TWI570113B - Preparing method of glycidyl methacrylate - Google Patents

Description

Method for producing glycidyl methacrylate

The present invention relates to a process for producing glycidyl (meth)acrylate.

In the case where epichlorohydrin is reacted with an alkali metal (meth) acrylate in the presence of a catalyst to produce glycidyl (meth)acrylate, it is known that the water content of the reaction liquid is a by-product. The influence of the generation (Patent Document 1). When the amount of water in the reaction liquid is large, it is known that various side reactions such as hydrolysis occur, and it is generally considered that the amount of water is small. According to Patent Document 1, the amount of water in the reaction liquid is in the range of 600 ppm by mass to 1600 ppm by mass, and by-products can be suppressed to produce glycidyl (meth)acrylate. Further, glycidyl (meth)acrylate means glycidyl methacrylate or glycidyl acrylate.

Among the above-mentioned by-products, various chlorine-containing impurities derived from epichlorohydrin are known. The chlorine-containing impurities close to the boiling point of glycidyl (meth)acrylate cannot be sufficiently removed by distillation, and therefore are incorporated into the product to deteriorate the quality of the product.

Further, since glycidol produced by epichlorohydrin by-product is indicated to be toxic (carcinogenic), a technique for reducing glycidol is sought. Set the water content of the reaction solution to In the case of the range described in the patent document 1, although the amount of generation of glycidol is reduced, it is not sufficiently reduced, and after distillation, gas chromatography (GC) analysis includes 0.1% by mass. The above situation.

On the other hand, epichlorohydrin is reacted with an alkali metal (meth)acrylate in the presence of a catalyst, and the by-produced alkali metal chloride is removed from the obtained crude glycidyl (meth)acrylate reaction solution. The method is known by a method of filtration or by a method of washing with water. The method disclosed in Patent Document 2 to Patent Document 4 is known by the method of water washing.

Further, epichlorohydrin and (meth)acrylic acid are reacted in the presence of a catalyst, and an aqueous alkali solution is added to the obtained mixture of chloropropylpropyl (meth)acrylate and glycidyl (meth)acrylate. A method disclosed in Patent Document 5 is known as a method for obtaining crude glycidyl (meth)acrylate.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 07-2818

[Patent Document 2] Japanese Patent Laid-Open No. Hei 04-187682

[Patent Document 3] Japanese Patent Laid-Open No. 09-59268

[Patent Document 4] Japanese Patent Laid-Open No. 55-17307

[Patent Document 5] GB1155543

In the method for producing glycidyl (meth)acrylate, it is difficult to sufficiently reduce the chlorine-containing impurities generated by the secondary, and the total chlorine content in the product is 1000 ppm by mass or more. The chloropropenyl acrylate was mixed in an amount of 0.1% by mass or more in the GC analysis.

Further, in the method for cleaning glycidyl (meth)acrylate, when the crude glycidyl (meth)acrylate reaction solution after the reaction is washed with water to remove the alkali metal chloride, the glycidol is also partially dissolved in the water to be removed. . Since glycidol is relatively high in polarity, it is extracted to the aqueous layer to some extent by washing with water, but the degree of removal is not sufficient, and it is not sufficiently removed in the subsequent distillation purification, and is present in the distilled product in the GC. In the analysis, 0.1% by mass or more was mixed.

An object of the present invention is to provide a glycidyl (meth)acrylate having a small content of impurities.

The method for producing glycidyl (meth)acrylate of the present invention comprises the steps of: reacting epichlorohydrin with an alkali metal (meth)acrylate or (meth)acrylic acid in the presence of a catalyst; and The reaction liquid obtained by the reaction is subjected to a step of washing with water at a temperature of -13 ° C or more and less than 20 ° C.

According to the present invention, glycidyl (meth)acrylate having a low impurity content can be provided.

The method for producing glycidyl (meth)acrylate of the present invention includes the following a step of reacting epichlorohydrin with an alkali metal salt of (meth)acrylic acid or (meth)acrylic acid in the presence of a catalyst; and a reaction liquid obtained by the reaction at -13 ° C or more and less than 20 ° C The step of washing with water at a temperature. In the method of the present invention, the content of glycidol as a by-product in the water washing step can be sufficiently reduced. Thereby, high quality glycidyl (meth)acrylate is obtained.

