Patent ID: 7521574

Claim:
A method for preparing a contact mass for use in the preparation of phenylchlorosilanes, comprising the steps of premixing metallic silicon and a tin compound selected from the group consisting of a tin halide, a tin nitrate, a tin sulfate, a tin organic acid salt, and a mixture thereof in a weight ratio that provides 0.1 to 50 parts by weight of metallic tin per 100 parts by weight of metallic silicon and 0 to 20 parts by weight of a co-catalyst, selected from the group consisting of zinc, antimony, arsenic, and phosphorus and compounds and alloys thereof, per 100 parts by weight of 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 0.05% by weight based on the metallic silicon, and heat treating the premix in an inert gas atmosphere at a temperature of from 300° C. to 600° C. for from 1 to 10 hours.