JP2013234125A - Method of producing glycidyl (meth)acrylate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide glycidyl (meth)acrylate with a low content of impurities.SOLUTION: A method of producing glycidyl (meth)acrylate includes: a step of reacting epichlorohydrin with (meth)acrylic acid alkali metal salt in the presence of a catalyst; and a step of cleaning the reaction solution thus obtained by the reaction, at -10°C or higher but lower than 20°C with water.

Description

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

  It is known that when glycidyl (meth) acrylate is produced by reacting epichlorohydrin and alkali metal (meth) acrylate in the presence of a catalyst, the amount of water in the reaction solution affects the formation of by-products. (Patent Document 1). It is known that various side reactions such as hydrolysis occur when the amount of water in the reaction solution is large, and it is generally preferred that the amount of water be small. According to Patent Document 1, glycidyl (meth) acrylate can be produced while suppressing side reactions when the water content in the reaction solution is in the range of 600 mass ppm to 1600 mass ppm. In addition, glycidyl (meth) acrylate shows glycidyl methacrylate or glycidyl acrylate.

  Among the by-products, many chlorine-containing impurities derived from epichlorohydrin are known. Chlorine-containing impurities having a boiling point close to that of glycidyl (meth) acrylate cannot be sufficiently removed by distillation, and thus are mixed in the product, thereby reducing the quality of the product.

  In addition, glycidol by-produced from epichlorohydrin has been pointed out to be toxic (carcinogenic), and a technology for reducing glycidol is required. When the water content of the reaction solution is within the range described in Patent Document 1, the amount of by-product of glycidol is reduced, but it cannot be sufficiently reduced. Even after distillation, it can be analyzed by gas chromatography (GC) analysis. It may be contained by 0.1% by mass or more.

  On the other hand, as a method of removing by-produced alkali metal chloride from the crude glycidyl (meth) acrylate reaction liquid obtained by reacting epichlorohydrin and alkali metal (meth) acrylate in the presence of a catalyst, A method by filtration and a method by washing with water are known. As methods for washing with water, methods disclosed in Patent Documents 2 to 4 are known.

Japanese Patent Application Laid-Open No. 07-2818 JP 04-187682 A JP 09-59268 A JP-A-55-17307

  In the production method of glycidyl (meth) acrylate, it is difficult to sufficiently reduce by-product chlorine-containing impurities, the total chlorine content in the product is 1000 mass ppm or more, and chloropropenyl methacrylate is 0.1 mass in GC analysis. % Or more.

  Moreover, in the washing method of glycidyl (meth) acrylate, when the crude glycidyl (meth) acrylate reaction solution after the reaction is washed with water and the alkali metal chloride is removed, glycidol is partially dissolved in water and removed. The Since glycidol is relatively high in polarity, it is extracted to some extent in the aqueous layer by washing with water, but the degree of removal is not sufficient, and it cannot be completely removed by subsequent distillation purification. % Or more may be mixed.

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

  The method for producing glycidyl (meth) acrylate according to the present invention comprises a step of reacting epichlorohydrin and an alkali metal (meth) acrylate in the presence of a catalyst, and a reaction solution obtained by the reaction at −10 ° C. or higher. Washing with water at a temperature of less than 20 ° C.

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

  The method for producing glycidyl (meth) acrylate according to the present invention comprises a step of reacting epichlorohydrin and an alkali metal (meth) acrylate in the presence of a catalyst, and a reaction solution obtained by the reaction at −10 ° C. or higher. Washing with water at a temperature of less than 20 ° C. In the method according to the present invention, the content of glycidol which is a by-product in the water washing step can be sufficiently reduced. Thereby, a high quality glycidyl (meth) acrylate is obtained.

  Further, in the method according to the present invention, in the reaction step, it is preferable that the water content of the reaction liquid at the time of raw material charging is 2000 mass ppm or more and 10,000 mass ppm or less. When the water content of the reaction liquid at the time of raw material charging is within the above range, the amount of chlorine-containing impurities described later that are by-produced in the reaction step can be reduced.

  Hereafter, the detail of each process of the method concerning this invention is shown.

