Method for producing (meth)acrylic acid esters

Abstract

To provide a method for producing a (meth)acrylic acid ester having a lactone structure with a low boron content.SOLUTION: There is provided a method for producing a (meth)acrylic acid ester which comprises: a step of reducing a cyclic acid anhydride of the formula (2) with a boron based reducing agent to obtain a lactone compound of the formula (3); a step of adding formic acid to the lactone compound to obtain a formic acid ester of the formula (4); a step of purifying the formic acid ester by thin-film distillation; and a step of obtaining a (meth)acrylic acid ester of the formula (1) from the purified formic acid ester. Wherein, X represents a methylene group or an ethylene group and R represents H or a methyl group.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to a method for producing (meth)acrylic acid esters. [Background technology]

[0002] (Meth)acrylic acid esters with a lactone structure are useful as raw materials for electronic materials. Patent Document 1 describes a method for producing a (meth)acrylic acid ester having a lactone structure via a reaction step using a boron-based reducing agent. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2002-234882 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] (Meth)acrylic acid esters produced via a reaction process using a boron-based reducing agent have a high boron content. In recent years, there has been a demand for lower metal content in the raw materials of electronic materials. In particular, metals in semiconductor materials significantly affect semiconductor performance, so their content must be kept as low as possible. Boron is sometimes included in this category.

[0005] The present invention aims to provide a method for producing (meth)acrylic acid esters having a lactone structure and a low boron content. [Means for solving the problem]

[0006] The present invention is as follows: A step of reducing a cyclic acid anhydride represented by the following formula (2) with a boron-based reducing agent to obtain a lactone compound represented by the following formula (3), A step of adding formic acid to the lactone compound to obtain a formic acid ester represented by the following formula (4): A step of purifying the formic acid ester by thin-film distillation, and A method for producing a (meth)acrylic acid ester, comprising the step of obtaining a (meth)acrylic acid ester represented by the following formula (1) from the purified formic acid ester.

[0007] [ka] However, X represents a methylene group or an ethylene group, and R represents a hydrogen atom or a methyl group. [Effects of the Invention]

[0008] According to the present invention, (meth)acrylic acid esters having a lactone structure and low boron content can be produced. [Modes for carrying out the invention]

[0009] In this invention, "(meth)acrylic acid ester" means acrylic acid ester or methacrylic acid ester. "(meth)acryloyloxy group" means acryloyloxy group or methacryloyloxy group. The "~" symbol indicating a numerical range means that the numbers before and after it are included as the lower and upper limits, respectively.

[0010] The present invention provides a method for producing (meth)acrylic acid esters (hereinafter also referred to as "this production method"), which comprises the following steps A to D. Step A: A step of reducing a cyclic acid anhydride represented by the following formula (2) with a boron-based reducing agent to obtain a lactone compound represented by the following formula (3). Step B: A step in which formic acid is added to the lactone compound obtained in Step A to obtain a formic acid ester represented by the following formula (4). Step C: A step in which the formic acid ester obtained in Step B is purified by thin-film distillation. Step D: A step to obtain (meth)acrylic acid ester represented by the following formula (1) from the formic acid ester purified in Step C. The lactone compound is a solid at room temperature (e.g., 20 °C), and the formate ester is a liquid at room temperature.

[0011]

Chemical formula

[0012] <Process A> In Process A, for example, a boron-based reducing agent is added to a solution containing a cyclic anhydride and a solvent and reacted. After the reaction, water is added to the obtained reaction solution as necessary, and then an acid is added for neutralization, and preferably an acid is further added to make it acidic. When a boron-based reducing agent acts on a cyclic anhydride, the anhydride structure is converted into a boron complex of a hydroxycarboxylic acid. Then, by adding an acid to make the reaction solution neutral to acidic, the boron complex of the hydroxycarboxylic acid undergoes lactonization.

