Method for preparing isopropyl mercaptan

Abstract

The invention discloses a method for synthesizing isopropyl mercaptan from propylene and hydrogen sulfide. According to the method, a heat insulation type fixed bed reactor is used and isopropyl mercaptan is synthesized of hydrogen sulfide and propylene in the presence of a solid acid catalyst according to a continuous production process. The method disclosed by the invention has the advantages that the reaction conditions are easy to control, the yield is high, the process is simple, and the environmental pollution is reduced.

Description

technical field [0001] The invention belongs to the field of chemical industry, in particular to a preparation method of isopropyl mercaptan. Background technique [0002] Isopropyl mercaptan is one of the important varieties of low-carbon mercaptan series. It is an important chemical raw material and intermediate. It occupies an important position in the field of synthetic pesticides. The market demand is increasing year by year. At present, my country's isopropyl mercaptan mainly relies on imports. [0003] The synthesis of isopropyl mercaptan can take the following methods: [0004] 1) The alcoholic solution of sodium hydrosulfide (potassium) reacts with 2-bromopropane, and this method easily has by-product isopropyl sulfide to generate; [0005] 2) 2-bromopropane reacted with thiourea in ethanol solution for 4 hours, and distilled off the ethanol to obtain S-isopropyl isothiourea salt. The salt was hydrolyzed in alkali solution, and then acidified to obtain isopropyl me...

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Problems solved by technology

[0004] 1) The alcoholic solution of sodium hydrosulfide (potassium) reacts with 2-bromopropane, and this method easily has by-product isopropyl sulfide to generate;

[0005] 2) 2-bromopropane reacted with thiourea in ethanol solution for 4 hours, and distilled off the ethanol to obtain S-isopropyl isothiourea salt. The salt was hydrolyzed in alkali solution, and then acidified to obtain isopropyl mercaptan , the method is complicated to operate;

[0006] Above two kinds of methods all adopt intermittent operation, and mercaptan volatilizes in the air during operation, and smell is unpleasant, pollutes environment, is the method for laboratory preparation a small amount of isopropyl mercaptans, is difficult to realize suitability for industrialization, simultaneously the isopropyl mercaptan of these two kinds of methods The yield of propanethiol is not high (about 81%)

[0007] 3) Isopropyl alcohol and hydrogen sulfide are catalyzed to synthesize isopropyl mercaptan with modified alumina as a catalyst. During the reaction process, water is generated, and the generated water and unreacted hydrogen sulfide form a strong corrosive fluid, which has extremely high requirements for equipment anti-corrosion. High, at the same time generate wastewater containing mercaptans and sulfides, which is difficult to treat

[0008] 4) Propylene and hydrogen sulfide use plasma method to prepare isopropyl mercaptan. Relevant patents point out that propylene and hydrogen sulfide can be used to prepare isopropyl mercaptan in a plasma reaction chamber. This reaction process requires the use of special equipment such as a plasma reaction chamber , while using the plasma electric field to generate high-energy state electrons, which is difficult to industrialize

"Synthesis of isopropyl mercaptan by sodium hydrosulfide method and basic theoretical research" mentioned that "at present, the industrial methods for synthesizing isopropyl mercaptan in foreign countries mainly include the substitution reaction of isopropanol with hydrogen sulfide under the action of a solid catalyst; the reaction of propylene under the action of a catalyst Addition reaction with hydrogen sulfide, but the water and hydrogen sulfide generated by this method form a strong corrosive fluid, which requires high equipment, difficult process and high cost

In addition, the related patents also mentioned the report on the synthesis of isopropyl mercaptan from propylene and hydrogen sulfide. The method used in this technology is the plasma method, which requires the use of special equipment such as a plasma reaction chamber, and at the same time uses the plasma electric field Generate high-energy state electrons, which are difficult to industrialize

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