Synthesizing process of 2,3-dicyanoethylpropionate

Abstract

The invention relates to a synthesizing process of 2,3-dicyanoethylpropionate. The process comprises the steps that: electric stirring is started; dimethyl sulfoxide is sucked by using vacuum, and a cooling valve is opened for cooling; ethyl cyanoacetate is sucked; when the temperature is reduced to 4-6 DEG C, paraformaldehyde is added, and sodium cyanide is added; when dosing is finished; heating is carried out for azeotropy; sodium thiosulfate is added, and hydrochloric acid is dropped in, such that a pH value reaches 3-4; a dichloroethane extractant is rapidly added, and the mixture is settled and stratified; an upper-layer material and dichloroethane are delivered to a secondary reaction kettle, and lower-layer water and dimethyl sulfoxide are recovered; the stratified material is pumped into a desolventizing kettle, and dichloroethane is recovered, such that a 2,3-dicyanoethylpropionate crude product is obtained; and rectification is carried out, such that a 2,3-dicyanoethylpropionate finished product is obtained. The process provided by the invention has the advantages that: the synthesizing temperature is controlled at 5+/-1DEG C; reaction is smooth; side reaction is prevented; and yield is high. The extraction effect of dichloroethane upon the 2,3-dicyanoethylpropionate crude product is better, wherein an extraction rate reaches 97%, such that product yield is greatly improved.

Description

technical field [0001] The invention relates to a synthesis process of ethyl 2,3 dicyanopropionate, which belongs to the field of chemical industry. Background technique [0002] At present, the output of chemical products such as medicines and pesticides in my country has continued to grow steadily, which in turn drives the continuous and steady growth of its synthetic intermediates, and the market demand for intermediates has further expanded. The synthesis of the original ethyl 2,3 dicyanopropionate In the process, the temperature of the reaction system is controlled too high, reaching 20-30°C. During the reaction process, there are many side reactions, the materials are easy to polymerize, and a lot of hazardous waste is produced. The yield is low; the choice of extraction agent directly affects the yield of the crude product. Moreover, due to the difference in the extractant, the extraction effect is not high, which directly leads to an increase in the amount of crude pro...

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Problems solved by technology

[0002] At present, the output of chemical products such as medicines and pesticides in my country has continued to grow steadily, which in turn drives the continuous and steady growth of its synthetic intermediates, and the market demand for intermediates has further expanded. The synthesis of the original ethyl 2,3 dicyanopropionate In the process, the temperature of the reaction system is controlled too high, reaching 20-30°C. During the reaction process, there are many side reactions, the materials are easy to polymerize, and a lot of hazardous waste is produced. The yield is low; the choice of extraction agent directly affects the yield of the crude product. Moreover, due to the different extraction agents, the extraction effect is not high, which directly leads to an increase in the amount of crude products contained in the process wastewater, and the COD of the wastewater is obviously high, which brings difficulties to wastewater treatment.

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