[Reaction process]
The method according to the present invention includes a step of reacting epichlorohydrin with an alkali metal (meth) acrylate in the presence of a catalyst. In the present invention, glycidyl (meth) acrylate is produced by a reaction between epichlorohydrin and an alkali metal (meth) acrylate. In addition, (meth) acrylic acid alkali metal salt shows methacrylic acid alkali metal salt or acrylic acid alkali metal salt.

  The manufacturing method of epichlorohydrin is not specifically limited, A well-known method can be used. For example, a method of chlorinating propylene or allyl alcohol and obtaining epichlorohydrin by dehydrochlorination reaction via dichloropropanol can be mentioned.

  Although it does not specifically limit as (meth) acrylic-acid alkali metal salt, For example, (meth) acrylic-acid sodium, (meth) acrylic-acid potassium, (meth) acrylic-acid lithium, etc. can be used. These may use only 1 type and may use 2 or more types together.

  The (meth) acrylic acid alkali metal salt is prepared by neutralization of (meth) acrylic acid and an alkali metal hydroxide. (Meth) acrylic acid indicates acrylic acid or methacrylic acid. The manufacturing method of (meth) acrylic acid is not specifically limited, A well-known manufacturing method can be used. For example, the so-called C3 or C4 oxidation method, ACH method or AN hydrolysis method can be mentioned. Although it does not specifically limit as an alkali metal hydroxide, Sodium hydroxide, potassium hydroxide, lithium hydroxide, etc. are preferable. These may use only 1 type and may use 2 or more types together.

  The mixing ratio of (meth) acrylic acid and alkali metal hydroxide is preferably 0.9 to 1.1 mol of alkali metal hydroxide with respect to 1 mol of (meth) acrylic acid, and 0.95 to 1 More preferably, it is .05 mol. It is because the side reaction at the time of glycidyl (meth) acrylate synthesis | combination is suppressed, so that the obtained reaction liquid is near neutrality.

  When neutralizing (meth) acrylic acid and alkali metal hydroxide, a solvent may be used. As the solvent, it is preferable to use alcohol such as methanol or water from the viewpoint of solubility. When a solvent is used, the solvent can be removed after neutralization. As a method for removing the solvent, a known method can be used. For example, distillation, a spray dryer or the like can be used.

  The temperature of the reaction solution during neutralization is preferably 0 ° C. or higher and 40 ° C. or lower. When the temperature of the reaction solution is 0 ° C. or higher, water can be prevented from icing. Further, when the temperature of the reaction solution is 40 ° C. or less, the strong basic aqueous solution can be mixed safely. The neutralization reaction time is preferably 10 minutes or more and 1 hour or less. When the time for the neutralization reaction is 10 minutes or longer, the neutralization reaction can sufficiently proceed. Moreover, since the working time can be shortened because the time of the neutralization reaction is 1 hour or less, it is industrially preferable.

  The reaction between epichlorohydrin and alkali metal (meth) acrylate is carried out in the presence of a catalyst. As the catalyst, a known catalyst can be used. For example, a quaternary ammonium salt can be used. As the quaternary ammonium salt, for example, tetraalkylammonium salts such as tetramethylammonium chloride, tetramethylammonium bromide, tetraethylammonium chloride, tetraethylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium bromide can be used. These may use only 1 type and may use 2 or more types together.

  In the reaction between epichlorohydrin and alkali metal (meth) acrylate and the neutralization reaction between (meth) acrylic acid and alkali metal hydroxide, a polymerization inhibitor may be used to suppress polymerization. it can. A known polymerization inhibitor can be used as the polymerization inhibitor. Examples of the polymerization inhibitor include phenols such as hydroquinone and paramethoxyphenol, and N-oxyls such as 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (HO-TEMPO). Can be used. These may use only 1 type and may use 2 or more types together. In order to prevent polymerization, it is preferable to bubble oxygen or air during the reaction.

  The reaction temperature in the reaction between epichlorohydrin and the alkali metal (meth) acrylate is preferably 70 ° C. or higher and 130 ° C. or lower, more preferably 80 ° C. or higher and 120 ° C. or lower. When the reaction temperature is 70 ° C. or higher, a sufficient reaction rate can be obtained. Moreover, the production | generation of a by-product can be suppressed because reaction temperature is 130 degrees C or less.

