Highly selective aromatic ring hydrogenation of lignin-derived compounds over macroporous Ru/Nb2O5 with the lost acidity at room temperature

Abstract

Selective aromatic ring hydrogenation is an important process for the valorization of lignin and designing the high active and selective catalyst is still a challenge. At present, it is reported that such catalysts generally have some shortcomings including strict reaction conditions, complicated catalyst preparation and low reaction efficiency. Herein, Ru/Nb2O5 catalyst with the macropore structure prepared by an incipient wetness impregnation method could effectively promote the aromatic rings hydrogenation of various lignin-derived compounds under extremely mild condition (30 °C). The resulting aliphatic compounds with the high yield provided abundant raw materials for the production of fine chemicals and biofuels. In this case, further experiments revealed that it was H2 rather than solvents provided the only hydrogen source. A relatively low bond energy of Ru0 in Ru/Nb2O5 promoted the formation of active hydrogen from H2. Due to the acid loss of Ru/Nb2O5 catalyst, the hydrodeoxygenation reaction did not occur. Moreover, the catalyst was investigated under different influence parameters in order to obtain the optimal reaction conditions (30 °C, 3 MPa H2). The application of Ru/Nb2O5 catalyst may provide a promising approach to the value-added utilization of lignin-derived fragments.