The reaction of dimethyldichlorosilane with polyorganosiloxanes derived from pseudowollastonite

The interaction of dimethyidichlorosilane with polyorganosiloxanes prepared by the trimethylsilylation of mineral silicates is catalysed by ferric chloride hexahydrate and results in the formation of higher molecular weight polyorganosiloxanes and also trimethylchlorosilane. The nature of the products and particularly the molecular weight depends on the relative amounts of reactants. It is also shown that during the course of the reaction a substantial proportion of the ferric chloride is reduced to ferrous.