Direct synthesis of tetraalkoxysilanes in a high-pressure mechanochemical reactor

We report the results of studies on the direct synthesis of tetraalkoxysilanes from alcohols and metallic silicon in a high-pressure mechanochemical reactor. The effect of the following factors on the process was considered: temperature (100-250 degrees C), amount of catalyst (0-20 wt%), type of catalyst, and type of the alcohol used in the synthesis. A silicon conversion of 90% with a selectivity of 94% with respect to a tetraalkoxysilane can be attained under optimal conditions. The studies showed that the temperature of the direct synthesis of alkoxysilanes was the lowest of the values reported to date (100 degrees C). Under these conditions, a silicon conversion of 77% and a selectivity of 98% with respect to a tetraalkoxysilane can be attained. It was shown that CuCl (20 wt%) exhibited the highest activity among copper-based catalysts, including CuF2, CuCl, CuBr, CuI, CuO, and Cu2O. In addition to MeOH, such alcohols as EtOH, n-BuOH, and EtO(CH2)(2)OH were used. The contact masses (CMs) sampled after 15 and 25 minutes and after reactions at 150, 200, and 250 degrees C were studied using SEM-EDX, PXRD, and XPS.

Automated summary

Studies on the direct synthesis of tetraalkoxysilanes from alcohols and metallic silicon in a high-pressure mechanochemical reactor showed that high silicon conversion and selectivity can be achieved under optimal conditions. CuCl exhibited the highest activity among copper-based catalysts, and different alcohols led to varied results in the synthesis process.