Promotional effect of Mn doping on Ru/layered MCM-49 catalysts for the conversion of Levulinic acid to γ-Valerolactone

Selective hydrogenation of Levulinic acid (LA) to γ-Valerolactone (GVL) is an important reaction to produce high value-added chemicals and fuels but remains a big challenge. Herein we reported a Ru/zeolite catalyst with Mn promotion, which exhibited excellent catalytic performance (yield: 98%) towards LA to GVL. The intrinsic activity (TOF) also increased obviously with the Mn addition. The particle size of Ru gradually decreased with the increase of Mn loading and a strong interaction between Ru and support was observed for the Ru-Mn/MCM-49 catalyst. The addition of Mn not only offered a good dispersion of Ru species on MCM-49, but also increased the L/B ratio of the catalyst, thereby contributing to the high GVL selectivity. High dispersed Ru sites were the intrinsic active sites of the catalyst verified by the in-situ experimental studies. The dissociation of the reactants was significantly enhanced, resulting in higher catalytic activity.