The “direct” synthesis of trialkoxysilanes: New data for understanding the processes of the copper-containing active sites formation during the activation of the initial silicon based contact mass

Direct reaction between silicon and methanol over Cu-based catalysts: investigation of active species and regeneration of CuCl catalyst

When a CuCl/Si mixture was pretreated at 200–240 °C in a N₂ atmosphere, trimethoxysilane was predominantly formed in the direct reaction of silicon with methanol. When the pretreatment temperatures were raised to 260–340 °C, tetramethoxysilane was favorably formed. The Cu_xSi_yCl_z species catalyzed the reaction between silicon and methanol to trimethoxysilane. Chlorination of the spent CuCl/Si mixture promoted the reaction between silicon and methanol to form both trimethoxysilane and tetramethoxysilane due to the recovery of the CuCl phase and the exposure of the metallic Cu⁰ phase. When Cu₂O, CuO, and Cu⁰ were used as the catalysts, tetramethoxysilane was formed as the main product.

Cu_xSi_yCl_z formed at a lower pretreatment temperature favored trimethoxysilane formation while chlorination of spent CuCl/Si mixture promoted the reaction.