Further, in the method of the present invention, in the reaction step, the water content of the reaction liquid at the time of the addition of the raw material is preferably 2,000 ppm by mass or more and 15,000 ppm by mass or less. When the amount of the water in the reaction liquid at the time of the addition of the raw material is within the above range, the amount of the chlorine-containing impurities to be described later in the reaction step can be reduced.

The details of each step of the method of the present invention are shown below.

[Reaction step]

The process of the present invention comprises the step of reacting epichlorohydrin with an alkali metal (meth)acrylate or (meth)acrylic acid in the presence of a catalyst. In the present invention, glycidyl (meth)acrylate is produced by the reaction of epichlorohydrin with an alkali metal (meth)acrylate or (meth)acrylic acid. Further, (meth) acrylate means methacrylate or acrylate, (meth)acrylic acid alkali metal salt means methacrylic acid alkali metal salt or acrylic acid alkali metal salt, and (meth)acrylic acid means methacrylic acid or acrylic acid.

The method for producing epichlorohydrin is not particularly limited, and a known method can be used. For example, a method in which propylene or allyl alcohol is chlorinated, and dichlorohydrin is used to obtain epichlorohydrin by dehydrochlorination.

The (meth)acrylic acid alkali metal salt is not particularly limited and can be used, for example. Base) sodium acrylate, potassium (meth) acrylate, lithium (meth) acrylate, and the like. These compounds may be used alone or in combination of two or more.

The (meth)acrylic acid alkali metal salt is prepared by neutralization of (meth)acrylic acid with an alkali metal hydroxide. (Meth)acrylic acid means acrylic acid or methacrylic acid. The method for producing (meth)acrylic acid is not particularly limited, and a known production method can be used. For example, a so-called collapse chip connection (C3) or a controlled collapse chip connection (C4) oxidation method, an acetone cyanohydrin method (ACH method) or an amine-based nitrogen water can be cited. (amino nitrogen hydrolysis method, AN hydrolysis method). The alkali metal hydroxide is not particularly limited, and is preferably sodium hydroxide, potassium hydroxide, lithium hydroxide or the like. These compounds may be used alone or in combination of two or more.

The mixing ratio of the (meth)acrylic acid to the alkali metal hydroxide is preferably from 1 mol to the (meth)acrylic acid, and the alkali metal hydroxide is from 0.9 mol to 1.1 mol, more preferably from 0.95 mol to 1.05 mol. The reason for this is that the closer the reaction liquid obtained is to neutral, the more the side reaction at the time of synthesis of glycidyl (meth)acrylate is suppressed.

A solvent can be used when neutralizing (meth)acrylic acid with an alkali metal hydroxide. From the viewpoint of solubility, the solvent is preferably an alcohol such as methanol or water. In the case of using a solvent, the solvent can be removed after neutralization. A known method can be used for the solvent removal method, and for example, a distillation or a spray dryer or the like can be used.

The temperature of the reaction liquid at the time of neutralization is preferably 0 ° C or more and 40 ° C or less. The water can be prevented from freezing by the temperature of the reaction liquid being 0 ° C or higher. In addition, by the reaction liquid The temperature is 40 ° C or less, and the mixing of the strong alkaline aqueous solution can be carried out safely. The time for the neutralization reaction is preferably 10 minutes or longer and 1 hour or shorter. The neutralization reaction can be sufficiently carried out by allowing the neutralization reaction time to be 10 minutes or longer. Further, since the time for the neutralization reaction is 1 hour or shorter, the working time can be shortened, and therefore it is industrially preferable.

The reaction of epichlorohydrin with an alkali metal (meth)acrylate or (meth)acrylic acid is carried out in the presence of a catalyst. As the catalyst, a known catalyst can be used, and for example, a quaternary ammonium salt or an ion exchange resin having the quaternary ammonium salt can be used. For the quaternary ammonium salt, for example, tetramethylammonium chloride, tetramethylammonium bromide, tetraethylammonium chloride, tetraethylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium bromide, or the like can be used. Tetraalkylammonium salt. A commercially available strong basic anion exchange resin can be used as the ion exchange resin. These compounds may be used alone or in combination of two or more.

