Preparation method of carbosulfan

Abstract

The invention provides a preparation method of carbosulfan. The method comprises the following steps: (1) dissolving carbosulfan in an organic solvent, adding an acid-binding agent I triethylamine, performing stirring and mixing until uniformity, adding sulfur dichloride in a dropwise manner, and carrying out a thermal insulation reaction after the drop-by-drop addition is finished in order to prepare a sulfide solution; (2) adding di-n-butylamine, 4-dimethylaminopyridine and an acid-binding agent II triethylamine into the obtained sulfide solution, and, carrying out the thermal insulation reaction after the drop-by-drop addition is finished in order to obtain a carbosulfan reaction; and (3) washing the carbosulfan reaction solution until the reaction solution is neutral, separating out the obtained organic phase, and carrying out reduced pressure solvent removal to obtain the carbosulfan with the content of 96% or above, the yield of 98% or above and the harmful impurity carbofuran content of 0.1% or below. The method has the advantages of simplicity in operation, easily available raw materials and low cost, the prepared carbosulfan has the advantages of low content of main harmful impurities, high yield and high purity.

Description

technical field [0001] The invention belongs to the technical field of pesticide preparation, and in particular relates to a preparation method of carbosulfan. Background technique [0002] Carbofuran is a carbamate insecticide, a low-toxic carbofuran derivative developed by FMC Corporation of the United States. Due to the high toxicity of carbofuran, it is currently facing a ban, and the development of low-toxic derivatives of carbofuran has broad prospects. As a very important low-toxicity derivative of carbofuran, its toxicity is only ten times that of carbofuran. One-half (Zeng Xianze et al. "Chemical Synthesis of Carbosulfan", "Pesticides", Volume 34 No.6 (1995) P12 to 16). [0003] The preparation method of carbosulfan reported at home and abroad mainly contains following three kinds at present: [0004] (1) Di-n-butylamine is reacted with sulfur monochloride to prepare di-n-butylaminosulfur chloride, and then reacted with carbamoyl fluoride and furanol to prepare ca...

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Problems solved by technology

[0010] Both the first and second methods use sulfur monochloride as the starting raw material, with many reaction steps, long route, and cumbersome post-treatment, and both use the raw material sulfuryl chloride. The reaction must strictly control the moisture content, and the operation flexibility is small. A large amount of sulfur dioxide is produced, and the cost of tail gas treatment is high

In addition, US4329293 uses n-hexane as the reaction solvent, and n-hexane is extremely volatile, and there are safety risks. CN102786503A utilizes cosolvent N-methylpyrrolidone or dimethylamide to improve the solubility of carbofuran in the reaction solution, but the cosolvent The recovery loss rate is high, the wastewater treatment is difficult, and the production cost is high

[0011] In the third method, the yield reported by JP58026878 is 79.8%, and the product yield reported by US4413005 is 76.6%. The yields are both low and the preparation cost is high, and the obtained product carbosulfan contains unreacted raw materials Kebowei

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