GB603700A - Improvements in or relating to the production of vinyl cyanide - Google Patents

Abstract

Oxides of zinc, cadmium and magnesium which may also be associated with oxides of manganese, tin and thorium, alkali metal cyanides or the metal chromites described in Specification 603,699 may be used in the preparation of vinyl cyanide by the vapour phase reaction of acetylene and hydrogen cyanide (see Group IV (b)). The oxides may be prepared by direct oxidation of the metals or by thermal decomposition or oxidation of inorganic or organic compounds of the metal, for example the metal salts of organic acids; the oxides may be associated with supports and may be pelleted. Examples describe catalysts comprising a zinc-manganese oxide, a zinc-cadmium oxide and magnesium oxide, prepared by ignition of the metal oxalates (mixed in the case of the double oxides) followed by pelleting.ALSO:Vinyl cyanide is prepared by reacting acetylene and hydrogen cyanide in the vapour phase in the presence of an oxide of zinc, cadmium or magnesium. The preferred catalyst is a mixture of zinc and magnesium oxides. The catalyst mass may also include oxides of manganese, tin and thorium, alkali metal cyanides and the chromites described in Specification 603,699. The preparation of the oxide catalysts is given (see Group III). In examples, mixtures of acetylene, hydrogen cyanide and hydrogen are reacted over (1) a zinc-cadmium oxide at 475 DEG C., (2) a zinc-manganese oxide at 500 DEG C. and (3) magnesium oxide at 500 DEG C.