In the reaction of epichlorohydrin with an alkali metal (meth)acrylate or (meth)acrylic acid and a neutralization reaction of (meth)acrylic acid with an alkali metal hydroxide, a polymerization inhibitor can be used in order to suppress polymerization. As the polymerization inhibitor, a known polymerization inhibitor can be used. As the polymerization inhibitor, for example, a phenol system such as hydroquinone or p-methoxyphenol, 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (4-hydroxy) can be used. N-oxyl groups such as -2,2,6,6-tetramethylpiperidine-N-oxyl, HO-TEMPO). These compounds may be used alone or in combination of two or more. Further, in order to prevent polymerization, it is preferred to foam oxygen or air during the reaction.

The reaction temperature in the reaction of epichlorohydrin with an alkali metal salt of (meth)acrylic acid or (meth)acrylic acid is preferably 70° C. or higher and 130° C. or lower, more preferably 80° C. or higher. Below 120 °C. A sufficient reaction rate is obtained by a reaction temperature of 70 ° C or more. Further, by the reaction temperature being 130 ° C or lower, the formation of by-products can be suppressed.

The amount of the catalyst used in the reaction of epichlorohydrin with an alkali metal salt of (meth)acrylic acid or (meth)acrylic acid is preferably 0.01 mol based on 1 mol of the (meth)acrylic acid alkali metal salt or (meth)acrylic acid. The above is preferably 10 mol or less, more preferably 0.05 mol or more and 5 mol or less. A sufficient reaction rate is obtained by the amount of the catalyst being 0.01 mol or more with respect to 1 mol of the (meth)acrylic acid alkali metal salt or (meth)acrylic acid. In addition, the amount of the catalyst is 10 mol or less based on 1 mol of the (meth)acrylic acid alkali metal salt or (meth)acrylic acid, and generation of by-products can be suppressed.

The amount of the polymerization inhibitor used in the reaction of epichlorohydrin with an alkali metal salt of (meth)acrylic acid or (meth)acrylic acid is preferably 10 mass with respect to the alkali metal salt of (meth)acrylic acid or (meth)acrylic acid. Ppm or more and 10,000 mass ppm or less. When the amount of the polymerization inhibitor is 10 ppm by mass or more, the polymerization can be sufficiently suppressed. In addition, when the amount of the polymerization inhibitor is 10,000 ppm by mass or less, occurrence of deterioration in quality due to coloring or the like of the product can be suppressed.

In the reaction of epichlorohydrin with an alkali metal salt of (meth)acrylic acid or (meth)acrylic acid, when the amount of water in the reaction liquid at the time of addition of a raw material is large, it is known that the amount of formation of by-products increases. However, in the case where the amount of water is small, there is also a by-product which increases the amount of production. In the present invention, the water content of the reaction liquid when the raw material is added is in the range of 2,000 ppm by mass or more and 15,000 ppm by mass or less, and in particular, generation of specific chlorine-containing impurities can be suppressed, and generation of other by-products can be suppressed. Say, also The comparison can be suppressed, so it is preferable. The water content of the reaction liquid at the time of the addition of the raw material is more preferably 2,500 ppm by mass or more and 10,000 ppm by mass or less, and particularly preferably 3,000 ppm by mass or more and 8,000 ppm by mass or less. In addition, the water content of the reaction liquid at the time of the addition of the raw material means the amount of water contained in the reaction liquid in which all of the raw materials such as epichlorohydrin, alkali metal (meth)acrylate, or (meth)acrylic acid and a catalyst are added. . Further, the moisture content of the reaction liquid at the time of the addition of the raw material is a value obtained by analysis using a Karl Fischer moisture meter.

In particular, the above-mentioned chlorine-containing impurities which are formed by the following formula (1) include propylene chloride (meth)acrylate.

