1: 3,3,5,5-tetramethyl-3,5-disila-4-oxa-1,6-heptadiene With methanol; sulfuric acid T=5 - 10°C; 1 h; 2: orthosilicic acid tetramethyl ester T=5 - 10°C; 1.5 h; 3: With sulfuric acid; water more than 3 stages;

pyridine; lithium orthosilicate; sodium carbonate 0.5 h;