Method of controlling harmful impurities during pirimiphos-methyl synthesis

Abstract

The invention discloses a method of controlling harmful impurities during pirimiphos-methyl synthesis. The method includes following steps: adding 2-N, N-diethylamino-6-methyl-4-hydroxy pyrimidine metal salt and a catalyst into an organic solvent; dropwise adding O, O-dimethyl thiophosphoryl chloride for condensation reaction; after-treating obtained reaction liquid to obtain pirimiphos-methyl to complete control on harmful impurities. By the method, content of the harmful impurities can be controlled effectively, and amounts of the harmful impurities like methyl sulfotepp (<0.06%) and iso-pirimiphos-methyl (<0.2%) are far lower than FAO limited concentration standards.

Description

technical field [0001] The invention belongs to the technical field of sanitary medicine preparation, and in particular relates to a method for controlling harmful impurities in the synthesis of pirimiphos-methyl. Background technique [0002] Pirimiphos-methyl is a low-toxicity (LD50 is 2050mg / kg), high-efficiency (the dosage for grain storage is 8ppm), and low-residue pesticide. In developed countries, it is used as a household hygiene drug. [0003] Although pirimiphos-methyl is a low-toxicity insecticide and can be widely used, in 2007, the FAO reported on carcinogenic and teratogenic harmful impurities O, O-dimethylphosphoryl thiochloride (methyl chloride) in the original drug of pirimiphos-methyl , O, O, S-trimethylphosphorodithioate, O, O, S-trimethylphosphorothioate, O, O, O-trimethylphosphorothioate and isomethyl pyrimiphos The content has strict requirements (be controlled below 0.5%), and other impurities that are highly toxic to humans and animals must be less ...

AI Technical Summary

Problems solved by technology

Although this patent can greatly reduce the generation of harmful impurities by adding hydrolysis inhibitors and catalysts, due to the use of water and sodium hydroxide, it is impossible to avoid the highly toxic and teratogenic methylthiotope (O, O, O , O-tetramethyl dithiopyrophosphate) etc., the content of methyl thiotop in the product is 0.11% to 0.37%, and O, O, O-trimethyl phosphorothioate are all greater than 1%, which is Two impurity indicators can not meet the FAO standard

[0006] Nie Ping et al. (Fine Chemical Intermediates, 2010, No. 1) used methyl chloride and 2-N, N-diethylamino-6-methyl-4-hydroxypyrimidine as raw materials, and sodium hydroxide as acid-binding agent, toluene is the solvent, sodium sulfate is added as the hydrolysis inhibitor, and the reaction temperature is 25-35° C. to obtain pirimiphos-methyl with a content of 99%, and the yield is 94%. The related harmful impurities are not controlled

Images