JPH1180087A - Production of high-purity lower alkyl ester of pyruvic acid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce the subject compound useful as a raw material for medicines and agrochemicals, cleaning agents for producing electronic materials or the like in high yield by distilling and purifying a lower alkyl ester of pyruvic acid in the presence of an epoxy group-containing compound and a quaternary ammonium group-containing compound. SOLUTION: When a lower alkyl ester of pyruvic acid (e.g. methyl pyruvate) is distilled and purified, a compound having epoxy group (e.g. a bisphenol A type epoxy compound) and a compound having a quaternary ammonium group (e.g. triethylbenzylammonium chloride) and having a higher boiling point than that of the lower alkyl ester of the pyruvic acid under atmospheric pressure in respective weights of 0.001-0.2 based on the lower alkyl ester of the pyruvic acid are subjected to the distillation and purification thereof. Thereby, the objective high-purity lower alkyl ester of the pyruvic acid, useful as a raw material for producing medicines and agrochemicals and cleaning agents or the like for producing electronic materials without containing chloride ions is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION [0002] Lower alkyl pyruvate is used as a raw material for the production of pharmaceuticals and agricultural chemicals, as a detergent for the production of electronic materials, etc., all of which are applications that are reluctant to contain impurities. In particular, when it is used as a cleaning agent for producing electronic materials, it is necessary to keep the chlorine ion content at a low level. In the case of producing pyruvic acid lower alkyl ester, distillation purification is a simple and efficient method for purifying the product.However, distillation equipment is generally made of metal having a complicated structure, and chlorine ion is used. Susceptible to corrosion by. Therefore, in order to prevent corrosion at the time of distillation purification and obtain a high-quality lower alkyl pyruvate, a technique for reducing chloride ions in the process and in the product is required.

[0002]

2. Description of the Related Art As a method for producing an alkyl pyruvate, a method of dehydrogenating or oxidizing a lactic acid ester (JP-B-57-24336, JP-A-1-242554, etc.) and a method of ozone-oxidizing a methacrylate ester (EP-147593, JP-A-55-62040), a method of esterifying pyruvic acid with an alcohol (J. Am. Chem. Soc., 66, 1656 (1)
944) and Japanese Patent Application No. 8-218864), but no technique for reducing or removing chloride ions has been proposed. In particular, when thionyl chloride is used in the esterification reaction, or in a process in which the lower alkyl pyruvate is extracted with a chlorinated solvent, there is a high possibility that chloride ions will be mixed in the process or in the product. Alkaline metal carbonates such as potassium hydrogen, potassium carbonate, sodium hydrogen carbonate, and sodium carbonate are added for purification by distillation. However, the pyruvic acid lower alkyl ester was decomposed by the alkali metal carbonate, and the chloride ions in the distilled and purified pyruvic acid lower alkyl ester could not be reduced, or no satisfactory results were obtained.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to reduce chloride ions in the process for producing lower alkyl pyruvate, particularly in the distillation process and in the lower alkyl pyruvate.

[0004]

Means for Solving the Problems In order to solve the problems, the present inventors have conducted intensive studies with the aim of reacting chloride ions with an epoxy compound to convert them into chlorohydrin, which is an organic compound having a higher boiling point than pyruvate lower alkyl ester.
It has been found that the present invention can be implemented efficiently, and the present invention has been reached. That is, a compound having an epoxy group and a compound having a quaternary ammonium group are added to a distillation raw material of a lower alkyl ester of pyruvic acid, and the mixture is purified by distillation to obtain a chloride ion content of 1
This is a method for producing a high-purity pyruvate lower alkyl ester to produce a high-purity pyruvate lower alkyl ester of 0 ppm or less.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a method for purifying a distillate by adding an epoxy compound having an epoxy group and a compound having a quaternary ammonium group to a raw material to be supplied to distillation which is carried out as a final step of the production of a lower alkyl pyruvate. The goal can be achieved. The compound having a quaternary ammonium group here is a catalyst for the reaction between the chloride ion and the epoxy compound.