R is hydrogen or methyl

In the above formula (1), R represents hydrogen or a methyl group. Since the (meth)acrylic acid propylene acrylate represented by the above formula (1) has a small difference in boiling point from the glycidyl (meth)acrylate, it cannot be separated during distillation and is mixed into the product. In the region where the amount of water in the reaction liquid at the time of the addition of the raw material is small, the inventors of the present invention have found that the amount of secondary generation of the (meth)acrylic acid propylene chloride represented by the above formula (1) is rather increased. On the other hand When the amount of the reaction liquid in the case where the raw material is added is in the above range, the amount of secondary generation of the (meth)acrylic acid propylene chloride represented by the above formula (1) can be reduced, and the distillation after distillation can be reduced. The amount of mixing in the liquid is also reduced, and the amount of total chlorine in the distillate is reduced. For example, in the case where the amount of the (meth)acrylic acid propylene chloride in the distillate is 0.06% with respect to the area of the GC area with respect to the glycidyl methacrylate, the total chlorine amount is about 390 ppm by mass.

Further, when the amount of water is increased, the adjustment of the amount of water in the reaction liquid at the time of adding the raw material can be adjusted by adding pure water, ion-exchanged water or the like. On the other hand, in the case of reducing the amount of water, it can be adjusted by removing the moisture in the raw material, i.e., epichlorohydrin or alkali metal (meth)acrylate. The removal of moisture in epichlorohydrin can be carried out, for example, using a molecular sieve or distillation. Further, the removal of moisture in the (meth)acrylic acid alkali metal salt can be carried out, for example, by heating under reduced pressure. The moisture removal of (meth)acrylic acid can use molecular sieves or distillation.

[washing step]

The method of the present invention comprises the reaction solution obtained by the reaction of epichlorohydrin with an alkali metal (meth)acrylate or the reaction of epichlorohydrin with (meth)acrylic acid at a temperature of -13 ° C or more and less than 20 ° C. The step of washing under water. In addition to the glycidyl (meth)acrylate, an alkali metal chloride, a catalyst, the remaining epichlorohydrin, a by-product, and the like are present in the reaction liquid in which the reaction is completed. By washing the reaction liquid with washing water, the alkali metal chloride, the catalyst, and the specific by-products can be dissolved and separated in the aqueous layer to be separated and removed.

The washing water used for the water washing may use water or an aqueous solution in which a basic compound is dissolved. The washing water is preferably an aqueous solution in which a basic compound is dissolved. By using an aqueous solution in which a basic compound is dissolved as the washing water, the side reaction at the time of the water washing step can be further suppressed. In particular, when (meth)acrylic acid is used as a raw material, by using an aqueous solution in which a basic compound is dissolved, the amount of glycidyl (meth)acrylate can be increased, and side reactions can be suppressed. The basic compound is not particularly limited, and examples thereof include an alkali metal hydroxide, an alkali metal carbonate, and an alkali metal hydrogencarbonate. Specific examples thereof include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogencarbonate, and potassium hydrogencarbonate. These compounds may be used alone or in combination of two or more.

The amount of the basic compound contained in the washing water is preferably 0 parts by mass or more and 50 parts by mass or less, more preferably 0.1 parts by mass or more and 30 parts by mass or less, and particularly preferably 100 parts by mass of the water constituting the washing water. 0.2 parts by mass or more and 20 parts by mass or less. When the amount of the basic compound is within the above range, the formation of by-products can be sufficiently suppressed.

The amount of the washing water used in the water washing step is preferably an amount which can sufficiently dissolve the alkali metal chloride and the catalyst. Specifically, it is added in the case where the alkali metal hydroxide or the (meth)acrylic acid and the epichlorohydrin are added after the neutralization of the (meth)acrylic acid and the alkali metal hydroxide, and then neutralized and washed with water. The amount of the alkaline compound is preferably 1 g or more, and the amount of the washing water is 160 g or more and 2000 g or less, more preferably 180 g or more and 1,500 g or less. When the amount of the washing water is 160 g or more, the alkali metal chloride and the catalyst can be sufficiently dissolved. In addition, the productivity is improved by the amount of the washing water being 2000 g or less.

