Selective synthesis of triphenoxysilane by the reaction of metallic silicon with phenol using copper(I) chloride as the catalyst

Article abstract of DOI:10.1016/0022-328X(95)06075-8

When copper(1) chloride was used as a catalyst in the reaction of silicon with phenol, a high selectivity for triphenoxysilane (HSi(OPh)₃) (94%) was obtained, the other product being tetraphenoxysilane (Si(OPh)₄). Addition of a small amount of propyl chloride to the feed for poisoning metallic copper enhanced the selectivity for HSi(OPh)₃ without affecting the rate of silicon consumption. This result indicates that HSi(OPh)₃ is an exclusive primary product and that Si(OPh)₄ is formed by the secondary reaction between HSi(OPh)₃ and phenol. The reaction mechanism involving surface silylene intermediate is proposed for the formation of HSi(OPh)₃ as the sole primary product. The intermediacy of surface silylene was confirmed by adding ethylene in the silicon-phenol reaction to give rise to the trapped product ethyldiphenoxysilane, obtained in a 5.8% selectivity.