  The amount of the catalyst used in the reaction of epichlorohydrin and (meth) acrylic acid alkali metal salt is preferably 0.01 mol or more and 10 mol or less, based on 1 mol of (meth) acrylic acid alkali metal salt, 0.05 mol or more, 5 mol or less is more preferable. When the amount of the catalyst is 0.01 mol or more with respect to 1 mol of the alkali metal (meth) acrylate, a sufficient reaction rate can be obtained. Moreover, the production | generation of a by-product can be suppressed because the quantity of a catalyst is 10 mol or less with respect to 1 mol of (meth) acrylic-acid alkali metal salts.

  The amount of the polymerization inhibitor used in the reaction between epichlorohydrin and the alkali metal (meth) acrylate is preferably 10 ppm by mass or more and 10,000 ppm by mass or less based on the alkali metal (meth) acrylate. When the amount of the polymerization inhibitor is 10 ppm by mass or more, the polymerization can be sufficiently suppressed. Moreover, generation | occurrence | production of the quality fall by coloring etc. of a product can be suppressed because the quantity of a polymerization inhibitor is 10000 mass ppm or less.

  In the reaction of epichlorohydrin and alkali metal (meth) acrylate, it is known that the amount of by-products increases when the amount of water in the reaction solution at the time of raw material charging is large. However, there are also by-products in which the amount of production increases when the amount of water is small. In the present invention, the production of specific chlorine-containing impurities can be particularly suppressed by setting the water content of the reaction liquid at the time of raw material charging to the range of 2000 ppm to 10000 ppm by mass, and other by-products. Is also preferable because it can be relatively suppressed. The water content of the reaction solution at the time of raw material charging is more preferably 2500 ppm to 7000 ppm by mass, further preferably 3000 ppm to 5000 ppm, and particularly preferably 3500 ppm to 4500 ppm. In addition, the water content of the reaction liquid at the time of raw material preparation shows the water content contained in the reaction liquid which prepared all raw materials, such as epichlorohydrin, (meth) acrylic acid alkali metal salt, and a catalyst. Further, the water content of the reaction liquid at the time of raw material charging is a value analyzed by a Karl Fischer moisture meter.

  Examples of the chlorine-containing impurities whose generation is particularly suppressed include propenyl chloride (meth) acrylate represented by the following formula (1).

  In the formula (1), R represents hydrogen or a methyl group. Since the propenyl chloride (meth) acrylate represented by the formula (1) has a small boiling point difference from glycidyl (meth) acrylate, it cannot be separated by distillation and is mixed into the product. The present inventors have found that the amount of by-product of the propenyl chloride (meth) acrylate represented by the above formula (1) increases conversely in the region where the water content of the reaction solution at the time of charging the raw material is small. On the other hand, by setting the water content of the reaction solution at the time of charging the raw materials within the above range, the by-product amount of propenyl chloride (meth) acrylate represented by the formula (1) can be reduced, and the distillation distillation after distillation can be reduced. It was found that the amount of contamination in the effluent was reduced, and the total amount of chlorine in the distillate was reduced.

  The amount of water in the reaction solution at the time of raw material charging can be adjusted by adding pure water, ion-exchanged water or the like when increasing the amount of water. On the other hand, when reducing the amount of water, it can be adjusted by removing the water in the raw material epichlorohydrin or sodium methacrylate. Removal of water in epichlorohydrin can be performed using, for example, a molecular sieve. Moreover, the removal of the water | moisture content in sodium methacrylate can be performed, for example by drying under heating and reduced pressure.

[Washing process]
The method according to the present invention includes a step of washing the reaction solution obtained by the reaction of epichlorohydrin with an alkali metal (meth) acrylate at a temperature of -10 ° C or higher and lower than 20 ° C. In the reaction solution after completion of the reaction, there are alkali metal chloride, catalyst, surplus epichlorohydrin, by-product and the like in addition to glycidyl (meth) acrylate. By washing the reaction solution with washing water, the alkali metal chloride, catalyst and specific by-product can be dissolved in the aqueous layer and separated and removed.

  As washing water used for washing with water, water or an aqueous solution in which an alkaline compound is dissolved can be used. As the washing water, an aqueous solution in which an alkaline compound is dissolved is preferably used. By using an aqueous solution in which an alkaline compound is dissolved as the washing water, side reactions during the washing step can be further suppressed. Although it does not specifically limit as an alkaline compound, For example, an alkali metal hydroxide, an alkali metal carbonate, an alkali metal hydrogencarbonate etc. are mentioned. Specific examples include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate and the like. These may use only 1 type and may use 2 or more types together.