[0013] As the starting material cyclic anhydride, commercially available ones may be used, or those produced by known production methods may be used. Examples of the production method of the cyclic anhydride include the method described in JP-A-2002-234882.

[0014] Examples of the boron-based reducing agent include borane dimethyl sulfide, sodium borohydride, lithium borohydride, potassium borohydride, zinc borohydride, lithium tri-s-butylborohydride, potassium tri-s-butylborohydride, lithium triethylborohydride, etc. These boron-based reducing agents may be used alone or in combination of two or more. As the boron-based reducing agent, sodium borohydride is preferred because it is easy to obtain and handle, and the reaction conditions are mild.

[0015] The amount of boron-based reducing agent used is preferably 0.5 to 1.5 times the molar amount relative to the cyclic acid anhydride. If the amount of boron-based reducing agent is above the lower limit, the reaction proceeds easily, and if it is below the upper limit, the reaction can be prevented from proceeding excessively and being reduced to a diol. Therefore, if the amount of boron-based reducing agent used is within the above range, the yield of the lactone compound is excellent.

[0016] Examples of solvents include alcoholic solvents such as methanol and ethanol; etheric solvents such as tetrahydrofuran, dimethoxyethane, diglyme, and trigrime; esteric solvents such as ethyl acetate and γ-butyrolactone; nitrile solvents such as acetonitrile; amide solvents such as N,N-dimethylformamide (DMF), N,N-dimethylacetamide, and N-methylpyrrolidone; hydrocarbon solvents such as toluene and hexane; and dimethyl sulfoxide. These solvents may be used individually or in combination of two or more. Digrime, N,N-dimethylformamide (DMF), N,N-dimethylacetamide, and N-methylpyrrolidone are preferred as solvents due to their high reaction rate, high solubility of boron-based reducing agents and cyclic acid anhydrides, and excellent safety.

[0017] From the viewpoint of obtaining a sufficient reaction rate, the reaction temperature in step A is preferably -20°C or higher, and more preferably 0°C or higher. Furthermore, from the viewpoint of suppressing exothermic reaction, it is preferably 60°C or lower, more preferably 40°C or lower, and even more preferably 30°C or lower. From the viewpoint of suppressing heat generation during the reaction, it is preferable to either pre-charge the boron-based reducing agent and solvent in the vessel and add the cyclic acid anhydride in small amounts, or pre-charge the cyclic acid anhydride and solvent in the vessel and add the boron-based reducing agent in small amounts. The reaction time varies depending on the reaction temperature, but including the time for adding the cyclic acid anhydride or boron-based reducing agent, it is typically 6 to 15 hours.

[0018] To neutralize or acidify the reaction solution after the reaction, common mineral acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid, or acidic ion exchange resins can be used. These acids may be used individually or in combination of two or more. When considering the subsequent removal of the acid, hydrochloric acid or acidic ion exchange resins are preferable, while sulfuric acid is preferable when considering ease of handling during large-scale synthesis. The pH of the reaction solution after the addition of the acid is preferably 1 to 7, and more preferably 1 to 4.

[0019] As described above, a reaction solution containing the lactone compound is obtained. The resulting reaction solution may be used directly in step B, or the lactone compound may be recovered from the reaction solution and the recovered lactone compound may be used in step B. One method for recovering lactone compounds is to extract the lactone compounds from the reaction solution using an extraction solvent, and then remove the extraction solvent by distillation. Examples of extraction solvents for extracting lactone compounds include ether-based solvents such as methyl-tert-butyl ether and diisopropyl ether; ketone-based solvents such as methyl-n-propyl ketone, methyl-n-butyl ketone, and methyl isobutyl ketone (hereinafter referred to as MIBK); aromatic hydrocarbon solvents such as toluene and xylene; and ester-based solvents such as ethyl acetate. These may be used individually or in combination of two or more. When prioritizing the recovery rate of lactone compounds and the separation of the two liquid layers, ketone-based solvents, particularly MIBK, are preferred as the extraction solvent.

