Gas phase hydrogendysis of glycerol catalyzed by Cu/ZnO/MOx (MOx = Al2O3, TiO2, and ZrO2) catalysts

Cit/ZnO/MOx ( MOx = Al2O3, TiO2, and ZrO2) catalysts were prepared by the coprecipitation method. Crystal ZnO and amorphous Al2O3, TiO2, and ZrO2 presented in both calcined and reduced Cu/ZnO/MO2, catalysts. After reduction, CuO species were converted to metallic copper (Cu). The acidities of the Cu/ZnO/MOx catalysts were in an order of Cu/ZnO/Al2O3 > Cu/ZnO/ZrO2 > Cu/ZnO/TiO2 > Cu/ZnO. The catalytic activities of Cu/ZnO/MOx catalysts in the gas phase hydrogenolysis of glycerol were studied at 240-300 C under 0.1 MPa of H-2. The acid sites of CuanO/MOx, catalysts catalyzed the dehydration of glycerol and the metallic copper catalyzed the hydrogenation reactions. Cu/ZnO/TiO2 catalyst favored the formation of 1,3-propanediol and ethylene glycol with maximum selectivities of 10% and 37%, respectively, at high reaction temperatures. Cu/ZnO/Al2O3 and Cu/ZnO/ZrO2 catalysts exhibited good selectivity toward hydroxyacetone ranging from 81% to 40% at reaction temperatures of 240-300 degrees C, which were higher than those of Cu/ZnO and Cu/ZnO/TiO2 catalysts. The composition of Cu/ZnO/MO, catalysts significantly affected the product selectivity in the gas phase hydrogenolysis of glycerol. (C) 2011 Elsevier B.V. All rights reserved.