Production process of O, O-dialkyl thiophosphoryl chloride

Abstract

The invention relates to a production process of O, O-dialkyl thiophosphoryl chloride, which improves the production process of the O, O-dialkyl thiophosphoryl chloride produced by a phosphorus pentasulfide method. An O, O-dialkyl thiophosphoryl chloride product is synthesized by adding a by-product obtained by reacting phosphorus pentasulfide with alkanol and introducing chlorine to O, O-dialkyl phosphorus chloride obtained by reacting trialkyl phosphite with phosphorus trichloride. The invention can achieve the total yield of the trialkyl phosphite by 94 percent and the total yield of the phosphorus pentasulfide more than 95 percent and has safe production, little energy consumption and pollution without generating sulphur residues.

Description

technical field [0001] The present invention relates to the chemical production of O,O-dialkylphosphorylthiochlorides, such as O,O-dimethylphosphorylchloride and O,O-diethylphosphorylchloride. technical background [0002] (1) At present, the production of O, O-dimethylphosphoryl thiochloride in China adopts the reaction of phosphorus trichloride and sulfur to generate phosphorus trichloride, and the reaction of phosphorus trichloride and excess methanol generates O-methylphosphorothioate Acyl dichloride (referred to as dichloride), dichloride reacts with excess methanol in the presence of a base to generate O, O-dimethylphosphoryl thiochloride (abbreviated as monochloride). [0003] During production, sulfur reacts with phosphorus trichloride to generate phosphorus trichloride, and its yield and content can reach 97%. When phosphorus trichloride reacts with methanol to generate dichloride, methanol must be in large excess, and its molar ratio is three Chlorathion:methanol=...

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Problems solved by technology

[0014] In addition, methanol is excessive in the production of dichloride and monochloride. If methanol is not recovered, it will cause great pollution to the environment, and cause great economic losses. Therefore, the process must have a strong The methanol recovery system consumes a large amount of steam per ton of chloride

[0015] (2) The production of O, O-diethylphosphoryl thiochloride can also be obtained by the reaction of phosphorus trichloride and absolute ethanol in the presence of alkali, but at present there is no domestic enterprise using this method to produce

[0023] The purity of the product produced by this process can reach more than 99%, but as can be seen from the above reaction formula, a large amount of HCl, H 2 S, S and NaCl, these by-products cause great difficulties to recovery and post-processing, the by-products in the process of treatment cause great pollution to the environment, and are not easy to recycle and treat, while the waste gas, waste water, and waste residue generated during production It also makes the on-site operators and surrounding personnel unbearable

[0024] Due to many by-products, the yield of the product to phosphorus pentasulfide is only 75-85%.

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