[0020] The amount of extraction solvent used is not particularly limited, but it is preferably 0.05 times the mass of the reaction solution or more, and preferably 20 times the mass of the reaction solution or less. The extraction process can be performed once or two or more times.

[0021] If necessary, the obtained extract may be washed. Suitable washing solutions include water, weakly alkaline aqueous solutions (such as sodium bicarbonate aqueous solution or sodium carbonate aqueous solution), etc. If necessary, the obtained extract may be diluted or concentrated by removing the extraction solvent. Other solvents may be added after concentration. Examples of solvents used for dilution or solvent substitution are the same as those used for crystallization solvents described above.

[0022] <Process B> In step B, for example, the lactone compound is reacted with formic acid in the presence of an acid catalyst.

[0023] Examples of acid catalysts include perchloric acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid, acidic ion exchange resins, and heteropoly acids. These acid catalysts may be used individually or in combination of two or more. Among these, trifluoromethanesulfonic acid is preferred from the viewpoint of yield and economic efficiency.

[0024] The amount of acid catalyst used is preferably 0.01 to 0.1 times the amount of lactone compound in molar terms. If the amount of acid catalyst used is above the lower limit, the reaction proceeds easily, and if it is below the upper limit, the amount of base required for neutralization after the reaction can be suppressed. Therefore, if the amount of acid catalyst used is within the above range, the yield of formic acid ester is excellent.

[0025] The amount of formic acid used is preferably 2 to 5 times the molar amount of the lactone compound. If the amount of formic acid is above the lower limit, the reaction proceeds easily, and if it is below the upper limit, the amount of base required for neutralization after the reaction can be suppressed. Therefore, if the amount of formic acid used is within the above range, the yield of formic acid ester is excellent.

[0026] The reaction temperature is preferably 80°C or higher. It is also preferable that it be below 101°C, which is the boiling point of formic acid. The reaction time varies depending on the reaction temperature, but it is typically 8 to 20 hours. The lactone compound, formic acid, and acid catalyst may be charged together, but if reaction yield is a priority, it is preferable to pre-mix the lactone compound and formic acid and then dropwise add the acid catalyst.

[0027] As described above, a reaction solution containing formic acid ester is obtained. The formic acid ester may be a mixture of isomers in which the substitution positions of the formyloxy group differ from each other. After the reaction, if necessary, excess formic acid is removed from the reaction solution by distillation, and then the formic acid ester is recovered from the reaction solution and subjected to step C. One method for recovering formic acid esters is to extract the formic acid esters from the reaction solution using an extraction solvent, and then remove the extraction solvent by distillation.

[0028] Examples of extraction solvents for extracting formic acid esters include those similar to those used for extracting lactone compounds. The amount of extraction solvent used is not particularly limited, but it is preferably 0.05 times the mass of the reaction solution or more, and preferably 20 times the mass of the reaction solution or less. The extraction process can be performed once or two or more times. If necessary, the reaction solution or extract may be washed. Suitable washing solutions include water, weakly alkaline aqueous solutions (such as sodium bicarbonate aqueous solution, sodium carbonate aqueous solution, sodium hydroxide aqueous solution, potassium carbonate aqueous solution, etc.).

[0029] <Process C> In step C, the formic acid ester obtained in step B is purified by thin-film distillation. Specifically, the formic acid ester is distilled under reduced pressure using a thin-film distillation apparatus. As the thin-film distillation apparatus, known thin-film distillation apparatuses can be used, such as the Kobe Steel Environmental Solutions Co., Ltd.: 2-03 Wiprene model, and the Shibata Scientific Co., Ltd.: MS-300 molecular distillation apparatus. The following conditions can be used for thin-film distillation: Heating temperature: 150~210℃ Vacuum degree: 0.67~13.33hPa Capacitor temperature (cooling temperature): 5~35℃ Note that the degree of vacuum is measured in absolute pressure.

