Cu-Mg-Zr/SiO₂ catalyst for the selective hydrogenation of ethylene carbonate to methanol and ethylene glycol

A Cu_x-Mg_y-Zr_z/SiO₂ catalyst with a total metal loading of 60 wt% prepared by a deposition-precipitation method was applied for the selective hydrogenation of ethylene carbonate to methanol and ethylene glycol in a fixed-bed reactor. As a result, the Cu₈-Mg₁-Zr_0.47/SiO₂ catalyst furnished 99% ethylene carbonate conversion with 85% selectivity to methanol and 99% selectivity to ethylene glycol under the optimized reaction conditions. Moreover, the Cu₈-Mg₁-Zr_0.47/SiO₂ catalyst also showed a good lifetime and neither the activity nor the selectivity decreased the during 208 h test. The reaction was found to depend sensitively on the Cu particle size, the surface acidity and the catalyst surface composition. The synergistic effect of balanced Cu⁰ and Cu⁺ sites was considered to play a critical role in attaining high yields of methanol and ethylene glycol. Boric oxide also had a positive effect on the hydrogenation of ethylene carbonate, affording higher selectivity to methanol under much milder conditions.