JPH0120152B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a glycidyl ester of acrylic acid or methacrylic acid by reacting an alkali metal salt of acrylic acid or methacrylic acid with epihalohydrin. To provide a method by which an aqueous layer and an organic layer can be easily separated without emulsification when washed with water.

Acrylic acid or methacrylic acid (hereinafter collectively referred to as (meth)acrylic acid) in epichlorohydrin. ]
and an alkali metal carbonate or bicarbonate to form an alkali metal salt of the acid, a catalyst is then added to the reaction system, and the alkali metal salt is reacted with epichlorohydrin to form a (meth)acrylic acid. A method for producing glycidyl esters of acids has already been disclosed in GB 1460703. In this method, after the completion of the reaction, inorganic compounds such as unreacted alkali metal carbonate and bicarbonate and the reaction product alkali metal chloride are removed from the reaction product solution by filtration. Subjecting the liquid to distillation to achieve the desired purpose (meth)
Glycidyl ester of acrylic acid is obtained. In this case, organic compounds such as glycidol, glycerin, and glycerin-α-monochlorohydrin, which are by-produced in the above reaction, remain in the reaction product solution after the reaction and are not sufficiently removed even by distillation. A decrease in the purity of the glycidyl ester is unavoidable.

Furthermore, the catalyst (quaternary ammonium salt) remains in the reaction product solution after the reaction, which promotes polymerization of the glycidyl ester during distillation and causes a decrease in the yield of the desired glycidyl ester (for example, (See Publication No. 53-23817).

On the other hand, it is also possible to wash the reaction product of the alkali metal salt of (meth)acrylic acid and epichlorohydrin with water, but if water is added to this reaction solution, it becomes an emulsified state and the aqueous layer and organic layer cannot be separated. This not only makes it difficult to handle the reaction product solution, but also causes a decrease in product yield and product purity (see, for example, Japanese Patent Publication No. 45-28762).

The present invention is intended to overcome the deficiencies of the above-mentioned conventional methods, and its purpose is to react (meth)acrylic acid with an alkali metal carbonate and/or bicarbonate in epihalohydrin. to produce an alkali metal salt of the acid, then add a catalyst to this reaction system, and react the alkali metal salt with epihalohydrin (meth).
In a method for producing glycidyl ester of acrylic acid, the objective is to provide a method for removing impurities by washing the obtained reaction product liquid with water, and to produce glycidyl ester of (meth)acrylic acid with high purity in a high yield. It makes it possible to manufacture. More specifically, the object of the present invention is achieved by easily separating an organic layer and an aqueous layer without emulsification when water is added to the reaction product liquid and washed with water. be.

Emulsification during water washing of the reaction product liquid is suitably suppressed by allowing the reaction to proceed while blowing air into the reaction system, and the present invention provides
In detail, it is performed as follows. That is, (1)
An equivalent or more amount of alkali metal carbonate and/or bicarbonate relative to (meth)acrylic acid is suspended in an excess amount of epihalohydrin, and (meth)acrylic acid is added to this suspension heated to the desired temperature. (Meth)acrylic acid is produced by reacting (meth)acrylic acid with the above carbonates under conditions in which acid is gradually added and water produced by neutralization is azeotropically distilled with epihalohydrin and distilled out of the reaction system. During the neutralization reaction to form an alkali metal salt of (meth)acrylic acid, and by adding a catalyst to the reaction system after neutralization, the alkali metal salt of (meth)acrylic acid and epihalohydrin are reacted to form glycidyl ester of (meth)acrylic acid. (2) After the completion of the reaction, water is added to the reaction product solution, washed with water by stirring, and the aqueous layer to be separated is removed. The method of the present invention is implemented by subjecting the obtained organic layer to distillation, thereby obtaining a high yield and high purity glycidyl ester of (meth)acrylic acid.

Alkali metal carbonates and bicarbonates used in the present invention include sodium carbonate, sodium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate, etc., and are used in an amount equivalent to or more than the amount of (meth)acrylic acid. Usually, it is preferable to select it in the range of 1.1 to 1.7 equivalents.

As the epihalohydrin, epichlorohydrin is preferred for the purposes of the present invention, but epipromhydrin, β-methylepichlorohydrin, etc. may also be used. The amount of epihalohydrin used is preferably selected such that at least 5 times the mole of (meth)acrylic acid is present in the system during the neutralization reaction and the esterification reaction.

Catalysts added during the esterification reaction include:
Known quaternary ammonium salts such as trimethylbenzylammonium chloride, triethylbenzylammonium chloride, tetramethylammonium chloride, and tetramethylammonium bromide may be used. The amount of catalyst used is the amount normally used in this type of reaction, i.e. relative to (meth)acrylic acid.
It is selected in an amount of about 0.01 to 1.5 mol%.

The reaction temperature in the neutralization reaction needs to be high enough to azeotropically distill off the water produced by the neutralization together with the epihalohydrin. It is also possible to lower the azeotropic temperature by reducing the pressure of the reaction system. Adding (meth)acrylic acid under these temperature conditions,
If (meth)acrylic acid is added all at once or rapidly, a rapid neutralization reaction will occur, making it difficult to stir sufficiently or causing side reactions, so do not add (meth)acrylic acid. It is preferable to do it gradually. As (meth)acrylic acid is added, water is distilled out azeotropically along with epihalohydrin, but epihalohydrin may be separated and returned to the reaction system. After adding (meth)acrylic acid, the reaction is continued until water is completely distilled off azeotropically.

