Conversion of glycerol to dihydroxyacetone over Au catalysts on various supports

Abstract

AbstractBACKGROUNDGlycerol, which is a coproduct of biodiesel production, has been identified as a key platform compound for producing various valuable chemicals. The selective catalytic oxidation of glycerol to dihydroxyacetone is very attractive.RESULTSA series of Au catalysts supported on metallic oxides, i.e. ZnO, CuO, Al2O3, Fe2O3 and NiO, were studied for selective catalytic oxidation of glycerol to dihydroxyacetone under base‐free conditions. Among the catalysts, Au/CuO showed the best catalytic activity (glycerol conversion of 89% and dihydroxyacetone selectivity of 82.6% at 80 °C under 10 bar of O2), followed by Au/ZnO ≫ Au/NiO > Au/Al2O3 ≈ Au/CuO‐SD ≈ Au/Fe2O3. The catalytic behaviors of these supported Au catalysts varied depending on the Au particle size, Au oxidation state, Au–support interactions and lattice oxygen reducibility.CONCLUSIONThe main reasons for the high catalytic activity of Au/CuO are as follows. Firstly, the catalyst has small metallic Au particles, which are more active in cleavage of the secondary CH bond in glycerol molecules. Secondly, the interactions between Au and CuO facilitate lattice oxygen reduction, and this increases oxygen mobility, which may promote regeneration of Au–support perimeter active sites by gaseous oxygen. © 2019 Society of Chemical Industry