Hydrogenation in supercritical conditions catalyzed by palladium supported on modified activated carbon

Abstract

Biomass is expected to be a substitute for traditional fossil fuels because it is renewable and environmentally friendly. Bio-oil, as an important utilization of biomass, has a complex composition. Accordingly, it remains a great challenge for oxygenated compounds in bio-oil to be upgraded, especially for furfural. In this research, a highly active catalyst with 1 wt% palladium supported on activated carbon (Pd/AC) was prepared by impregnating Pd species on modified activated carbon, which was applied to furfural catalytic hydrogenation in super critical carbon dioxide (scCO₂). The conversion rate (79%) was higher than that obtained in toluene as solvent (60%). A selectivity of furfuralcohol and tetrahydrofurfuryl alcohol of up to 100% was achieved in scCO₂ conditions with no byproducts obtained. In contrast, the total selectivity was only 60% using ethanol as solvent. Meanwhile, the reaction conditions in the scCO₂ including hydrogen pressure and catalyst amount have been investigated. The Pd/AC catalysts were characterized by XRD, SEM, IR and BET techniques. A green solvent, and high activity and selectivity present real advantages of this method over other methods.