The inventors of the present invention have found that the extraction efficiency of glycidol as a by-product in the aqueous layer changes by the temperature of the reaction liquid in the water washing step. In the present invention, the reaction liquid is washed with water at a temperature of -13 ° C or more and less than 20 ° C. The temperature of the reaction liquid is preferably -10 ° C or higher and 18 ° C or lower, more preferably -8 ° C or higher and 15 ° C or lower, and particularly preferably -5 ° C or higher and 15 ° C or lower. When the temperature of the reaction liquid is -13 ° C or more, the cooling energy cost can be reduced. On the other hand, when the temperature of the reaction liquid is 20 ° C or lower, the extraction effect of glycidol in the aqueous layer is improved, and glycidol can be sufficiently removed. Further, since the water layer is dissolved in salt or impurities, it exists in a region which is not frozen below 0 °C.

After the temperature of the reaction liquid is set to be in the range of -13 ° C or more and less than 20 ° C, washing water is added to the reaction liquid, and the temperature of the mixed liquid is also controlled to be in the range of -13 ° C or more and less than 20 ° C during mixing. If the temperature of the mixed solution is within an appropriate range, the temperature can be controlled without particular control. Further, the reaction liquid may be cooled, and washing water may be added to the reaction liquid, and the temperature of the mixed liquid may be controlled within a range of -13 ° C or more and less than 20 ° C during mixing, and if the temperature of the mixed liquid is within an appropriate range, It can be carried out without special control of the temperature. When the temperature of the reaction liquid is in the range of -13 ° C or more and less than 20 ° C, the mixing may be constant or not constant.

When washing with water, a known stirring method can be used. For example, the reaction liquid and the washing water can be sufficiently stirred and mixed using a stirrer equipped with a stirring blade. The stirring time is not particularly limited, and may be, for example, 3 minutes or longer and 60 minutes or shorter.

After mixing the reaction liquid and the washing water, the mixture is allowed to stand and can be divided. It is separated from the organic layer and the water layer. The organic layer can be purified by a distillation step as follows.

[Distillation step]

The method of the present invention may comprise the step of subjecting the organic layer to a distillation. Glycidyl (meth)acrylate can be obtained by subjecting the organic layer to a distillation. The distillation of the organic layer is carried out by a known method. In order to obtain high-purity glycidyl (meth)acrylate, it is preferred to carry out rectification using a column. The distillation may be a batch type or a continuous type, and the following batch-type precision distillation will be described.

Since glycidyl (meth)acrylate is a polymerizable monomer, it is possible to suppress polymerization by performing distillation under reduced pressure at a lower temperature. From the above viewpoints, the temperature of the distillation pot is preferably 160 ° C or lower, more preferably 150 ° C or lower. On the other hand, from the viewpoint of distillation efficiency, the temperature of the distillation pot is preferably 60 ° C or higher, more preferably 70 ° C or higher. Further, from the viewpoint of the pressure reduction limit, the degree of pressure reduction is preferably 0.1 kPa or more, and more preferably 0.5 kPa or more. On the other hand, from the viewpoint of lowering the temperature, the degree of pressure reduction is preferably 50 kPa or less, and more preferably 30 kPa or less.

In order to suppress polymerization, a known polymerization inhibitor can be supplied into the distillation pot and in the column. As the polymerization inhibitor, for example, a phenol system such as hydroquinone or p-methoxyphenol, 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (4-hydroxy-2, can be used. N-oxyl groups such as 2,6,6-tetramethylpiperidine-N-oxyl, HO-TEMPO). These compounds may be used alone or in combination of two or more. Further, in order to prevent polymerization, it is preferred to foam oxygen or air during distillation.

In the rectification operation using a column, a known method can be used. A known device such as a tray or a packed column using a filler can be used in the column. Purity can be increased by controlling the reflux ratio in the distillation operation. Specifically, from the viewpoint of ensuring purity and productivity, the reflux is preferably in the range of 0.1 to 10, more preferably in the range of 0.3 to 3.

[Examples]

Hereinafter, the present invention will be described in detail by way of examples, but the invention is not limited thereto. The quantitative analysis of each compound in the examples and the comparative examples was carried out by gas chromatography (GC).

