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Method for producing methyl mercaptan from dialkyl sulfides and dialkyl polysulfides

A technology of dialkyl sulfide and polysulfide, which can be used in the preparation of mercaptans, organic chemistry, etc., and can solve problems such as toxicity

Inactive Publication Date: 2010-02-10
EVONIK DEGUSSA GMBH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The disadvantage of this method is that toxic carbon disulfide is used in the process, which must be separated again from the reaction product in an expensive manner

Method used

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  • Method for producing methyl mercaptan from dialkyl sulfides and dialkyl polysulfides
  • Method for producing methyl mercaptan from dialkyl sulfides and dialkyl polysulfides
  • Method for producing methyl mercaptan from dialkyl sulfides and dialkyl polysulfides

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Embodiment 1

[0034] Example 1 shows by way of example the synthesis of the catalyst, while Example 2 describes the catalytic cleavage of dimethyl sulfide to methyl mercaptan.

[0035] Example 1: M 2 O-Al 2 o 3 Preparation of (M=Li, Na, K, Rb, Cs)

[0036] 49.66g of LiNO 3 Dissolve in 30ml of distilled water. The solution was heated to about 60°C so that the salt could be completely dissolved. 50 g of gamma-alumina was added to the solution with stirring. The solution was then stirred for about 60 minutes. The catalyst is stirred at a temperature of at least 60°C, optionally under reduced pressure, until all the liquid is absorbed into the support. The catalyst was dried overnight in air at about 120°C and then calcined at 500°C for 3 hours in a stream of air.

Embodiment 2

[0038] DMS cracking was studied at a temperature range of 100-500°C and a pressure of 1.5-25 bar. The ratio of hydrogen sulfide to dimethyl sulfide (DMS) in the reaction gas is in the range of 1:1-25:1.

[0039] The fresh catalyst was first sulfided in the reactor at 350° C. for 2.5 hours in a stream of hydrogen sulfide before starting the reaction. figure 2 shows that for Rb 2 O-Al 2 o 3 (spheralite), with classical "top feeding" (fixed bed reactor with one catalyst zone) and in "two-zone operation" (i.e., similar to that with H 2 S stage reactor with intermediate feed, H 2 S streams are fed upstream of the two catalyst zones) Comparison of the cracking conversion of dimethyl sulfide to methyl mercaptan as a function of temperature for the two cases. In both cases, the total H 2 The ratio of S to DMS was 14:1. The space velocity and gas loading are the same in both cases. figure 2 Illustrated, in the apparatus of the present invention, by the catalysts modified with...

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Abstract

The invention relates to a method for the continuous production of methyl mercaptan by reacting an educt mixture containing dialkyl sulfides and dialkyl polysulfides, with hydrogen sulfide in order to form methyl mercaptan.

Description

technical field [0001] The invention relates to a process for the preparation of alkylmercaptans by reacting a reaction mixture comprising dialkylsulfides and / or dialkylpolysulfides and optionally dialkylethers with hydrogen sulfide over a heterogeneous catalyst. Background technique [0002] Methyl mercaptan is an important industrial intermediate for the synthesis of methionine and the preparation of dimethyl sulfoxide and dimethyl sulfone. Methyl mercaptan is mainly produced by the reaction of methanol and hydrogen sulfide in the presence of a catalyst consisting of an alumina support and a transition metal oxide and a basic cocatalyst. [0003] In the reaction of methanol and hydrogen sulphide, an economically feasible excess of hydrogen sulphide is employed at the usual reaction temperatures, thereby resulting in a reaction equilibrium in which dimethyl sulphide and methyl mercaptan are always formed. In addition to the formation of thioethers, the reaction was found t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C319/06C07C319/08C07C321/04
CPCC07C319/08C07C319/06C07C321/04
Inventor J-O·巴尔特H·雷德林绍弗尔C·韦克贝克K·胡特马赫尔
Owner EVONIK DEGUSSA GMBH
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