| 摘要 |
The invention relates to a novel catalytic system and method for the preparation of alkylhalogenosilanes by reacting alkyl halide with a contact mass comprising silicon and a catalytic system consisting of (a) metallic copper or a copper-based compound and (ss) a promoter assembly. The inventive method can be used to obtain, for example, a mean activity value, dialkyldihalogenosilane selectivity and a weight content of heavy by-products having improved values in relation to those recorded with the best hitherto-known catalytic systems. According to the invention, the promoter assembly (ss) comprises: between 10 and 500 ppm (calculated by weight of metal in relation to the mass of silicon used) of an additive ss1 which is selected from tin, a tin-based compound and a mixture of said species; between 0.01 and 2 % (calculated by weight of metal in relation to the mass of silicon used) of an additive ss2 which is selected from caesium, potassium and rubidium, a compound based on the aforementioned alkali metal and a mixture of said species; and between 50 and 3000 ppm (calculated by weight of elemental phosphorus in relation to the mass of silicon used) of an additive ss3 which is selected from phosphorus, a phosphorus-based compound and a mixture of said species. |
