The influence mechanism of solvent on the hydrogenation of dimethyl oxalate

The hydrogenation of dimethyl oxalate (DMO) for the producing of C2-C4 alcohols with methanol as solvent was researched at the temperature of 270℃ to 310℃. Ethylene glycol (EG) was the main product at low temperature and the selectivity of which was 61.9% at 230℃. 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℃. 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.