The distillation material used in the present invention has 1 to 1 carbon atoms.
Those esterified or transesterified with the alkyl group of No. 4 are preferred, and specific examples include pyruvate methyl ester, pyruvate ethyl ester, pyruvate propyl ester, and pyruvate butyl ester. Chemical synthesis methods that contain chloride ions, or that contain organic chlorides and may generate chloride ions by decomposition, or lower alkyl esters of pyruvate produced from pyruvate in fermentation methods, etc. Can be preferably adopted when using as a raw material.

The compound having an epoxy group and the compound having a quaternary ammonium group used in the present invention may be a reaction product of a chloride ion and an epoxy compound, an unreacted epoxy compound, or a compound having a quaternary ammonium group. Since it is necessary to separate the pyruvic acid lower alkyl ester as a high boiling point product by distillation, the boiling point is higher than the pyruvic acid lower alkyl ester, and the boiling point at normal pressure is preferably 10 ° C. or higher than the boiling point of the pyruvic acid lower alkyl ester. Are preferred. Although there is no particular limitation, the compound having an epoxy group is a reaction product of epichlorohydrin and phenol or bisphenol A, and preferably has a low molecular weight epoxy equivalent of 200 g /
Those having an equivalent weight or less are preferred. The amount of addition should be 1 equivalent times the amount of chloride ions. However, the decomposition of chlorine ions may occur after containing organic chlorides. It is preferably 0.001 to 0.2 times by weight, more preferably 0.001 to 0.1 times by weight based on the ester distillation material.
Weight times.

Compounds having a quaternary ammonium group include aliphatic quaternary ammonium salts such as tetramethylammonium chloride, cetyltrimethylammonium chloride, stearyltrimethylammonium chloride, distearyldimethylammonium chloride, trimethylbenzylammonium chloride, and the like. Aromatic quaternary ammonium salts such as triethylbenzylammonium, triethylbenzylammonium bromide, lauryldimethylbenzylammonium chloride and myristyldimethylbenzylammonium chloride; and heterocyclic quaternary ammonium salts such as N-laurylpyridinium chloride and cetylpyridinium chloride. Can be The amount of addition is 0.1 to the compound having epoxy group.
It is preferably 001 to 0.2 times by weight, more preferably 0.001 to 0.1 times by weight.

[0009] A predetermined amount of an epoxy compound having an epoxy group and a compound having a quaternary ammonium group are added to a raw material in which chloride ions may be generated by decomposition of an organic chloride, and the resulting mixture is stored immediately before use. It can be purified by distillation.

The distillation purification used in the present invention is carried out under normal pressure to 4 kPa using a rectification column having a distillation temperature of 40 to 100 ° C., but not particularly limited thereto, and having an effective number of 10 or more stages. Is preferred. The material of the rectification device including the filler may be either glass or stainless steel.

[0011]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. still,
The concentration analysis of pyruvic acid and lower alkyl pyruvate was carried out by gas chromatogram. Further, the chloride ion concentration analysis was performed by an automatic titrator using an N / 100 silver nitrate aqueous solution.

Example 1 In a 300 ml three-necked flask equipped with a thermometer, a condenser, a Dean Stark, a dropping funnel, and a stirrer, 110 g of an aqueous pyruvate solution having a water concentration of 13% obtained from a fermentation broth containing pyruvic acid (pyruvin) Acid 1.0 mol) and 1
102.3 g of 0% aqueous ethanol (2.0 mol of ethanol) was added, and the mixture was heated at 80 ° C. for 3 hours. Then, while adding 55 g of cyclohexane from the dropping funnel into the flask, at normal pressure, water and ethanol in the flask were evaporated together with cyclohexane at 80 ° C., and at the same time, the distillate vapor was cooled with a condenser, and then Dean-Stark. The operation of separating the layers and returning only the separated cyclohexane layer to the heating system was repeated until substantially no aqueous layer appeared, and then cyclohexane was distilled off at 80 ° C. under normal pressure to 17.3 kPa. The reaction liquid remaining in the flask was cooled, and the concentration of pyruvic acid in the liquid was analyzed. As a result, the residual ratio of pyruvic acid to the charged pyruvic acid was 40%.

