Novel process and synthesis device for preparing glyphosate by hydrolyzing by-product acid instead of hydrochloric acid

Abstract

The invention discloses a novel process and a synthesis device for preparing glyphosate by hydrolyzing by-product acid instead of hydrochloric acid. The novel process comprises the steps of (1) preparing a synthetic liquid L1 by taking glycine, dimethyl phosphite and paraformaldehyde as raw materials, methanol as a solvent and triethylamine as a catalyst; (2) adding post-treatment hydrochloric acid into the synthetic liquid L1 for hydrolysis and desolvation, and adding alkali to adjust the pH after hydrolysis and desolvation; and (3) adding deionized water, cooling, stirring and crystallizingto obtain a crystallization solution L2, washing and drying to obtain a glyphosate finished product. According to the invention, improvement is carried out on the basis of glyphosate production by a glycine alkyl ester method, a by-product hydrochloric acid for preparing phosphorus trichloride is adopted to replace hydrochloric acid to hydrolyze a synthetic liquid after post-treatment, and meanwhile, each key process index parameter is optimized, so that the utilization rate of the by-product acid in a chemical industrial park is increased, and the yield and the purity of the glyphosate raw powder are greatly improved. Meanwhile, because a large amount of water carried by the introduction of hydrochloric acid is avoided, the recovery energy consumption of by-products such as methanol and the like and the discharge amount of wastewater are also reduced.

Description

technical field [0001] The invention relates to the technical field of glyphosate pesticide production, in particular to a new process and synthesis device for preparing glyphosate by hydrolysis of by-product acid instead of hydrochloric acid. Background technique [0002] Glyphosate, the English common name glyphosate, alias N-(phosphonic acid methyl) glycine, also known as zhencaoning, Benda, etc., is an agricultural chemical, which is a low-toxic systemic conduction type broad-spectrum weed control agent. It is mainly used in commercial crop gardens such as orchards, and has a significant effect on the control of perennial malignant weeds. At present, there are two mainstream production routes at home and abroad. One is to use iminodiacetic acid (IDA) as raw material. The process is simple, the process conditions are relatively mild, and the product yield is high. There are few restrictions in domestic application. At present, large foreign companies mostly use this proc...

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Problems solved by technology

[0003] However, the traditional hydrolysis process is complicated, and the reaction between by-products or between by-products and raw materials seriously restricts the further optimization of glyphosate synthesis process.

Moreover, hydrochloric acid mainly comes from the recovery and reuse of dimethyl phosphite by-product hydrogen chloride, which needs to be condensed, washed with water and alkaline, and the refining process is complicated

Chinese patent application number 201910453082.8 discloses a method and device for applying dimethyl phosphite hydrogen chloride tail gas to the synthesis of glyphosate, and proposes to directly use hydrogen chloride instead of hydrochloric acid for hydrolysis to reduce waste water discharge. However, the utilization rate of hydrogen chloride It is only 20%. In addition, hydrogen chloride is not easy to measure as a gas, and it is difficult to transport it to the reaction system, and it consumes a lot of energy.

Therefore, how to effectively avoid the hydrolysis of other by-products containing methoxy groups in the esterification stage through temperature control in the desolventization stage, and precisely improve the directional production of glyphosate is a major problem in the glyphosate industry; Formaldehyde and dimethyl phosphite are usually added in excess, which makes the intermediate reaction more complicated; it is generally believed that side reactions are positively correlated with temperature, but many other processes reported ignore this, such as the feeding temperature of dimethyl phosphite , if it is too high, it will lead to the formation of intermediates such as dimethyl hydroxymethyl phosphate, which will seriously affect the yield, which is also the deficiency of previous studies

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