Green synthesis method of methyl-chloride

Abstract

The invention discloses a green synthesis method of methyl-chloride. The method comprises the following steps of S1, in a reaction system for preparing the methyl-chloride by taking the methyl sulfideand the chlorine as the raw materials, utilizing the characteristic that the disulfur dichloride can chlorinate the methyl sulfide, continuously reacting the disulfur dichloride generated during thereaction process with the methyl sulfide to convert into the methyl-chloride and the sulfur by controlling the introduction amount of the chlorine; and S2, after the reaction is completed, adding a catalyst A and a catalyst B into the reaction system, precipitating the sulfur in the system in the form of loose crystals, separating to obtain the sulfur and a methyl-chloride crude product, and carrying out rectification under vacuum to obtain the high-purity methyl-chloride. According to the method, not only the high-purity methyl-chloride can be prepared, the yield is increased, but also the crystalline sulfur with excellent properties can be obtained and can be reused, a large amount of salt-containing wastewater and the elastic sulfur waste residues are effectively avoided, the pollutioncaused by the waste gas is also avoided, the environmental protection is achieved, and the social benefits and the environmental benefits are remarkable.

Description

technical field [0001] The invention belongs to the technical field of preparation of pesticide intermediates, and in particular relates to a green synthesis method of methyl-chloride. Background technique [0002] O, O-dimethylphosphorothioate chloride (referred to as methyl chloride, the same below) is a special intermediate for the synthesis of phosphorothioate pesticides. Methyl-chloride can be used to prepare nearly twenty kinds of high-efficiency, medium-low toxicity organophosphorus pesticides, such as pirimiphos-methyl, chlorpyrifos-methyl, fenitrothion, tolclofos-methyl, etc. Among them, chlorpyrifos-methyl, chlorpyrifos, and pirimiphos-methyl are high-efficiency and low-toxic organophosphate varieties recommended by the Food and Agriculture Organization of the United Nations (FAO). In recent years, the demand for methyl-chloride in the pesticide market has shown an increasing trend year by year. [0003] At present, the mainstream methyl-chloride synthesis route ...

AI Technical Summary

Problems solved by technology

[0006] Though this method has solved the problem of disulfide dichloride, disulfide dichloride and sodium sulfide reaction process exotherm violently, and reaction system heats up faster; Because methyl-chloride stability is relatively poor, exceeds certain temperature easily Decomposes when heated, causing flushing or explosion risk

The by-product elastic sulfur has high viscosity, difficult to filter, strong odor and large quantity, so it can only be treated as waste residue

At the same time, after alkalization and hydrolysis, a large amount of sulfur- and phosphorus-containing foul-smelling wastewater is produced, and the environmental protection pressure of wastewater and waste residue treatment is huge.

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