초록 |
Herein, we presented highly selective hydrogenation of ketonic (>C=O) group in levulinic acid (LA) into 1,4-pentanediol (1,4-PDO) over ZnO-promoted Cu-Ni-H-ZSM-5 catalyst under mild reaction conditions (120 °C, 2.5 MPa and 2 h) in an aqueous medium. The 1,4-PDO selectivity was up to 93.7%. The presence of intermetallic Cu-Ni, Cu-Zn and Ni-Zn sites in the catalyst, which was confirmed by HAADF-STEM analysis, was found to be highly active sites for the reactant conversion. Not only this, the change in acid density of the catalyst proximate to the metal sites accelerated the reaction in the forward direction; the weak Lewis acid sites increased upon increasing the metal content, while both the moderate and strong acid sites decreased. The catalyst could be efficiently recycled and reused through simple treatments, offering above 90% LA conversions and high-yield 1,4-PDO in consecutive reactions. |