[0030] As described above, a fraction containing formic acid ester is obtained. The obtained fraction is subjected to step D as "purified formic acid ester". The formic acid ester may be a mixture of isomers in which the substitution positions of the formyloxy group differ from each other. In the purified formic acid ester, a purity of 95% or higher is preferred. The purity is measured by the method described in the examples below. In the purified formic acid ester, the boron content is preferably 5 ppm by mass or less, and more preferably 3 ppm by mass or less, based on 100% by mass of the purified formic acid ester. The boron content is measured by the method described in the examples below.

[0031] <Process D> In step D, (meth)acrylic acid ester is obtained from the formic acid ester purified in step C. Methods for obtaining (meth)acrylic acid esters from formic acid esters include, for example, the following methods (a) or (b). (a) A method of hydrating a formic acid ester and esterifying the resulting alcohol with (meth)acrylic acid. (b) A method for transesterifying a formic acid ester with a (meth)acrylic acid ester. Method (b) is preferred because it yields (meth)acrylic acid ester from formic acid ester in a single step.

[0032] In method (a), when the formic acid ester is hydrated, an alcohol is obtained in which the formyloxy group of the formic acid ester is replaced with a hydroxyl group. The hydration of formic acid esters and the esterification of alcohols with (meth)acrylic acid can be carried out by the methods described in Japanese Patent Publication No. 2002-234882.

[0033] In method (b), the (meth)acrylic acid ester to be transesterified with the formic acid ester (hereinafter also referred to as "raw material (meth)acrylic acid ester") can be represented by the following formula (5). CH2=CR-C(=O)-OZ (5) However, R is a hydrogen atom or a methyl group, and Z is any substituent.

[0034] Examples of Z include alkyl groups having 1 to 3 carbon atoms and alkenyl groups having 2 to 3 carbon atoms. Specific examples include methyl groups, ethyl groups, n-propyl groups, isopropyl groups, and vinyl groups. Of these, methyl or vinyl groups are preferred due to their high reactivity, while isopropyl groups are preferred due to their low byproduct content.

[0035] When formic acid ester and the raw material (meth)acrylic acid ester are transesterified, a (meth)acrylic acid ester represented by formula (1) and a formic acid ester combined by formula (6) below are produced. HC(=O)-OZ (6)

[0036] In transesterification reactions, formic acid esters may be used individually or in combination of two or more. For example, a mixture of two compounds with different formal group bonding positions may be used.

[0037] In the transesterification reaction, the starting material (meth)acrylic acid ester may be used alone or in combination of two or more types. For example, methyl (meth)acrylate and vinyl (meth)acrylate may be used in combination. When using two or more raw material (meth)acrylic acid esters, the two or more raw material (meth)acrylic acid esters may be mixed in advance and reacted with the formic acid ester, or the two or more raw material (meth)acrylic acid esters may be reacted with the formic acid ester sequentially.

[0038] The ratio of the starting material (meth)acrylic acid ester to 1 mole of formic acid ester is preferably 2 to 15 moles, and more preferably 3 to 10 moles. If the ratio of the starting material (meth)acrylic acid ester is above the lower limit, the reaction proceeds sufficiently, and if it is below the upper limit, the time required to remove unreacted starting material (meth)acrylic acid ester from the reaction product after the transesterification reaction is shortened.

[0039] Transesterification reactions are typically carried out in the presence of a catalyst. The catalyst is not particularly limited as long as it promotes the transesterification reaction, but examples include tetraalkoxytitanium compounds such as tetrabutoxytitanium, tetraisopropoxytitanium, and tetramethoxytitanium, dialkyltin oxides such as dibutyltin oxide and dioctyltin oxide, aluminum alkoxylates, and alkali metal alkoxylates. One of these catalysts may be used alone, or two or more may be used in combination.

