Features of the mechanochemical synthesis of methylmethoxysilanes from silicon and dimethyl carbonate in the presence of promoters†

This work presents the results of a study on the CuCl-catalyzed reaction of silicon with dimethyl carbonate (DMC) in a high-pressure mechanochemical reactor (HPMR) at 250 °C. The reaction was carried out in the presence of both single promoters (Al, Zn, Sn) and their various combinations. The best selectivity toward dimethyldimethoxysilane was obtained using Sn (70%) at a silicon conversion of 30%. The best performance for silicon conversion (73%) was achieved with the combined use of Zn and Sn. The selectivity toward dimethyldimethoxysilane in this case was 38%. The influence of the type and number of promoters, as well as the material of the grinding bodies (GBs) on the selectivity and conversion of silicon in its reaction with DMC were investigated. The liquid reaction products were characterized by GC, GC-MS, ¹H, ¹³C, ²⁹Si NMR spectroscopy. Spent contact masses after syntheses were investigated by PXRD, SEM-EDX and XPS.