GB773697A - Method for producing dimethyl sulphide - Google Patents

Abstract

Dimethyl sulphide is produced by passing a mixture of methanol with hydrogen sulphide or methyl mercaptan, at a temperature within the range 280 DEG to 475 DEG C., over a catalyst consisting substantially entirely of aluminium oxide. The catalyst may consist of pure, commercial or naturally occurring aluminium oxides or bauxite. The catalyst may be precipitated on a carrier such as fuller's earth, kieselguhr, pumice, active carbon and bleaching earth. The reaction may be effected at atmosphoric, increased or reduced pressure and an inert gas, e.g. nitrogen, may be used as a diluting agent. The molar ratio of methanol to hydrogen sulphide may vary from 0.65 to 3.0 but is preferably between 1.0 and 1.6. A suitable apparatus is described comprising an electrically heated furnace containing catalyst and surrounded by asbestos. The products leaving the furnace are cooled and collected in an ice-cooled receiver which is followed by wash-bottles containing lye to take up excess hydrogen sulphide and mercaptan formed. The methyl mercaptan may be isolated and re-used in the process. Detailed examples are furnished in which the catalyst is pure or commercial aluminium oxide and comparative examples illustrate the use of mixtures of aluminium oxide with ferric oxide and thorium oxide.