Production of silicon chlorides

摘要

Disilicon hexachloride and its higher homologues are prepared by reacting at least one of the group consisting of silicon and ferrosilicon with chlorine in the presence of a chloride of at least one of the group consisting of ammonia and the metals of Groups I and II. Column A of the Periodic Table whilst maintaining the reaction temperature below 250 DEG C. and not less than 140 DEG C. to avoid ignition of the silicon. Preferred chlorides are those of ammonia, potassium and lithium. 2 to 5 per cent. of the chloride catalyst may be employed and, in the case of ammonium chloride, it may be employed as a vapour. Preferably the reactants, silicon and chlorine, and the catalyst are fed to the top of a reactor operating at less than 200 DEG C. Reaction heat may be removed by cooling and local overheating may be prevented by diluting the chlorine with silicon tetrachloride, nitrogen or argon. The yield of higher homologues, trisilicon octachloride and tetrasilicon decachloride is favoured by employing lower temperatures.