Palladium and carbon synergistically catalyzed room-temperature hydrodeoxygenation (HDO) of vanillyl alcohol – A typical lignin model molecule

Vanillyl alcohol, which is made up of an aromatic ring , an alcoholic hydroxyl group, a phenolic hydroxyl group and a methoxy group, was selected as the model molecule of lignin. Various carbon materials supported Pd catalysts were chosen to catalyze the HDO of vanillyl alcohol. The catalysts were characterized via TEM, TPD, XRD, XPS and CO-chemisorption. It was found that different carbon materials could obviously influence the particle sizes, dispersion and distribution of Pd or PdO particles. Palladium and carbon can synergistically catalyze the room-temperature HDO of vanillyl alcohol even at room temperature, and the carboxyl group was found to be the effective active acid site during the reaction. Possible reaction mechanism was also proposed. The existence of the effective active acid sites on the carbon supports could obviously lower the reaction temperature without decreasing the selectivity, as a result, making the production of renewable fuels by HDO much more economically feasible, which is of much importance.