The total amount of chlorine (ppm) in the distillate was heated to 100 ° C to 900 ° C by using a sample burning device QF-02 (trade name, manufactured by Mitsubishi Chemical Corporation). After combustion, the gas is absorbed by the absorption tube, and then analyzed by ion chromatography (IC) to perform quantification.

(Example 1)

As a polymerization inhibitor, 0.04 g of 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxybenzoate radical was dissolved in 387.4 g (4.5 mol) of methacrylic acid. This solution was mixed with an aqueous solution obtained by dissolving 180 g (4.5 mol) of sodium hydroxide in 420 g of water. The mixture was spray dried using hot air. Thereby, sodium methacrylate was obtained.

A 2 L flask equipped with a thermometer, an air introduction tube, a stirring blade, and a cooling tube was prepared. To the flask, 221.8 g (2.05 mol) of the above sodium methacrylate and 0.925 g (0.008 mol) of trimethylammonium chloride as a catalyst were added as a polymerization inhibitor. The 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxybenzoate radical was 0.023 g, and epichlorohydrin 990 g (10.7 mol). The moisture content of the reaction liquid at the time of raw material addition was analyzed by the Karl Fischer method using a moisture meter (trade name: CA-21) manufactured by Mitsubishi Chemical Corporation, and it was 4460 mass ppm. Air was introduced into the flask at 10 ml/min, and the reaction liquid was heated to 90 ° C in an oil bath while stirring the reaction liquid. After the temperature of the reaction solution reached 90 ° C, heating was continued for 2 hours so that the temperature of the reaction liquid reached 89 ° C to 91 ° C. The reaction solution was then cooled to 10 °C. While adjusting the temperature of the reaction liquid to 10 ° C, 440 g of a 0.57 mass% sodium hydroxide aqueous solution was mixed, and the mixture was stirred at a stirring speed of 250 rpm for 15 minutes in a glass vessel equipped with a stirring blade, and the reaction liquid was washed. The solution was then pipetted into a separatory funnel and allowed to stand for 30 minutes for stratification. As a result of GC analysis of the washed organic layer at this time, the area percentage of chloropropenyl methacrylate (CPMA) was 0.06% (relative to glycidyl methacrylate (GMA), below The same), the area percentage of glycidol was 0.46%.

Also, a reaction step and a water washing step are additionally carried out. 2142 g of the solution of the two batches of the organic layer obtained by the above was added to a flask equipped with an Oldershaw distillation column equipped with a 5-stage tray, and subjected to precision distillation. After the remaining epichlorohydrin was distilled off and recovered, the main fraction was distilled off at an internal temperature of 94 ° C to 126 ° C, an overhead temperature of 69 ° C to 82 ° C, a pressure of 1.33 kPa to 2.40 kPa, and a reflux ratio of 1. Thereby, 402 g of glycidyl methacrylate was obtained. CPMA in distilled distillate The area percentage was 0.06%, and the area percentage of glycidol was 0.06%. Further, the amount of total chlorine in the distilled distillate was analyzed and found to be 388 ppm by mass. The results are shown in Table 1.

(Example 2 to Example 10 and Comparative Example 1 to Comparative Example 10)

The reaction step and washing were carried out in the same manner as in Example 1 except that the water content of the reaction liquid when the raw material in the reaction step was added and the temperature of the reaction liquid in the water washing step were changed to the values shown in Table 1 and Table 2. The steps and the distillation steps were carried out for various analyses. The results are shown in Table 1 and Table 2. Further, in the case where the amount of water is increased, the adjustment of the amount of water in the reaction liquid at the time of adding the raw material can be adjusted by adding pure water. On the other hand, in the case of reducing the amount of water, it is adjusted by removing the water in the raw material, epichlorohydrin or sodium methacrylate. The removal of moisture in epichlorohydrin is carried out using molecular sieves. Further, the removal of moisture in sodium methacrylate is carried out by heating under reduced pressure.

