Silylation of water glass. I. Solvent extraction and trimethylsilylation of silicic acid

TLDR: In this article, a homogeneous trimethylsilylation of silicic acid in nonaqueous media was studied, and the silylation process consisted of three steps: acidification of sodium silicate, solvent extraction, and trimethylation.

Abstract: Homogeneous trimethylsilylation of silicic acid in nonaqueous media was studied. The silylation process consisted of three steps: acidification of sodium silicate, solvent extraction. and trimethylation of silicic acid. Sodium silicate was first acidified with dilute sulfuric acid to form silicic acid: extraction followed with hydrophilic organic solvents. The Silicic acid obtained was finally allowed to react with trimethylchlorosilane to give trimethylsilylates with molecular weights of 1000–12,000. Optimum conditions for each step have been intensively sought to achieve trimethylsilylates in high yield. The trimethylsilylates exhibited excellent thermal stability and surface properties, such as water repellency and antifoaming properties, comparable to those of conventional polydimethylsiloxanes.