Patent ID: 7420075

Claim:
A process of preparing organohalosilanes having the general formula (I): R n H m SiX (4−n−m) (I) wherein R is a monovalent hydrocarbon group, X is a halogen atom, n is an integer of 1 to 3, m is an integer of 0 or 1, and the sum of n+m is 1 to 3, said method comprising charging a reactor with a contact mass comprising metallic silicon and a catalyst and feeding an organohalide-containing gas to the reactor, wherein the catalyst comprises 0.01 to 50 parts by weight (calculated as metallic tin) of tin or a tin compound as an active component per 100 parts by weight of the metallic silicon and 0 to 20 parts by weight of a co-catalyst selected from zinc, antimony, arsenic, and phosphorus and compounds and alloys thereof per 100 parts by weight of the metallic silicon, with the proviso that the amount of the co-catalyst is smaller than the amount of tin, and with the proviso that copper is included as an incidental impurity in the metallic silicon and the catalyst in an amount of 0 to less than 0.1% by weight based on the metallic silicon.