[0040] As catalysts, tetrabutoxytitanium, tetraisopropoxytitanium, and tetramethoxytitanium are preferred in terms of reactivity, while dibutyltin oxide, dioctyltin oxide, and tetramethoxytitanium are preferred in terms of producing few by-products. Tetramethoxytitanium is more preferred in terms of excellent reactivity and few side reactions, and tetraisopropoxytitanium is even more preferred in terms of excellent reactivity.

[0041] The catalyst may be added all at once or in several portions. If two or more catalysts are used, the entire amount may be added at once or any of the catalysts may be added at any time. The amount of catalyst used is preferably 0.005 to 0.2 moles, and more preferably 0.01 to 0.1 moles, per mole of formic acid ester. If the amount of catalyst used is above the lower limit, the reaction proceeds easily. If the amount of catalyst used is below the upper limit, by-products are less likely to be formed. In addition, the removal of the catalyst after the reaction is easy.

[0042] The reaction temperature for the transesterification reaction is preferably 50 to 150°C, and more preferably 80 to 130°C. If the reaction temperature is above the lower limit, the transesterification reaction is more likely to proceed sufficiently, and if it is below the upper limit, the formation of by-products is more likely to be suppressed.

[0043] The reaction time for the transesterification reaction varies depending on the batch size, catalyst, and reaction temperature, but is preferably 1 to 15 hours, and more preferably 2 to 12 hours. If the reaction time is above the lower limit, the transesterification reaction is more likely to proceed sufficiently, and if it is below the upper limit, the formation of by-products is more likely to be suppressed.

[0044] During a transesterification reaction, high levels of moisture in the system can reduce catalytic activity and increase by-products. Therefore, moisture should be removed from the system as needed before starting the transesterification reaction. The amount of moisture in the system at the start of the transesterification reaction is preferably 1000 ppm by mass or less, more preferably 500 ppm by mass or less, and even more preferably 200 ppm by mass or less.

[0045] There are no particular limitations on the method for removing water from the system, but one example is azeotropic reaction with a high-boiling point solvent such as toluene or methyl methacrylate using a device such as a Dean-Stark trap or decanter. A preferred method is to dissolve the formic acid ester in toluene or methyl methacrylate, and then use a Dean-Stark trap or decanter to heat the toluene or methyl methacrylate under reflux while removing the water from the reaction system, as this method is simple to perform.

[0046] Transesterification reactions are preferably carried out in the presence of a polymerization inhibitor, as this inhibits the polymerization of (meth)acrylic acid esters and other compounds. It is also effective to carry out the reaction while blowing in air or oxygen. Polymerization inhibitors are not particularly limited as long as they inhibit polymerization, but examples include hydroquinone, 4-methoxyphenol, 2,4-dimethyl-6-t-butylphenol, p-benzoquinone, 2,5-diphenyl-p-benzoquinone, phenothiazine, N-nitrosodiphenylamine, copper salts, metallic copper, and 2,2,6,6-tetramethylpiperidine-1-oxyl.

[0047] The transesterification reaction may be carried out in the presence of a solvent. The solvent is not particularly limited, but examples include toluene, heptane, and hexane.

[0048] After the transesterification reaction is complete, the reaction mixture is concentrated and purified to recover the (meth)acrylic acid ester. After the transesterification reaction is complete, the reaction mixture may be concentrated and purified as is; however, in this case, catalyst residue may remain after purification. Therefore, it is preferable to remove the catalyst from the reaction mixture before purification.

[0049] Examples of methods for removing the catalyst include the following: • A method of washing the reaction solution with water or an alkaline aqueous solution such as sodium hydroxide, potassium hydroxide, sodium carbonate, or sodium bicarbonate, or by neutralizing and washing with water. A method in which an alkaline powder such as sodium carbonate, sodium bicarbonate, or magnesium oxide is added to the reaction solution, stirred, and then the neutralized salt is filtered. A method of dissolving a catalyst by adding water and an acid such as hydrochloric acid or sulfuric acid to the reaction solution. Of these methods, the method of dissolving the catalyst by adding water and acid to the reaction solution is preferred because the process is simple and yields a good result.

