Synthesis process of glyphosate intermediate dimethyl phosphite

Abstract

The present invention relates to a synthesis process of glyphosate intermediate dimethyl phosphite, the steps are as follows: methanol is metered through a methanol metering tank and enters an esterification reactor, phosphorus dichloride is metered through a metering tank and enters the esterification reactor, materials enter the esterification reactor simultaneously in ratio, after esterification reaction, a material liquid flows into a deacidification kettle via an inner liquid seal tube, a gas generated by the esterification reaction returns back to the esterification reactor via a first condenser and a secondary condenser, hydrogen chloride is removed form the material liquid in the deacidification kettle under high vacuum and steam heating conditions, and after deacidification by the deacidification kettle, the material liquid enters a rectifying kettle for rectifying. Continuous production of the dimethyl phosphite can be achieved, a great development space is provided for production capacity improvement and further significant reduction of operating cost, and purity is increased to 99.0% or more.

Description

technical field [0001] The invention relates to the field of pesticide processing, in particular to a synthesis process of a glyphosate intermediate dimethyl phosphite. Background technique [0002] Dimethyl phosphite is an important product in fine chemical industry. It is not only an intermediate for the production of glyphosate, trichlorfon, rice blast, omethoate and other pesticides, but also a raw material for organophosphorus corrosion inhibitors, dye additives, plastic additives and flame retardants, and can be used for synthetic water treatment It can also be used as a methylating agent to synthesize quaternary ammonium salt fungicides, antistatic agents, softeners and other products. [0003] Dimethyl phosphite is generally prepared industrially from the reaction of phosphorus trichloride and methanol: PCl 3 +3CH 3 OH→(CH 3 O) 2 POH+2HCl↑+CH 3 The Cl↑ reaction process and mechanism are: [0004] PCl 3 +CH 3 OH→CH 3 OPCl 2 +HCl↑(1) [0005] CH 3 OPCl 2 ...

AI Technical Summary

Problems solved by technology

[0011] At present, the industrial production of dimethyl phosphite has been using the batch method of single-pot reaction and single-pot rectification. The reaction materials are fed through the high-level tank, and the measurement control is difficult, and the reaction needs to be controlled below 55°C. , frequent operations, high labor intensity, long production cycle and low equipment capacity

At the same time, the heat of reaction needs to be removed by freezing during the reaction process, and the material needs to be heated during deacidification, so the energy utilization rate in the production process is low