Pd-Au Catalysts for the hydrogenation of levulinic acid to g-valerolactone at mild condition

It is well known that, nowadays, for a sustainable production of fuels, one of the most important approaches is the valorization of biomass residue. From the acid treatment of lignocellulosic materials, platform chemical levulinic acid (LA) can be easily obtained. LA can be further converted into many valuable chemicals. The catalytic hydrogenation of this acid leads to the formation of gamma-valerolactone (GVL). Recently, the effect of different supports, silica HMS and Ti doped silica HMS, on the catalytic performance of mono (Pd) and bimetallic (Pd-Au, Pd-Re) catalysts, containing 2 wt% of each metal, for the hydrogenation of levulinic acid in water was studied. In that case the strong reaction condition (T=160°C and P=150 bar) induced a synergic effect of Au and Ti with the consequent formation of a PdTi alloy responsible of the good performance of the catalyst. In this work, the effect of different support (SBA and Ti doped SBA) and milder reaction condition on the catalytic performance of Pd and Pd-Au catalysts for the hydrogenation of levulinic acid is investigated. The catalytic behavior of the materials is evaluated in terms of conversion of the starting levulinic acid and selectivity to gamma-valerolactone. The surface and structural properties of the catalysts are investigated by means of X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) performed on fresh and spent materials.