Cu/SiO2 Catalysts Prepared by Different Methods for Hydrogenolysis of Dimethyl Oxalate to Ethylene Glycol

Cu/SiO2 catalysts have been prepared by the chemisorption-hydrolysis (CH), ammonia evaporation (AE) and wetness impregnation (WI) methods, and evaluated in gas phase hydrogenolysis of dimethyl oxalate (DMO) to ethylene glycol (EG). The Cu/SiO2 catalyst prepared by the CH method showed the highest hydrogenolysis activity and selectivity to EG, giving an EG yield of 92.6%. Characterizations disclosed that Cu species were poorly dispersed on the catalyst prepared by the WI method, which accounts for its poor activity. CH and AE methods could well disperse Cu species, but the CH method resulted in higher Cu-0 surface area and comparable Cu+ surface area as compared to the AE method. As a result, the Cu/SiO2 catalyst prepared by the CH method exhibits the higher hydrogenolysis activity than that by the AE method.