Catalyst for synthesizing isopropyl mercaptan from propylene and hydrogen sulfide

Abstract

The invention discloses a catalyst used in synthesizing isopropanethiol from propylene and hydrogen sulfide and a preparation method of the catalyst. A carrier is aluminum oxide, metal components are Group VIB metals and Group VIII metals and the additive is a ZSM-5 molecular sieve. The catalyst is suitable for the reaction for synthesizing isopropanethiol from propylene and hydrogen sulfide, under the condition of more moderate operation, the conversion rate per pass of propylene can reach 85%, the selectivity of isopropanethiol is greater than 95% and the service life of the catalyst is 2 years.

Description

technical field [0001] The invention belongs to the field of chemical industry, and in particular relates to a catalyst for catalytically synthesizing isopropyl mercaptan from propylene and hydrogen sulfide. 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) is reacted 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 hy...

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Problems solved by technology

[0004] 1) The alcohol solution of sodium hydrosulfide (potassium) is reacted with 2-bromopropane, which is easy to generate by-product isopropyl sulfide

[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 complex

[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

The catalyzer that this method uses is the alumina catalyst of modification, and isopropyl mercaptan yield is lower

[0008] 4) Propylene and hydrogen sulfide are used to prepare isopropyl mercaptan by plasma method. It is pointed out that isopropyl mercaptan can be prepared by using propylene and hydrogen sulfide 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

[0016] Studies have shown that the catalyst with adsorption and dissociation effects on hydrogen sulfide is a catalyst with an acidic center, and the dissociation of hydrogen sulfide and the formation of carbonium ions need to reach their activation energy, and the addition of the catalyst also reduces the above two activation energy of the step

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