Method for synthesizing p-toluenesulfonic acid-catalyzed dimethyl malonate

A technology of dimethyl malonate and p-toluenesulfonic acid, which is applied in the field of malonate preparation, can solve the problems of easy decomposition of cyanoacetic acid and consumption of sulfuric acid acid waste water, etc., so as to reduce the amount of use, reduce the amount of use and the amount of waste water generated , avoid the effect of high salt content
CN103420833AActive Publication Date: 2013-12-04CHONGQING UNISPLENDOUR CHEM
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Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
CHONGQING UNISPLENDOUR CHEM
Publication Date
2013-12-04

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Abstract

The invention discloses a method for synthesizing p-toluenesulfonic acid-catalyzed dimethyl malonate. Chloroacetic acid is taken as a raw material, dimethyl malonate is generated through a neutralization reaction, a cyanation reaction, an acidification reaction, a hydrolysis reaction and an esterification reaction, the esterification reaction is performed under the catalytic effect of p-toluenesulfonic acid, a catalyst is recovered after the reactions, and the recovered catalyst can be recycled, so that the usage amount of the catalyst can be greatly reduced and sulfuric acid-containing wastewater cannot be produced by selecting p-toluenesulfonic acid instead of sulfuric acid in a traditional process as the catalyst in the esterification reaction; meanwhile, dichloroethane is added in the esterification reaction, has a good dissolving property for dimethyl malonate, is easily separated from dimethyl malonate through rectification and forms a ternary azeotropic system along with methanol and water, and the water generated in the reactions is continuously discharged from the system through azeotropy, so that the esterification reaction can be more thoroughly produced.
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Description

technical field

[0001] The invention relates to a method for preparing malonate, in particular to a method for synthesizing dimethyl malonate with chloroacetic acid and sodium cyanide as raw materials and catalyzed by p-toluenesulfonic acid. Background technique

[0002] Dimethyl malonate is an intermediate of medicines, pesticides and dyes. At present, there are many production methods at home and abroad. In China, cyanation esterification is mainly used, that is, chloroacetic acid, sodium cyanide and methanol are used as raw materials, and after neutralization , Cyanide, acidification and esterification processes to obtain dimethyl malonate.

[0003] Common synthetic methods:

[0004] 1. Direct esterification of cyanoacetic acid

[0005]

[0006] The shortcoming that this method exists is: the reaction process of synthesizing cyanoacetic acid produces a large amount of inorganic salt sodium chloride, and the mixture of cyanoacetic acid and salt carries out esterificat...

Claims

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