[0050] Tetraalkoxytitanium compounds, widely used as catalysts, generate a large amount of insoluble matter when in contact with water, and dissolving this insoluble matter is difficult. On the other hand, tetraalkoxytitanium compounds also generate insoluble matter when in contact with acid, but since this insoluble matter is a water-soluble salt, it dissolves when water is added. Therefore, in order to dissolve tetraalkoxytitanium compounds, it is preferable to add acid to the reaction solution and then add water. The acid added at this time is not particularly limited, but strong acids such as sulfuric acid, nitric acid, and hydrochloric acid are preferred because they can be used in small quantities, and sulfuric acid is particularly preferred because it is easy to handle.

[0051] Before dissolving the catalyst, the reaction mixture may be diluted with an organic solvent as needed. Suitable organic solvents for dilution include toluene, benzene, hexane, cyclohexane, ethyl acetate, diethyl ether, and diisopropyl ether. Among these, toluene, ethyl acetate, and diethyl ether are preferred due to their high extraction efficiency and reduced solvent usage, while toluene and ethyl acetate are more preferred due to their superior yield. After dissolving the catalyst, concentrate the reaction mixture as needed.

[0052] Purification methods include column chromatography and distillation. Vacuum distillation, such as simple distillation and thin-film distillation, is preferred because it can reduce impurities such as solvents and trace metals. During purification, polymerization may occur, so it is preferable to include a polymerization inhibitor. The polymerization inhibitor is not particularly limited as long as it suppresses polymerization; the same type used in transesterification reactions can be used. Performing purification while blowing in air or oxygen is also effective in suppressing polymerization.

[0053] (Meth)acrylic acid esters are obtained as described above. (Meth)acrylic acid esters may be a mixture of isomers in which the substitution positions of the (meth)acryloyloxy group (CH2=C(R)-C(=O)-O-) are different from each other. (Meth)acrylic acid esters contain boron as an impurity derived from boron-based reducing agents. The boron content of (meth)acrylic acid esters is preferably 5 ppm by mass or less, and more preferably 3 ppm by mass or less, per 100% by mass of (meth)acrylic acid ester. The boron content is measured by the method described in the examples below.

[0054] In the manufacturing method described above, a boron-based reducing agent is used in the manufacturing process, and by purifying the formic acid ester by thin-film distillation, a (meth)acrylic acid ester with high purity, low viscosity, and low boron content can be obtained. Furthermore, because a boron-based reducing agent is used to reduce the cyclic acid anhydride, the yield of the lactone compound is superior compared to when other reducing agents are used, and the final yield of the (meth)acrylic acid ester is also superior.

[0055] Furthermore, (meth)acrylic acid esters in which X in formula (1) is an oxygen atom or a sulfur atom are also known as raw materials for electronic materials. However, in this case, due to their high polarity, purification by thin-film distillation is difficult, and it is considered that a different purification method must be applied to reduce the boron content. [Examples]

[0056] The following describes embodiments of the present invention, but the present invention is not limited to these embodiments.

[0057] (a) Purity The purity of each compound was calculated from the peak area measured using a gas chromatograph (hereinafter referred to as "GC") (instrument name: Shimadzu Corporation: GC2010Plus) using the following formula. Purity (%)=(A / B)×100 Here, A represents the total peak area of ​​the target product, and B represents the total peak area of ​​all products.

[0058] (b) Viscosity The viscosity of each compound was measured at 25°C using a conical plate rotational viscometer (device name: Toki Sangyo Co., Ltd.: TVE-35H).

[0059] (c) Boron content The boron content of each compound was measured using an inductively coupled plasma mass spectrometer (hereinafter referred to as "ICP-MS").

[0060] (d) Distillation yield The distillation yield was calculated using the following formula. Distillation yield (%) = (C / D) × 100 Here, C represents the mass of the target product, and D represents the mass of the reference raw material.

