The role of the ZnO promoter in the structural evolution of Cu2O in the Rochow-Müller reaction for dimethyldichlorosilane synthesis

Abstract

Zinc oxide (ZnO) is commonly used as a promoter in Cu-based catalysts for the Rochow-Müller reaction, which is used to produce organosilane monomers in the organosilicon industry. However, the impact of ZnO on the phase transformation of Cu-based catalysts during the Rochow-Müller reaction has not been fully revealed. In this work, we synthesized two ZnO-modified Cu₂O model catalysts by simple ball milling (Cu₂O-ZnO) and physical mixing (Cu₂O+ZnO) methods. The addition of ZnO enhanced catalytic properties, resulting in higher dimethyldichlorosilane (M2) selectivity and Si conversion compared to using the pure Cu₂O catalyst. The introduction of ZnO into Cu₂O enhanced the adsorption of methyl chloride (MeCl) on the Cu₂O surface, causing Cu₂O to transform into Cu and CuCl. Subsequently, CuCl reacted with active Si to form active Cu_xSi species. This work provides valuable insights into the roles of ZnO in Cu₂O-based catalysts and sheds light on their catalytic mechanism in the Rochow-Müller reaction.