(Comparative Example 11)

The reaction step was carried out in the same manner as in Example 1 except that the water content of the reaction liquid when the raw material in the reaction step was added and the temperature of the reaction liquid in the water washing step were changed to the values shown in Table 2, and then the reaction was carried out. The temperature of the liquid was controlled to -15 ° C, and 440 g of a 0.57 mass% sodium hydroxide aqueous solution was mixed to wash the reaction liquid, but the aqueous solution was frozen and could not be washed.

(Example 11)

A 2 L flask equipped with a thermometer, an air introduction tube, a stirring blade, and a cooling tube was prepared. To the flask, methacrylic acid, 144.64g (1.68mol), resin as a catalyst for the strongly basic ion-exchange (Wako Pure Chemical, Dowex ^TM, 1 × 8,50-100 mesh) washed with acetone and dried The obtained product was 600 g, a 4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxybenzoate radical as a polymerization inhibitor, 0.04 g, and epichlorohydrin 1480.4 g (16.00 mol). Using a moisture meter (trade name: CA-21) manufactured by Mitsubishi Chemical Corporation, the moisture content of the reaction liquid when the raw material was added by the Karlsfeld method was analyzed and found to be 2,100 ppm by mass. Air was introduced into the flask at 10 ml/min, and the reaction liquid was heated to 90 ° C in an oil bath while stirring the reaction liquid. After the temperature of the reaction solution reached 90 ° C, the mixture was further heated and stirred for 15 minutes. The reaction solution was then cooled to 25 ° C and subjected to suction filtration. While further cooling 1063.2 g of the filtrate and controlling at 3 ° C, 560 g of a [3.57 mass% sodium hydroxide + 3.57 mass% sodium carbonate aqueous solution] was mixed to wash the reaction liquid. As a result of performing GC analysis on the washed organic layer at this time, the area percentage of propylene methacrylate (CPMA) was 0.011% (relative to glycidyl methacrylate (GMA), the same below), glycidol The area percentage was 0.892%.

Also, a reaction step and a water washing step are additionally carried out. 2062 g of the solution of the two batches of the organic layer obtained by the above was added to a flask equipped with an Aldrich distillation column equipped with a 5-stage tray, and subjected to precision distillation. After the remaining epichlorohydrin was distilled off and recovered, the main fraction was distilled off at an internal temperature of 93 ° C to 125 ° C, an overhead temperature of 68 ° C to 83 ° C, a pressure of 1.34 kPa to 2.46 kPa, and a reflux ratio of 1. Thereby, 411 g of glycidyl methacrylate was obtained. Area percentage of CPMA in distilled distillate The rate was 0.01%, and the area percentage of glycidol was 0.10%. The results are shown in Table 3.

(Comparative Example 12)

The reaction step, the water washing step, and the distillation step were carried out in the same manner as in Example 11 except that the temperature of the reaction liquid in the water washing step was changed to the value shown in the table, and various analyses were carried out. The results are shown in Table 4.

[Industrial availability]

The glycidyl (meth)acrylate produced by the method of the present invention can be used for various coatings, adhesives, adhesives, various reactive monomers and the like.

Claims (2)

A method for producing glycidyl methacrylate, comprising the steps of: reacting epichlorohydrin with an alkali metal methacrylate or methacrylic acid in the presence of a catalyst; and reacting the reaction obtained by the reaction a step of washing the liquid at a temperature of -13 ° C or more and less than 20 ° C; and reacting the epichlorohydrin with an alkali metal methacrylate or methacrylic acid in the presence of a catalyst, the reaction at the time of the addition of the raw material The water content of the liquid is 2000 mass ppm or more and 15000 mass ppm or less, wherein the alkali metal methacrylate is prepared by neutralizing methacrylic acid with an alkali metal hydroxide, and when methacrylic acid and alkali metal hydrogen are used In the case of mixing the oxide, an alkali metal methacrylate obtained by mixing an alkali metal hydroxide in an amount of from 0.9 mol to 1.1 mol with respect to 1 mol of methacrylic acid is used. The method for producing glycidyl methacrylate according to the first aspect of the invention, wherein a reaction temperature in the reaction of epichlorohydrin with an alkali metal methacrylate or methacrylic acid is 70° C. or higher and 130° C. the following.