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A kind of preparation method of ethyl 2,3-dicyanopropionate

A technology of ethyl dicyanopropionate and ethyl cyanoacetate, which is applied to the preparation of carboxylic acid nitrile, cyanide reaction preparation, chemical instruments and methods, etc., and can solve the problems of long reaction time, easy decomposition, and low synthesis efficiency , to achieve the effect of cost advantage, easy storage and simple operation

Active Publication Date: 2022-06-24
杭州臻峰科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In order to solve the problems existing in the background technology, the present invention proposes a kind of 2, the preparation method of ethyl dicyanopropionate, which solves the technical problems of low synthesis efficiency, difficult recovery of solvent, long reaction time and difficult storage of raw materials, Decomposable Defects

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Put 105 grams of liquid sodium cyanide aqueous solution with a mass fraction of 30% in a 500 ml reaction flask, heat the water bath to 90 ° C, use a vacuum water circulation pump to decompress and evaporate water until no obvious liquid flows out, cool down to 25-35 ° C and put in 400 g of sodium cyanide. Chloromethane was heated and separated into water until the water content of the solution was 1.0-3.0%. Cool down to 15°C and put in ethyl cyanoacetate: 70g paraformaldehyde 36g, dodecyltrimethylammonium bromide 1.3g, keep the internal temperature at 10-15°C, the reaction is over for 2-4 hours, prepare a 500ml reaction flask and add 240ml of 7.5% hydrochloric acid aqueous solution was cooled to 0-3°C, the above reaction solution was slowly poured into the prepared hydrochloric acid solution, stirred for 30 minutes, allowed to stand, layered, and the lower layer was the organic layer of methylene chloride. The organic layer of dichloromethane was washed twice with 100ml...

Embodiment 2

[0022] Put 105 grams of liquid sodium cyanide aqueous solution with a mass fraction of 30% in a 500 ml reaction flask, heat the water bath to 90 ° C, use a vacuum water circulation pump to decompress and evaporate water until no obvious liquid flows out, cool down to 25-35 ° C and put in 400 g of sodium cyanide. Chloromethane was heated and separated into water until the water content of the solution was 1.0-3.0%. Cool down to 15°C and put in ethyl cyanoacetate: 70g paraformaldehyde 36g, tetrabutylammonium bromide 1.4g, keep the internal temperature at 10-15°C and the reaction is over for 2-4 hours, prepare a 500ml reaction flask and add 7.5% 240 ml of aqueous hydrochloric acid solution was cooled to 0-3°C, the above reaction solution was slowly poured into the hydrochloric acid solution, stirred for 30 minutes, allowed to stand, and the layers were separated. The lower layer was the organic layer of dichloromethane. The organic layer of dichloromethane was washed with 100ml*2...

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Abstract

The invention discloses a preparation method of ethyl 2,3-dicyanopropionate. Put liquid sodium cyanide aqueous solution into the reaction tank, add dichloromethane to divide the water after concentration and dehydration; after passing the test, drop the temperature into ethyl cyanoacetate, paraformaldehyde and catalyst, keep the temperature until the end of the reaction, start to add hydrochloric acid for acidification, and let it stand for stratification An organic layer of dichloromethane was obtained; the organic layer was washed with water and the dichloromethane was removed to obtain a crude product, which was then rectified under reduced pressure to obtain a finished product. The present invention directly uses dichloromethane as a reaction solvent and adds a small amount of catalyst to shorten the reaction period, and the solvent is easy to recover. Compared with solid sodium cyanide, the used liquid sodium cyanide is cheaper to store and safer to use.

Description

technical field [0001] The invention discloses a preparation method of ethyl 2,3-dicyanopropionate, an intermediate of pesticides and insecticides, Fipronil. The process uses ethyl cyanoacetate as the main raw material, liquid sodium cyanide, paraformaldehyde, The catalyst is reacted in dichloromethane, acidified, washed with water, concentrated and synthesized by distillation. Background technique [0002] As the intermediate 2,3-dicyanopropionate of pesticides and insecticides, ethyl dicyanopropionate, DMSO is commonly used as the reaction solvent, solid sodium cyanide and paraformaldehyde are used as the reaction raw materials in the synthesis of patents in the past. Acidified with hydrochloric acid, extracted, washed with water, concentrated and synthesized by distillation. [0003] With the current national promotion of energy-saving, safe and environmentally friendly production, the pressure on factory environmental protection is increasing, the traditional DMSO synth...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C253/16C07C253/34C07C255/19C07C253/30C07C255/23
CPCC07C253/16C07C253/34C07C253/30C07C255/23C07C255/19
Inventor 张更真汪峰李昱达张国庆高彩霞张瑞玲
Owner 杭州臻峰科技有限公司