Hydrogenolysis of glycerol to 1,2-propanediol on copper core-porous silica shell-nanoparticles

Abstract

Glycerol hydrogenolysis to 1,2-propanediol (PDO) was investigated in methanol over copper core-porous silica shell-nanoparticles with a Cu/Si atomic ratio range of 1/8–2. These catalysts were prepared by coating silica onto the surface of chemically reduced Cu-polyvinylpyrrolidone colloids, and were characterized with TEM, nitrogen adsorption, XRD, H2-TPR and NH3-TPD. In the absence of externally added hydrogen, the catalyst with a Cu/Si atomic ratio of 1 exhibited the best PDO yield (72.8% at 200 °C), which was ascribed to its largest surface area. The intermediate-acetol-yield increased with increasing Cu/Si atomic ratio and reaction temperature. In the presence of externally added hydrogen, the catalyst with a Cu/Si atomic ratio of 2 had the best PDO yield (96.5% at 200 °C), which was ascribed to its greatest copper content and large pore size. The rate of glycerol disappearance exhibited first-order dependence on glycerol concentration. Under identical reaction conditions, Cu@SiO2 core-shell-catalysts with Cu/Si atomic ratios of 1 and 2 exhibited better performances than a commercial copper chromite catalyst.