Structure-Activity relationship and reaction mechanisms of the Cu/PSAC-Nx catalysts in the oxidation carbonylation of ethanol to diethyl carbonate

Abstract

Cu catalysts supported on nitrogen-doped carbon with ultra-high specific surface area (2726 m2⋅g−1) derived from peanut shells (PSAC-Nx) were fabricated and investigated in the oxidative carbonylation of ethanol to diethyl carbonate (DEC). The Cu/PSAC-Nx catalysts exhibited superior catalytic performance with a maximum STYDEC of 3371 mg·g−1·h−1, attributed to the higher surface Cu0 and Cu+ concentration. Both Cu0 and Cu+ acted as the active species that accelerated the activation of ethanol molecules and promoted the insertion of CO, respectively, in the DEC synthesis. Among the four by-products, diethoxyethane preferred to be generated at higher temperatures or extended reaction time, while acetaldehyde and ethyl acetate tended to be produced at the Cu2+ species and ethyl formate was inclined to be created at a higher oxygen fraction. This work provided theoretical and experimental guidance for the rational design of efficient catalysts and the optimization of reaction conditions for the ethanol oxidative carbonylation to DEC.