[0013] To the reaction solution, 20.3 g of 1.1 mol of ethanol based on pyruvic acid remaining in the reaction solution is added,
Then, at a temperature of 30 to 70 ° C., 50.0 g of thionyl chloride (1.05 mol) is added to pyruvic acid remaining in the reaction solution, and the generated hydrogen chloride and sulfur dioxide are reduced to normal pressure.
It was taken out of the reaction system at 3 kPa and absorbed in an aqueous alkali solution.

After the reaction, a bisphenol A type epoxy compound (trade name: YD-12, manufactured by Toto Kasei Co., Ltd.)
8) 1.5 g and 0.15 g of triethylbenzylammonium chloride quaternary ammonium salt were added, and the mixture was stirred well at a temperature of 70 ° C. for 1 hour, and then distilled under a normal pressure of 80 ° C. and 4 kPa. As a result of analyzing the concentration of pyruvic acid ethyl ester in the distillate, ethyl pyruvic acid ester could be recovered in 93% yield with respect to the charged pyruvic acid. Also,
The chloride ion concentration in the distilled ethyl pyruvate was 10 ppm or less, which is the detection limit.

Example 2 In a 300 ml three-necked flask equipped with a thermometer, a condenser, a Dean Stark, a dropping funnel, and a stirrer, 110 g of a 13% aqueous solution of pyruvic acid obtained from a fermentation culture solution containing pyruvic acid (pyruvin) Acid 1.0 mol) and 1
133.6 g (2.0 mol of 2-propanol) containing 0% aqueous 2-propanol was added, and the mixture was heated at 85 ° C. for 5 hours.

Then, while adding 55 g of cyclohexane from the dropping funnel into the flask, the water and 2-propanol in the flask are evaporated together with cyclohexane at 85 ° C. under normal pressure at 85 ° C., and simultaneously the distillate vapor is cooled by a condenser. Then, the operation of separating the layers by Dean Stark and returning only the separated cyclohexane layer to the heating system was repeated until substantially no aqueous layer appeared.
Cyclohexane was distilled off under 3 kPa. The reaction liquid remaining in the flask was cooled, and the concentration of pyruvic acid in the liquid was analyzed. As a result, the residual ratio of pyruvic acid to the charged pyruvic acid was 41%. The reaction solution contained 1.1 mol of 2-propanol 2 with respect to pyruvic acid remaining in the reaction solution.
7.1 g was added, and then at a temperature of 30 to 70 ° C., 51.2 g of 1.05 mol of thionyl chloride based on pyruvic acid remaining in the reaction solution was added. The solution was taken out of the reaction system at 0.3 kPa and absorbed in an aqueous alkaline solution.

After the reaction, a bisphenol A type epoxy compound (trade name: YD-12, manufactured by Toto Kasei Co., Ltd.)
8) 1.5 g and 0.15 g of triethylbenzylammonium chloride quaternary ammonium salt were added, and the mixture was stirred well at a temperature of 70 ° C. for 1 hour, and then distilled under a normal pressure of 80 ° C. and 4 kPa. As a result of analyzing the concentration of pyruvic acid 2-propyl ester in the distillate, pyruvic acid 2-propyl ester was able to be recovered in 93% yield with respect to the charged pyruvic acid. The chloride ion concentration in the distilled 2-propyl ester of pyruvic acid was 10 ppm or less, which is the detection limit.

