The invention provides a synthesizing method of
chlorpyrifos primary drugs. The method comprises the following steps of: dosing 2,3,5,6-tetrachloropyridine and NaOH with the
volume concentration of 30% into a high-pressure
autoclave in one time, insulating the reacting materials at a temperature of between 145 and 155 DEG C for 5 hours, and cooling and crystallizing to obtain a 3,5,6-trichloropyridin-2-ol
sodium; injecting water into another reaction kettle, and dosing an emulsifier which accounts for 0.1 to 0.15 percent of the
mass of the water, and catalyst 4-dimethylaminopyridine which accounts for 0.1 percent of the
mass of the water into the water, stirring for 15 minutes, dosing the 3,5,6-trichloropyridin-2-ol
sodium which is in a ratio of 1:(2.8-3.0) with the
water mass into the reaction kettle, and dripping O,O-diethyl
thiophosphoryl chloride until the reaction is completed. The synthesizing method has the advantages of simple process, small hurt to human, small environment
pollution, high yield and purity, and the like, the technical problems of low content and low yield of a traditional aqueous phase process for synthesizing
chlorpyrifos crude oil can be solved, and the environment can be effectively protected.