Once neutralization is complete, add the catalyst mentioned above and heat to 90-120°C.
The esterification reaction between the alkali metal salt of (meth)acrylic acid and epihalohydrin is carried out over a period of 1 to 3 hours.

In carrying out the present method of the present invention, it is preferable that a polymerization inhibitor be present during the neutralization reaction and the esterification reaction. The polymerization inhibitor may be selected from among polymerization inhibitors.

After the reaction is completed, in order to isolate the desired glycidyl ester of (meth)acrylic acid from the reaction mixture, in addition to the generated alkali halide and unreacted alkali metal salt, water-soluble by-product organic compounds such as glycidol and The catalyst is transferred to the aqueous layer and removed, and excess epihalohydrin is distilled off from the resulting organic layer under reduced pressure to obtain the desired glycidyl ester of (meth)acrylic acid.

Next, the method of the present invention will be explained using examples.

Example 1 A four-necked flask with a capacity of 1 was charged with 655.0 g of epichlorohydrin, 90.1 g of anhydrous sodium carbonate, and 1.0 g of hydroquinone monomethyl ether.
The flask was immersed in an oil bath maintained at 125°C. While blowing air into the reaction solution at a rate of 15 to 20 ml/min,
Methacrylic acid 86.1 when the internal temperature reaches 106℃
g was added dropwise over 50 minutes. After the dropwise addition was started, epichlorohydrin and water that were azeotropically distilled out were distilled out of the system. Approximately 30 minutes after the completion of dripping, the internal temperature will drop to
The temperature rose to 116.5°C, and azeotropic distillation almost disappeared. The azeotropic distillate obtained at this time had an epichlorohydrin layer of 116.7 g and an aqueous layer of 5.1 g. Next, while continuously blowing air into the reaction solution at a rate of 15 to 20 ml/min, 0.40 g of triethylbenzylammonium chloride as a catalyst was added, and the reaction was allowed to proceed for 2 hours.

After the reaction was completed, air blowing was stopped, the mixture was cooled to 25° C., 250 g of water was added, and the mixture was stirred for 40 seconds.
After standing still for 1 hour, the oil layer and water layer were separated. No emulsified state due to mixing with water was observed, and the oil layer and water layer could be easily separated. When the oil layer was analyzed by gas chromatography, it was found that glycidyl methacrylate was obtained corresponding to 90.6% of the theoretical yield, and the amount of glycidol contained in the oil layer was 0.69% based on the glycidyl methacrylate.

Example 2 60.0 kg of epichlorohydrin, 8.25 kg of anhydrous sodium carbonate, and 0.09 kg of hydroquinone monomethyl ether were charged into a 100 mm stainless steel reaction tank. The reaction mixture was heated while blowing air at a rate of 1.27/min, and when the internal temperature reached 103°C, 7.89 kg of methacrylic acid was added over 50 minutes. Epichlorohydrin and water, which azeotropically distilled out shortly after the addition started, were distilled out of the system. Approximately 30 minutes after the addition was completed, the internal temperature rose to 116°C, and almost no azeotropic distillation occurred. The azeotropic distillate obtained at this time had an epichlorohydrin layer of 13.84 kg and an aqueous layer of 0.60 kg. Next, 0.04 kg of triethylbenzylammonium chloride as a catalyst was added while continuously blowing air into the reaction solution at a rate of 1.27/min, and the reaction was allowed to proceed at the same temperature for 2 hours.

After the reaction was completed, air blowing was stopped, the mixture was cooled to 25°C, 22.90 kg of water was added, and the mixture was stirred for 1 minute and 30 seconds. After standing, the oil layer and water layer were easily separated, and no emulsification caused by mixing with water was observed.

When the oil layer was analyzed using a gas chromatograph,
Glycidyl methacrylate corresponding to a theoretical yield of 91.4% was obtained, and the amount of glycidol by-product contained in the oil layer was smaller than that of glycidyl methacrylate.
It was found to be 0.58%.

Comparative Example 1 The same raw materials were used in the same amounts as in Example 1, and the reaction was carried out under the same conditions, except that the reaction was carried out without blowing air during the reaction.

After the reaction was completed, the mixture was cooled to 25° C. and then 250 g of water was added and stirred for 40 seconds. Emulsification occurred, and complete separation of the oil and water layers was not observed even after being left to stand for more than 2 hours.

Comparative Example 2 In Example 1, instead of adding water after the reaction and stirring to transfer the inorganic substances to the aqueous layer and remove them,
The inorganic matter was removed by filtration, the residue was washed with epichlorohydrin, and the solution was combined with the above solution and analyzed by gas chromatography, and it was found that by-product glycidol was contained in an amount of 1.53% based on glycidyl methacrylate.

Claims (1)

[Claims] 1 Reacting acrylic acid or methacrylic acid with an alkali metal carbonate and/or bicarbonate in an excess amount of epihalohydrin to form an alkali metal salt of acrylic acid or methacrylic acid, and then adding a catalyst to the reaction system. In the method for producing glycidyl ester of acrylic acid or methacrylic acid by reacting the alkali metal salt with epihalohydrin, air is blown into the reaction solution during the above reaction, and water is added to the reaction product solution after the reaction is completed. 1. A method for producing glycidyl ester of acrylic acid or methacrylic acid, which comprises adding the glycidyl ester, separating an aqueous layer and an organic layer, and distilling the organic layer.