Synthesis of SiCl₄ via the Chloride Salt-Catalyzed Reaction of Orthosilicates with SOCl₂

This paper details a method to chlorinate tetraalkyl orthosilicates in the presence of a catalyst using SOCl 2 as the chloride source/deoxygenating agent. Several inexpensive catalysts were screened, and it was found that soluble chloride salts performed better than Lewis base catalysts. The optimized reaction employed a widely used and commercially available soluble chloride salt catalyst (e.g., NBu 4 Cl, 0.4 equiv), 16 equiv of SOCl 2, and afforded quantitative yield of SiCl 4 after 3 h. As the bulk of the orthosilicate substrate increased, the yield of SiCl 4 decreased. A reaction mechanism has been proposed.