[0061] (Example 1) A suspension was obtained by gradually adding 49.2 g (1.30 mol) of sodium borohydride to 438.6 g of N,N-dimethylformamide at room temperature and stirring. To this suspension, a solution of 328.4 g (2.0 mol) of 5-norbornene-2,3-dicarboxylic acid anhydride uniformly dissolved in 584.8 g of N,N-dimethylformamide was added dropwise, taking care to avoid exothermic reactions, and the mixture was aged at room temperature after addition. After aging, 200 g of 10% by mass aqueous sulfuric acid solution was added, taking care to avoid exothermic reactions, and the reaction mixture was extracted with MIBK. The combined organic phase was washed with water and the solvent was removed by distillation, yielding a white solid 4-oxatricyclo[5.2.1.0 2,6252.0 g of ]-8-decene-3-one was obtained (purity 97.0% by mass, 1.62 mol, yield 81% by GC measurement). 4-Oxatricyclo[5.2.1.0 2,6 252.0 g of ]-8-decen-3-one (purity 97.0% by mass, 1.62 mol) was uniformly dissolved in 299.4 g (6.50 mol) of formic acid, to which 12.0 g (0.08 mol) of trifluoromethanesulfonic acid was added while taking care to avoid exothermic reaction. This liquid was slowly heated under reflux conditions, and the result was obtained on a GC chart from 4-oxatricyclo[5.2.1.0 2,6 Reflux was continued until the peak of ]-8-decen-3-one almost disappeared. After refluxing was stopped, the reaction mixture was cooled to room temperature, saturated sodium bicarbonate aqueous solution was added carefully to avoid foaming, and the mixture was extracted with ethyl acetate. The combined organic phases were washed with 20% by mass saline solution and the solvent was removed by distillation, resulting in a dark brown, highly viscous liquid from which unpurified 8-formyloxy-3-oxatricyclo[5.3.1.0 1,5 ] Decane-2-one (hereinafter referred to as "8-OTDF") and 9-formyloxy-3-oxatricyclo[5.3.1.0 1,5 A mixture of decane-2-one (hereinafter referred to as "9-OTDF") and 200 g was obtained. The combined purity of 8-OTDF and 9-OTDF in this unrefined mixture was measured by GC and found to be 92.6% by mass (0.94 mol, yield 58%). The viscosity of this unrefined mixture at 25°C was 2376 mPa·s, and its boron content was 1805 ppm by mass.

[0062] Of the above mixture of unpurified 8-OTDF and 9-OTDF, 100.0 g (purity 92.6% by mass, 0.47 mol) was subjected to thin-film distillation using Shinko Environmental Solutions 2-03 type Wiprene under the following conditions, yielding 73.8 g of a mixture of purified 8-OTDF and 9-OTDF as a pale yellow transparent liquid. The purity of the purified mixture of 8-OTDF and 9-OTDF was measured by GC and found to be 99.0% by mass (0.37 mol, distillation yield 79%). The viscosity of this purified mixture at 25°C was 748 mPa·s, and its boron content was 3.2 ppm by mass. <Thin film distillation conditions> Heating temperature: 200℃ Vacuum degree: 2.67hPa Feed rate: 6.3g / min Capacitor temperature: 25℃

