Hydrodeoxygenation of lignin-derived phenolic compounds into aromatic hydrocarbons under low hydrogen pressure using molybdenum oxide as catalyst

Abstract

MoO3 catalyst was prepared by calcination using (NH4)6Mo7O24·4H2O as precursor and was characterized by XRD, XPS, H2-TPR and low temperature N2 adsorption. Hydrodeoxygenation of phenol was conducted to investigate the catalytic performance of MoO3 catalyst at lower H2 pressure. Effects of reaction temperature, reaction time and N2 partial pressure on the phenol conversion and product distribution were tested carefully. MoO3 catalyst was found to preferentially produce arenes with high selectivity, while at lengthened reaction time cyclohexane selectivity was increased gradually. Oxygen vacancy site of MoO3 (Mo5+) was deemed to be the active center in the hydrodeoxygenation of phenol, which accounts for the cleavage of CAR-OH to benzene. In addition, MoO3 catalyzed HDO reactions were further tested using different phenolic compounds as reactants. Experimental results suggest MoO3 catalyst can be widely applied in the conversion of diverse lignin-derived phenolic compounds conversion to aromatic hydrocarbons.