  The amount of the alkaline compound contained in the washing water is preferably 0 parts by mass or more and 20 parts by mass or less, more preferably 0.1 parts by mass or more and 10 parts by mass or less, with respect to 100 parts by mass of water constituting the washing water. 0.2 parts by mass or more and 3 parts by mass or less are more preferable. When the amount of the alkaline compound is within the above range, generation of by-products can be sufficiently suppressed.

  The amount of washing water used in the washing step is preferably an amount that can sufficiently dissolve the alkali metal chloride and the catalyst. Specifically, the amount of washing water is preferably 160 g or more and 300 g or less, more preferably 180 g or more and 250 g with respect to 1 mol of alkali metal hydroxide added in the neutralization of (meth) acrylic acid and alkali metal hydroxide. The following is more preferable. When the amount of the washing water is 160 g or more, the alkali metal chloride and the catalyst can be sufficiently dissolved. Moreover, productivity improves because the quantity of washing water is 300 g or less.

  The present inventors have found that the extraction efficiency of the by-product glycidol into the aqueous layer varies depending on the temperature of the reaction solution in the washing step. In the present invention, the reaction solution is washed with water at a temperature of −10 ° C. or more and less than 20 ° C. The temperature of the reaction solution is preferably -5 ° C or higher and 18 ° C or lower, more preferably -2 ° C or higher and 15 ° C or lower, and further preferably 0 ° C or higher and 15 ° C or lower. When the temperature of the reaction solution is −10 ° C. or higher, the cooling energy cost can be reduced. On the other hand, when the temperature of the reaction solution is 20 ° C. or lower, the extraction effect of glycidol into the aqueous layer is enhanced, and glycidol can be sufficiently removed. In addition, since salt and impurities dissolve in the water layer, there is a region that does not freeze at 0 ° C. or lower.

  After setting the temperature of the reaction solution within the range of −10 ° C. or more and less than 20 ° C., washing water is added to the reaction solution, and the temperature of the mixture solution is controlled within the range of −10 ° C. or more and less than 20 ° C. during mixing. If the temperature of the liquid mixture is within an appropriate range, the process may be performed without particularly controlling the temperature. Further, the reaction liquid may be cooled, washing water may be added to the reaction liquid, and the temperature of the liquid mixture may be controlled within a range of −10 ° C. or more and less than 20 ° C. during mixing. As long as the temperature is within the range, the process may be performed without particularly controlling the temperature. The temperature of the reaction solution may or may not be constant during mixing as long as it is within a range of −10 ° C. or more and less than 20 ° C.

  A known stirring method can be used for washing with water. 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 can be, for example, 3 minutes or more and 60 minutes or less.

  The reaction solution and the washing water are stirred and mixed, and then allowed to stand to separate into a washing organic layer and an aqueous layer. The washed organic layer can be purified in the next distillation step.

[Distillation process]
The method according to the present invention may comprise the step of distilling the washed organic layer. By distilling the washed organic layer, glycidyl (meth) acrylate can be obtained. The washing organic layer can be distilled by a known method. In order to obtain high-purity glycidyl (meth) acrylate, it is preferable to perform rectification using a column. Distillation can be carried out either batchwise or continuously, but the batch-type precision distillation will be described below.

  Since glycidyl (meth) acrylate is a polymerizable monomer, polymerization can be suppressed by performing distillation at a lower temperature under reduced pressure. From the above viewpoint, the temperature of the distillation pot is preferably 160 ° C. or less, and more preferably 150 ° C. or less. 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, the degree of reduced pressure is preferably 0.1 kPa or more, more preferably 0.5 kPa or more, from the viewpoint of the reduced pressure limit. On the other hand, from the viewpoint of lowering the temperature, 50 kPa or less is preferable, and 30 kPa or less is more preferable.

  In order to suppress the polymerization, a known polymerization inhibitor can be fed into the distillation kettle and the column. As the polymerization inhibitor, for example, phenols such as hydroquinone and paramethoxyphenol, and N-oxyls such as 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (HO-TEMPO) are used. can do. These may use only 1 type and may use 2 or more types together. In order to prevent polymerization, it is preferable to bubble oxygen or air during distillation.