[0063] A pale yellow, transparent liquid mixture of 8-OTDF and 9-OTDF, purified by thin-film distillation, was mixed with 73.8 g (99.0% by mass purity, 0.37 mol), 149.0 g (1.49 mol) of methyl methacrylate, 75 mg (0.60 mmol) of 4-methoxyphenol, 73.8 g of toluene, and 3.2 g (0.011 mol) of titanium tetraisopropoxide. The mixture was refluxed while removing the methanol-containing distillate, and reflux was continued for 8 hours until the peak of the 8-OTDF and 9-OTDF mixture almost disappeared on the GC chart. After refluxing, the reaction mixture was cooled to room temperature and washed with 12.2 g (0.12 mol) of sulfuric acid, 36.5 g of toluene, and 73.8 g of water. Subsequently, the organic phase was washed sequentially with 5% sodium bicarbonate solution and water, and the solvent was removed by distillation. The result was 8-methacryloyloxy-4-oxatricyclo[5.2.1.0 2,6 ] Decane-3-one and 9-methacryloyloxy-4-oxatricyclo[5.2.1.0 2,6 A mixture of decane-3-one was obtained in a quantity of 78.9 g (purity 97.0% by mass, 0.32 mol, yield 87%) as determined by GC. The boron content of this mixture was 0.8 ppm by mass.

[0064] (Comparative Example 1) In Example 1, the same procedure was followed except that the mixture of unpurified 8-OTDF and 9-OTDF was not purified by thin-film distillation. 2,6 ] Decane-3-one and 9-methacryloyloxy-4-oxatricyclo[5.2.1.02,6 A mixture with decan-3-one was obtained. That is, 100.0 g (purity 92.6% by mass, 0.47 mol) of a mixture of 8-OTDF and 9-OTDF, which is an unpurified dark brown liquid, 188.2 g (1.88 mol) of methyl methacrylate, 94 mg (0.76 mmol) of 4-methoxyphenol, 100.0 g of toluene, and 4.1 g (0.014 mol) of titanium tetraisopropoxide were mixed, and while extracting the distillate containing methanol, the mixture was brought to a reflux state and reflux was continued for 24 hours until the peaks of the mixture of 8-OTDF and 9-OTDF almost disappeared on the GC chart. After completion of the reflux, the reaction solution was cooled to room temperature and washed by adding 15.7 g (0.16 mol) of sulfuric acid, 50.0 g of toluene, and 100.0 g of water. Subsequently, the organic phase was successively washed with 5% aqueous sodium hydrogen carbonate solution and water, and the solvent was distilled off, and 8-methacryloyloxy-4-oxatricyclo[5.2.1.0 2,6 A mixture with decan-3-one and 9-methacryloyloxy-4-oxatricyclo[5.2.1.0 2,6 A 101.4 g mixture with decan-3-one (purity 78.0% by mass, 0.33 mol, yield 71%) was obtained by GC measurement. The boron content of this mixture was 397 ppm by mass. As a result, the unpurified mixture of 8-OTDF and 9-OTDF was more viscous and difficult to handle at room temperature compared to the one purified by thin-film distillation, and the reaction time of the transesterification reaction was long. Furthermore, the reaction yield of the obtained mixture of 8-methacryloyloxy-4-oxatricyclo[5.2.1.0 2,6 A mixture with decan-3-one and 9-methacryloyloxy-4-oxatricyclo[5.2.1.0 2,6 The reaction yield of the mixture with decan-3-one was low and the boron content was high.

Industrial Applicability

[0065] According to the production method of the present invention, a (meth)acrylic acid ester having a lactone structure and a low boron content can be produced. The obtained (meth)acrylic acid ester is useful as a raw material for electronic materials, for example, a monomer as a raw material for the constituent resin of a resist.

Claims

[Claim 1] A step of reducing a cyclic acid anhydride represented by the following formula (2) with a boron-based reducing agent to obtain a lactone compound represented by the following formula (3), A step of adding formic acid to the lactone compound to obtain a formic acid ester represented by the following formula (4): A step of purifying the formic acid ester by thin-film distillation, and The process includes a step of obtaining a (meth)acrylic acid ester represented by the following formula (1) from the purified formic acid ester, A method for producing (meth)acrylic acid ester, wherein the heating temperature of the thin-film distillation is 150 to 210°C and the vacuum level of the thin-film distillation is 0.67 to 13.33 hPa. 【Chemistry 1】 However, X represents a methylene group or an ethylene group, and R represents a hydrogen atom or a methyl group.

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