Preparation and structure of [C₁₀H₉N]₂CuBr₂ and its catalytic activity in oxidative carbonylation of ethanol

The copper coordination compound [C₁₀H₉N]₂CuBr₂ was prepared by the reaction of 4-methylchinolin with copper bromide in ethanol solution. The compound was characterized with FTIR, EA, ICP-AES and XRD, and its catalytic performance in oxidative carbonylation of ethanol was investigated. The density functional theory (DFT) calculations were performed to analyze its structure, natural atomic charges and frontier orbital energy levels. The introduction of ligand could improve catalytic activity to prepare diethyl carbonate. The per pass conversion of ethanol could reach 21.5% under the reaction conditions of temperature 373 K, pressure 3.5 MPa, time 4 h and mass concentration of catalyst in ethanol 0.075 g·ml^-1. Reaction mechanism study showed that the compound had moderate stability, which benefited insertion of CO (the rate-controlling step) and formation of intermediate. Therefore, reaction activity was enhanced.