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

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these. Gas chromatography (GC) analysis was used for quantification of each compound in Examples and Comparative Examples.

  The total chlorine content (ppm) in the distilled distillate is combusted by raising the temperature of the distillate distillate to 100 to 900 ° C. using a sample combustion apparatus QF-02 (trade name, manufactured by Mitsubishi Chemical Corporation), After the gas was absorbed by the absorption tube, it was quantified by analyzing by IC (ion chromatography).

Example 1
As a polymerization inhibitor, 0.04 g of benzoyl ester of HO-TEMPO was dissolved in 387.4 g (4.5 mol) of methacrylic acid. This solution was mixed with an aqueous solution in which 180 g (4.5 mol) of sodium hydroxide was dissolved in 420 g of water. This mixed solution was spray-dried with 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. In the flask, 221.8 g (2.05 mol) of sodium methacrylate, 0.925 g (0.008 mol) of trimethylammonium chloride as a catalyst, 0.023 g of benzoyl ester of HO-TEMPO as a polymerization inhibitor, and 990 g (10.7 mol) of epichlorohydrin was added. It was 4460 mass ppm when the moisture content of the reaction liquid at the time of raw material preparation was analyzed with the Karl Fischer method using the moisture meter by Mitsubishi Chemical Corporation (brand name: CA-21). While introducing air at 10 ml / min into the flask, the reaction solution was heated to 90 ° C. in an oil bath while stirring the reaction solution. Heating was continued for 2 hours after the temperature of the reaction solution reached 90 ° C., so that the temperature of the reaction solution became 89 to 91 ° C. Thereafter, the reaction solution was cooled to 10 ° C. While controlling the temperature of the reaction solution at 10 ° C., 440 g of a 0.57 mass% sodium hydroxide aqueous solution was mixed to wash the reaction solution. GC analysis of the washed organic layer at this time revealed that the area percentage of propenyl methacrylate chloride (CPMA) was 0.058% (vs. glycidyl methacrylate (GMA), the same applies hereinafter), and the area percentage of glycidol was 0.458%. .

  Similarly, a reaction step and a water washing step were separately performed. The 2142 g of the washed organic layer of 2 batches obtained as described above was charged into a flask equipped with an old show with a five-stage tray and subjected to precision distillation. After distilling and collecting excess epichlorohydrin, the main distillate was distilled under the conditions of an internal temperature of 94 to 126 ° C., a tower top temperature of 69 to 82 ° C., a pressure of 1.33 to 2.40 kPa, and a reflux ratio of 1. It was. As a result, 402 g of glycidyl methacrylate was obtained. The area percentage of CPMA in the distillate was 0.057%, and the area percentage of glycidol was 0.063%. Moreover, it was 388 mass ppm when the total chlorine amount in a distillate was analyzed. The results are shown in Table 1.

(Examples 2 to 4 and Comparative Examples 1 to 7)
The reaction step, the water washing step and the distillation step were carried out in the same manner as in Example 1 except that the water content of the reaction solution at the time of charging the raw material in the reaction step and the temperature of the reaction solution in the water washing step were changed to the values shown in Tables 1 and 2. And conducted various analyses. The results are shown in Tables 1 and 2. The amount of water in the reaction solution at the time of raw material charging was adjusted by adding pure water when the amount of water was increased. On the other hand, when reducing the amount of water, it was adjusted by removing the water in the raw material epichlorohydrin or sodium methacrylate. Removal of water in epichlorohydrin was performed using molecular sieves. Moreover, the water | moisture content in sodium methacrylate was removed by drying under heating and reduced pressure.

  The glycidyl (meth) acrylate produced by the method according to the present invention can be used for various paints, adhesives, pressure-sensitive adhesives, various reactive monomers, and the like.

Claims (2)

A step of reacting epichlorohydrin with an alkali metal (meth) acrylate in the presence of a catalyst;
And a step of washing the reaction solution obtained by the reaction with water at a temperature of −10 ° C. or higher and lower than 20 ° C., and a method for producing glycidyl (meth) acrylate.   The water content of the reaction liquid at the time of raw material preparation is 2000 mass ppm or more and 10000 mass ppm or less in the step of reacting epichlorohydrin and (meth) acrylic acid alkali metal salt in the presence of a catalyst. A method for producing glycidyl (meth) acrylate.