Example 3 Instead of the bisphenol A type epoxy compound of Example 1 (trade name: YD-128, manufactured by Toto Kasei Co., Ltd.), a phenylglycidyl ether compound (manufactured by Sanko Chemical Co., Ltd.) The same operation as in Example 1 was carried out except that 1.5 g of OPP-G) was added. As a result, the distilled ethyl pyruvate was obtained in a yield of 93 with respect to the charged pyruvic acid.
%. The chloride ion concentration in the distilled ethyl pyruvate was below the detection limit of 10 ppm.

Example 4 Stearyl dimethylbenzyl ammonium chloride (manufactured by Sanyo Chemical Industries, Ltd., trade name) instead of the quaternary ammonium salt of triethylbenzylammonium chloride of Example 1
The same operation as in Example 1 was performed except that 0.20 g of (cation SK, main component composition: about 86%) was added. As a result, the distilled ethyl pyruvate was obtained in a yield of 93% based on the charged pyruvic acid. Collected. The chloride ion concentration in the distilled pyruvic acid ethyl ester is less than the detection limit of 10 p.
pm or less.

Comparative Example 1 Bisphenol A type epoxy compound of Example 1 (trade name: YD-128, manufactured by Toto Kasei KK) and 50% potassium carbonate instead of the quaternary ammonium salt of triethylbenzylammonium chloride The same operation as in Example 1 was carried out except that 1.5 g of an aqueous solution was added. As a result, the distilled ethyl pyruvate could be recovered at a yield of 90% with respect to the charged pyruvic acid. The chloride ion concentration in the distilled ethyl pyruvate was 25 ppm.

Comparative Example 2 Bisphenol A type epoxy compound (trade name: YD-128, manufactured by Toto Kasei Co., Ltd.) of Example 2 and 50% potassium carbonate instead of quaternary ammonium salt of triethylbenzylammonium chloride As a result of performing the same operation as in Example 2 except that 1.5 g of an aqueous solution was added, distilled 2-propyl ester of pyruvic acid could be recovered with a yield of 91% based on the charged pyruvic acid. Further, the chloride ion concentration in the distilled pyruvic acid 2-propyl ester is 30
ppm.

[0022]

According to the present invention, an epoxy compound having an epoxy group and a compound having a quaternary ammonium group are added to pyruvate ethyl ester containing chloride ions,
By purifying by distillation, a high-purity pyruvate lower alkyl ester containing no chloride ion can be provided, which can greatly contribute to quality improvement of the pyruvate lower alkyl ester.

Claims (8)

[Claims] 1. A method for producing a high-purity pyruvate lower alkyl ester, comprising purifying a lower alkyl pyruvate by distillation in the presence of a compound having an epoxy group and a compound having a quaternary ammonium group. . 2. The pyruvic acid lower alkyl ester is pyruvic acid methyl ester, pyruvic acid ethyl ester,
2. The method for producing a high-purity lower alkyl pyruvate according to claim 1, wherein the ester is at least one selected from propyl pyruvate and butyl pyruvate. 3. The high-purity pyrvin according to claim 1, wherein the compound having an epoxy group and the compound having a quaternary ammonium group have a boiling point at normal pressure which is higher than the boiling point of the lower alkyl ester of pyruvate. A method for producing an acid lower alkyl ester. 4. The high-purity pyruvic acid according to claim 1, wherein the compound having an epoxy group is added in an amount of 0.001 to 0.2 times by weight of the lower alkyl pyruvate. Method for producing lower alkyl ester. 5. The high-purity compound according to claim 1, wherein the compound having a quaternary ammonium group is added in an amount of 0.001 to 0.2 times the weight of the compound having an epoxy group. A method for producing a lower alkyl pyruvate. 6. The method for producing a high-purity pyruvate lower alkyl ester according to claim 1, wherein the distillation temperature is 40 to 100 ° C. 7. A high-purity pyruvic acid lower alkyl ester having a chlorine ion content of 10 ppm or less. 8. A low-purity pyruvic acid lower alkyl ester having a chlorine ion content of 10 ppm or less, which is distilled by the method according to claim 1.