the reaction mixture was analyzed and the conversion of phenol novolac was 100%.
The target product, p-methylbenzoic acid ester of phenol novolac, has an esterification rate of 67% and a purity of 93%.
The remaining 7% was a sulfonated product formed by a side reaction.

Example 6 With the reaction conditions of Example 1 unchanged, only the amount of acid catalyst was 0.
The reaction was performed by changing to 19 g (1 mmol). After completion of the reaction, the reaction mixture was analyzed to find that the conversion rate of phenol novolac was 100%, and the objective benzoic acid ester of phenol novolac was 26% esterification rate and 9% purity.
8%, and the remaining 2% was a sulfonated product formed by a side reaction.

Example 7 With the reaction conditions of Example 1 unchanged, nitrogen blowing was stopped and the reaction was carried out under a reduced pressure of 350 mmHg for 3 hours. After completion of the reaction, the reaction mixture was analyzed to find that the conversion rate of phenol novolac was 100% and that the target benzoic acid ester of phenol novolac was 100% esterification rate.
%, The purity was 96%, and the remaining 4% was a sulfonated product formed by a side reaction.

Comparative Example 1 The reaction was carried out by changing the acid catalyst to sulfuric acid with the reaction conditions of Example 1 unchanged. After completion of the reaction, the reaction mixture was analyzed to find that the conversion of phenol novolac was 100%, the objective benzoic acid ester of phenol novolac had an esterification rate of 70% and a purity of 45%, and the remaining 55%.
Was a sulfonated product formed by a side reaction.

Comparative Example 2 The reaction was carried out by changing the acid catalyst to sulfuric acid while keeping the reaction conditions of Example 2 unchanged. After the completion of the reaction, the reaction mixture was analyzed to find that the conversion of phenol novolac was 100%, the objective benzoic acid ester of phenol novolac had an esterification rate of 14%, a purity of 53%, and the remaining 47%.
Was a sulfonated product formed by a side reaction.

[0023]

EFFECTS OF THE INVENTION According to the present invention, a novolak type phenol resin and an aromatic carboxylic acid can be esterified with high selectivity, and the ester produced by distillation and extraction can be easily separated from the reaction mixture. You can

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location // C07B 61/00 300 C07B 61/00 300

Claims (6)

[Claims] 1. A method for producing an aromatic carboxylic acid ester of a novolak type phenol resin, which comprises reacting a novolak type phenol resin with an aromatic carboxylic acid in the presence of an organic sulfonic acid catalyst. 2. The method for producing an aromatic carboxylic acid ester of a novolac type phenolic resin according to claim 1, wherein p-toluenesulfonic acid or benzenesulfonic acid is used as the catalyst. 3. The method for producing an aromatic carboxylic acid ester of a novolac type phenol resin according to claim 1, wherein an aromatic carboxylic acid which is a reaction substrate is used as a solvent. 4. The method for producing an aromatic carboxylic acid ester of a novolac type phenol resin according to claim 1, wherein phenol novolac is used as the novolac type phenol resin. 5. The method for producing an aromatic carboxylic acid ester of a novolac type phenolic resin according to claim 1, wherein benzoic acid is used as the aromatic carboxylic acid. 6. The reaction according to claim 1, which is carried out at 150 to 200 ° C.
6. A method for producing an aromatic carboxylic acid ester of a novolac type phenolic resin according to any one of items 1 to 5.