GB632306A - Improvements in or relating to heterocyclic sulphur compounds and process of preparing same - Google Patents

Abstract

Heterocyclic compounds containing a thiophene nucleus are produced by passing hydrogen sulphide or volatile thermally-labile sulphide, and an organic compound containing an aliphatic chain of at least 3 carbon atoms in vapour phase at a temperature of at least 700 DEG F. into contact with a surface-active, preferably a dehydrogenation catalyst. Suitable organic compounds include saturated acyclic hydrocarbons or mixtures containing them, aryl-substituted aliphatic compounds, halogenated aliphatic compounds, and saturated or unsaturated aliphatic alcohols. The sulphides include those of the non-metals and metalloids. aliphatic mercaptans and sulphides, for example ammonium sulphide, hydrosulphide and polysulphide, ethyl and tertiary butyl mercaptan and sulphide. Catalysts include metal and metalloid oxides and sulphides, especially those of Groups 5 to 8, for example chromia-alumina and molybdenum sulphide-alumina. The mol ratio of sulphide to organic compound charged is at least 0.1, and space velocity of said compound at least 0.3 liquid vols./vol./hr. Preferred conditions for reacting butane with hydrogen sulphide are about 1100 DEG F., mol. ratio 1, and space velocity 1.5. Fixed bed or fluidized catalyst may be used. The thiophene compounds may be recovered by passing the products into a cooled oil from which the thiophenes can be distilled, or by first washing the products with hot caustic soda and then condensing. Examples describe the production of thiophene from n-butane or a mixture of n- and iso-butane and hydrogen sulphide, using chromia-alumina or molybdena-alumina. Specifications 305,603, [Class 2 (iii)], 454,668 and 603,103 are referred to.