GB572810A - Production of thioethers - Google Patents

Abstract

Thioethers containing more than four carbon atoms are prepared by reacting ethylene with hydrogen sulphide, methyl mercaptan or ethyl mercaptan, at a pressure of at least 500 atmospheres and a temperature of 120 DEG C. to 200 DEG C. The thioethers produced are of the formula R-S-R1, wherein R and R1 are alkyl radicals and at least one of them contains more than two carbon atoms. With ethylene and hydrogen sulphide the products are primarily products of the formula CH3CH2S(CH2-CH2)n-H where n is greater than unity and, in general, is from 2 to 6. In place of the above sulphhydryl compounds, compounds may be used which, under the reaction conditions, yield these compounds, e.g. water-soluble hydrosulphides of the alkali and alkaline earth metals. The reaction may be carried out in the presence or absence of solvents such as water and ethyl alcohol. Catalysts such as the sulphides of copper, zinc, lead, nickel and iron, and also molecular oxygen may be used. It is advantageous to employ a slightly acid medium such as water made acid with a non-oxidizing acid. The thioethers are useful in the rubber, cosmetic and pharmaceutical industries; as solvents; and as intermediates in the production of sulphoxides, sulphones and sulphonium compounds which are useful as plasticizers, surface-active agents and textile assistants. In examples: (1) ethylene and hydrogen sulphide are heated in a closed vessel containing water acidified with hydrochloric acid to a pH of 2.3, under a pressure of 850-940 atmospheres and at 198-201 DEG C. for 10 hrs. The reaction product is separated from the aqueous layer, dried and fractionally distilled, yielding diethyl sulphide, an intermediate thioether, butyl ethyl sulphide and a higher boiling thioether; (2) similar to (1), the pressure being 700-900 atmospheres and temperature 163-189 DEG C. The fractions boiling higher than diethyl sulphide, from a number of such runs after fractionation yield diethyl sulphide, butyl ethyl sulphide (identified by oxidation with hydrogen peroxide forming the corresponding sulphone), and ethane dithiol diethyl ether (identified similarly).