Abstract: The invention relates to copper-based catalysts, processes for their production and their use and to a process for the production of alkyl halosilanes in the presence of said catalysts.

Abstract: The process for producing alkylhalogenosilanes, which comprises reacting a physical mixture of silicon, a selenium or tellurium promoter and a copper catalyst with an alkyl halide.

Abstract: A metallurgical silicon is disclosed which contains substantially from 30 to 180 ppm of phosphorus comprised of a crystalline phase of primary silicon having a dissolved phosphorus content between 30 and 150 parts per million and intermetal phases whose global ratio is between 0.5 and 2%, wherein among the intermediary phases, the phase Si.sub.2 Al.sub.2 Ca does not exceed 0.3% of the total of the metallurgical silicon mass. The metallurgical silcon is used for the synthesis of alkyl or aryl halogenosilanes useful for the preparation of silicones.

Abstract: In the production of an organochlorosilane by reaction of silicon with at least one of an alkyl or aryl chloride in the presence of a copper catalyst, the improvement which comprises employing as the silicon fine-particle silicon containing surface-bound chlorine produced by contacting fine-particle silicon in reactive form with gaseous or liquid chlorine.

Abstract: Metallic silicon for the Rochow-Synthesis is reduced to particles measuring at least 5 mm in their smallest dimension and 15 mm in their largest dimension, cooling the silicon from a temperature of at least 700.degree. C. to at most 120.degree. C. within a maximum of 2 seconds, and then ground and reacted.

Abstract: A process for the preparation of alkyl halogenosilanes comprising reacting silicon with alkyl halide in the presence of a copper catalyst and promoter substances and phosphorous and phosphorous compounds in combination with indium or indium compounds or aluminum or aluminum compounds or a mixture of aluminum or aluminum compounds and indium or indium compounds.