Continuous flow preparation method of diethyl methyl phosphite

Abstract

The invention discloses a continuous flow preparation method of diethyl methyl phosphite, which comprises the following steps: continuously adding ethanol and methyl phosphorus dichloride solution into a feed port of a continuous flow reactor, and continuously obtaining diethyl methyl phosphite at a discharge port of the continuous flow reactor. The method has the advantages of small liquid holdup, safe and efficient production process, solving of the problems of long reaction time and low efficiency in a kettle type reaction, high product yield and purity, and simple and efficient process operation.

Description

technical field [0001] The present invention relates to the preparation method of pesticide intermediate, more specifically relate to the continuous flow preparation method of diethyl methyl phosphite. Background technique [0002] Diethyl methyl phosphite is a key intermediate of the herbicide glufosinate-ammonium. [0003] Patents WO200905716, Tetrahedron (1982), 38, 2513, J.Am.Chem.Soc. (1958), 80, 1150, etc. disclose the preparation of methyl phosphorus dichloride and ethanol by esterification under the action of an acid-binding agent Diethyl methyl phosphite, the yield is about 90%. In this method, organic bases such as N,N-dimethylaniline or N,N-diethylaniline are used as acid-binding agents, which have the disadvantages of high price, cumbersome recovery process and low recovery rate. There are the problems of long time consumption, low efficiency and high safety risk in the dropping process. [0004] In the esterification reaction of methyl phosphorus dichloride a...

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Problems solved by technology

In this method, organic bases such as N,N-dimethylaniline or N,N-diethylaniline are used as acid-binding agents, which have the disadvantages of high price, cumbersome recovery process and low recovery rate. There are problems such as long time-consuming, low efficiency and high safety risks in the dropping process

[0004] In the esterification reaction of methyl phosphorus dichloride and ethanol, the patent CN107236002A uses sodium ethoxide as an acid-binding agent, which has an advantage over organic bases in terms of raw material cost, but there are still problems of long time consumption, low efficiency and large safety risks. question

Shi Hongxin and others disclosed the method of using ammonia as an acid-binding agent in "Jiangsu Chemical Industry". This method clearly stated that the pH of the reaction solution should be controlled at 7.0-8.5, and the ammonia flux and actual reaction speed should be strictly controlled during the operation. It is relatively difficult to achieve a balance between

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