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Method for improving purity of chloroacetaldehyde dimethyl acetal by vinyl acetate method

A vinyl acetate-method chloroacetal dimethyl acetal and chloroacetal dimethyl acetal technology are applied in chemical instruments and methods, preparation of organic compounds, compounds of Group 5/15 elements of the periodic table, etc. Difficult to separate, difficult to meet medical requirements, low quality of chloroacetal dimethyl acetal, etc., to achieve the effect of high efficiency and easy operation

Pending Publication Date: 2020-12-01
石家庄欧特佳化工有限公司
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  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the boiling point of methyl chloroacetate is 129.5°C, which is very close to the boiling point of 127.5°C of chloroacetaldehyde dimethyl acetal, it is difficult to separate, resulting in the low quality of the produced chloroacetaldehyde dimethyl acetal, which is difficult to meet the requirements of the pharmaceutical industry

Method used

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  • Method for improving purity of chloroacetaldehyde dimethyl acetal by vinyl acetate method

Examples

Experimental program
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Effect test

Embodiment 1

[0017] 1. Add 8 kg of chloroacetaldehyde dimethyl acetal containing 2.2% methyl chloroacetate (equivalent to 176g / 108.52=1.62mol), 1Kg of triphenyl Phosphine (3.81mol), heated to 80°C with stirring until the methyl chloroacetate content was lower than 0.1%, and the reaction time was about 8 hours.

[0018] 2. Change the reaction device into a vacuum distillation device, and distill about 7Kg of chloroacetaldehyde dimethyl acetal under the conditions of 0.095Mpa and 70°C, with a gas phase purity of 99.6%. The remaining liquid was naturally cooled to room temperature, and the white solid generated by suction filtration under reduced pressure was rinsed with 500 g of chloroacetaldehyde dimethyl acetal containing 2.2% methyl chloroacetate, and dried naturally to obtain 561 g of quaternary phosphorus salt (FW370.81). 152-153°C.

Embodiment 2

[0020] In the above-mentioned embodiment one, filter the filtrate of the quaternary phosphorus salt, add 7.5Kg of chloroacetaldehyde dimethyl acetal containing 2.2% methyl chloroacetate, 550g triphenylphosphine, repeat the operation of the first and second steps of the above-mentioned embodiment one , 7.8Kg of chloroacetaldehyde dimethyl acetal with a purity of 99.6%, 570g of quaternary phosphorus salt, and a melting point of 152-153°C can be obtained.

Embodiment 3

[0022] 1. Add 742g of the quaternary phosphorus salt obtained in the above-mentioned Example 1 into a 5L three-necked bottle with a mechanical stirrer, a thermometer, and a dropping funnel, add 2L of water and 200g of methanol to dissolve, control the temperature at 5-10°C, and add 10% dropwise NaOH solution 820g.

[0023] 2. Filtrate the resulting white solid, rinse with 100mL distilled water, and dry naturally to obtain 650g of methoxyformylmethylene triphenylphosphine, with a yield of 97%, melting point: 170-172°C, and a liquid chromatography purity of 98.5% .

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Abstract

The invention discloses a method for improving the purity of chloroacetaldehyde dimethyl acetal by a vinyl acetate method. The method has the principle that triphenylphosphine and methyl chloroacetateare easily subjected to nucleophilic substitution reaction to convert quaternary phosphonium salt and filter and remove the quaternary phosphonium salt, thereby improving the purity of chloroacetaldehyde dimethyl acetal. According to the method, the activity difference of nucleophilic substitution reaction between triphenylphosphine and methyl chloroacetate is skillfully utilized, and triphenylphosphine which is more than methyl chloroacetate is added into a methyl chloroacetate-containing chloroacetaldehyde dimethyl acetal crude product so that the triphenylphosphine and the methyl chloroacetate are subjected to nucleophilic substitution reaction to generate a non-volatile quaternary phosphonium salt solid; then reduced pressure distillation is performed to obtain chloroacetaldehyde dimethyl acetal with higher purity; cooling and filtering are performed kettle residues to recover quaternary phosphonium salt for synthesizing a Wittig reagent, namely methoxyformyl methylene triphenylphosphine, wherein excessive triphenylphosphine in mother liquor can be repeatedly used; the method is free of expensive reagents, easy and convenient to operate, high in benefit and easy to industrialize.

Description

technical field [0001] The invention relates to the technical field of organic chemistry, in particular to a method for improving the purity of chloroacetaldehyde dimethyl acetal by vinyl acetate method. Background technique [0002] Currently, chloroacetaldehyde dimethyl acetal produced by vinyl acetate method will contain 23% methyl chloroacetate. Since the boiling point of methyl chloroacetate is 129.5°C, which is very close to the boiling point of 127.5°C of chloroacetaldehyde dimethyl acetal, it is difficult to separate, resulting in the low quality of the produced chloroacetaldehyde dimethyl acetal, which is difficult to meet the requirements of the pharmaceutical industry. Contents of the invention [0003] The object of the present invention is to provide a kind of method that improves vinyl acetate method chloroacetaldehyde dimethyl acetal purity, to solve the problem that proposes in the above-mentioned background technology. [0004] In order to achieve the abo...

Claims

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Application Information

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IPC IPC(8): C07C41/58C07C43/313C07F9/54C07F9/50
CPCC07C41/58C07F9/5442C07F9/5022C07C43/313
Inventor 张文勤曹立军许江涛
Owner 石家庄欧特佳化工有限公司
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