Vapor phase hydrogenolysis of glycerol to 1,2-propanediol over γ-Al2O3 supported copper or nickel monometallic and copper-nickel bimetallic catalysts

Vapor phase hydrogenolysis of glycerol was investigated over gamma-Al2O3 supported copper or nickel monometallic and copper-nickel bimetallic catalysts prepared by incipient wetness impregnation method. Catalytic results demonstrated that bimetallic catalysts were more selective to 1,2-propanediol (1,2-PDO) as compare to monometallic catalysts. Bimetallic copper-nickel phase promoted the selective hydrogenolysis of C-O bond and limited the cleavage of C-C bond which significantly reduced the formation of undesirable products. Very high 1,2-PDO yield of 88% at 98.5% glycerol conversion was achieved over 20 wt% Cu-Ni (1:1)/gamma-Al2O3 catalyst at very low hydrogen to glycerol mole ratio of 54.6 and at 220 degrees C and 0.75 MPa pressure. Superior performance of 20 wt% Cu-Ni (1:1)/gamma-Al2O3 catalyst was attributed to strong synergetic interaction due to the formation of copper-nickel bimetallic phase as confirmed by the XRD result. Times-on-stream study and the characterization results of the spent catalyst confirmed the structural stability of the copper-nickel bimetallic phase of 20 wt% Cu-Ni (1:1)/gamma-Al2O3 catalyst and negligible carbon deposition (0.03 mmol carbon gcat(-1) h(-1)) on the catalyst after prolonged contact under hydrogen environment. (C) 2016 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.