Method for synthesizing glufosinate ammonium salt

Abstract

The invention discloses a method for synthesizing a glufosinate ammonium salt. The method comprises the following steps that (1) methyldiethoxyphosphine and n-butanol are used as raw materials to produce an intermediate I by hydrolysis and transesterification; (2) the intermediate I is subjected to a free radical addition reaction with acrolein cyanohydrin acetate to form an intermediate II; (3) the intermediate II is subjected to an aminolysis reaction with ammonia gas to form a mixture of an intermediate III and an intermediate IV; (4) the intermediate III and the intermediate IV are subjected to acid hydrolysis with hydrochloric acid to form an intermediate V; and (5) the intermediate V is neutralized, purified and crystallized to obtain the glufosinate ammonium salt. The method does not need to use toxic raw materials, avoids the large-scale use of ammonia water and ammonium chloride, not only greatly reduces the safety hazard, but also reduces the quantity of by-products and the amount of waste water generated, and the environmental protection risk is greatly reduced; and the purification process is simple, the product content and the yield coefficient are obviously increased,and the method is suitable for industrial scale production.

Description

technical field [0001] The invention relates to a synthesis method of glufosinate-ammonium ammonium salt, belonging to the technical field of pesticide synthesis. Background technique [0002] Glufosinate-ammonium is a highly efficient, low-toxic, non-selective (killing) contact organic phosphine herbicide with partial systemic action, used for the control of annual and perennial herbicides in orchards, vineyards, potato fields, non-cultivated land, etc. Dicotyledonous and gramineous weeds are already the second most herbicide species in the world. It was first developed by the German company Hoechst, and its synthesis methods include fermentation and chemical synthesis. The fermentation method is mainly produced by microbial fermentation with bialaphos, which has been gradually replaced by chemical synthesis because it is not suitable for large-scale mass production. Most chemical synthesis methods use diethyl methyl phosphite or methyl phosphorus dichloride as intermedia...

AI Technical Summary

Problems solved by technology

Although the synthesis method is milder, it still has obvious deficiencies. For example, ① about the intermediate diethyl methylphosphonite, it is mostly starting with phosphine trichloride, triethyl phosphite, and Grignard methylmagnesium chloride. Raw material preparation, the raw material is highly toxic and active, and it is very easy to react with water in the air to cause accidents; ② Regarding the synthesis of the intermediate methyl phosphine dichloride, whether it is synthesized by using aluminum powder and methyl chloride phosphorus trichloride as raw materials Methane and phosphorus trichloride are still used as raw materials for synthesis, and the risk of production is very high; the reaction temperature is as high as 500 ° C ~ 600 ° C, the corrosion of equipment is very serious, and there are disadvantages such as unstable control of the intermediate process

Methyl phosphorus dichloride is very easy to spontaneously ignite with air, which is a great test for the safety of its storage process; ③strecker reaction requires a large amount of ammonia, ammonium chloride and highly toxic sodium cyanide, which has a great impact on the environment and this reaction can produce a large amount of ammonium chloride, is difficult to separate with glufosinate-ammonium, and the technology of separation and purification is loaded down with trivial details, and product yield is seriously affected, and yield can only reach about 30% (with diethyl methylphosphonite calculation), and requires a large investment in by-product purification and wastewater treatment equipment, and the production cost remains high

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