The influence mechanism of solvent on the hydrogenation of dimethyl oxalate

Abstract

Abstract The hydrogenation of dimethyl oxalate (DMO) for the producing of C2-C4 alcohols with methanol as solvent was researched at the temperature of 270 °C to 310 °C. Ethylene glycol (EG) was the main product at low temperature and the selectivity of which was 61.9% at 230 °C. However, EG selectivity decreased sharply with the increase of temperature while ethanol became the main liquid products with the selectivity of 43.5% at 270 °C. It can be ascribed to a thorough hydrogenation of DMO at a high temperature. In addition, the promotion of Guerbet reaction led to the production of propanol and butanol. Simultaneously, the amount of gas products including CO, CO2 and dimethyl ether (DME) also increased, which became a competition factor in the conversion of DMO to liquid products including C2-C4 alcohols. The blank test was carried out with pure methanol as feedstock with and without Cu/SiO2 catalyst, which revealed that methanol was involved in the formation of gas products and higher alcohols on Cu-based catalyst, and the main gas product was CO.