A method for co-producing sodium methyl mercaptide, dimethyl sulfide and dimethyl disulfide

Abstract

The invention relates to a method for co-producing sodium methyl mercaptide, dimethyl sulfide and dimethyl disulfide. The method comprises: mixing aqueous solution of sodium hydrosulfide and an organic solvent, adding acid to regulate pH to 9 to 10, and then slowly filling chloromethane gas into the mixture to perform a reaction; after reaction, layering materials obtained in the reaction so as to obtain a first oil phase and a first water phase, and carrying out mixing and extraction on the first oil phase and sodium hydroxide solution to obtain a second water phase and a second oil phase; filtering the second water phase to remove impurities so as to obtain sodium methyl mercaptide solution; recycling the second oil phase used as the organic solvent, and when content of dimethyl sulfide is high, respectively recovering dimethyl sulfide and dimethyl disulfide in the second oil phase by rectification. According to the invention, used raw materials are low in toxicity; reaction time is short; reaction conditions are mild; the method is simple to operate; product yield is high; the method is simple in post-processing, can be widely used for industrial production and has higher economic value.

Description

technical field [0001] The invention relates to a safe and environment-friendly method for simultaneous co-production of sodium methyl mercaptide, dimethyl sulfide and dimethyl disulfide, which belongs to the technical field of chemical industry. Background technique [0002] The appearance of sodium methyl mercaptide is a colorless transparent liquid with an odor. It is a strong alkaline liquid and can be used as a raw material for pesticides, medicines, and dye intermediates. At present, the production process of sodium methyl mercaptide mostly adopts the reaction of sodium hydrosulfide and dimethyl sulfate (or methyl chloride) to generate methyl mercaptan gas, which is then absorbed into a 20% sodium methyl mercaptide solution with liquid caustic soda. The production process of sodium hydrosulfide requires a large amount of processes, and will produce stench, toxic pollutants, waste water containing sodium hydrosulfide and a small amount of volatile methyl sulfide, which ...

AI Technical Summary

Problems solved by technology

The production process of sodium hydrosulfide requires a large amount of processes, and will produce stench, toxic pollutants, waste water containing sodium hydrosulfide and a small amount of volatile methyl sulfide, which will cause great pollution to the environment and affect the product to a certain extent. market supply

[0003] Chinese patent CN 102976987 A discloses a method for the co-production of sodium methyl mercaptide and dimethyl sulfide, which has the following disadvantages: (1) A four-stage series reaction is adopted. On the one hand, it is necessary to continuously absorb methyl mercaptan. In the process, the risk of methyl mercaptan gas overflow is increased, which further affects the environment. On the other hand, the residence time of methyl chloride gas is short, and the single reaction efficiency of methyl chloride is low, so the reaction between methyl chloride and sodium hydrosulfide is not fast, and affects The concentration of sodium methyl mercaptide solution will affect the later products; (2) The continuous introduction of methyl chloride gas will be connected to the absorption device behind, and the methyl chloride will react with liquid caustic soda to form methanol, which will affect the synthesis of later products; (3) ) process production is carried out under negative pressure, which requires high equipment, which increases investment and operating costs, and increases energy consumption; Increased investment and operating energy consumption