Water as Hydrogen Source for Highly Efficient Conversion of Biomass-Derived Levulinic Acid into γ-Valerolactone over Raney Ni Catalyst

Gamma (γ)-valerolactone (GVL) is a promising liquid for energy and carbon-based chemicals. Although many researches regarding the GVL synthesis from carbohydrate biomass, most of them involve the use of noble metals accompanying with the high-purity and high-pressure gaseous hydrogen, existing high cost in large-scale application and safety risk during the transportation and operation process. In this paper, the cheap metal Fe was employed as a reductant for splitting water to produce hydrogen under mild hydrothermal conditions, and commercial Raney Ni was used as a catalyst for in situ hydrogenation of biomass-derived levulinic acid (LA). More than 95% yield of GVL can be attained at 150 ^oC for 2 h and ~ 90% yield of GVL was also achieved at 100 ^oC by increasing the reaction time to 5 h. Furthermore, Raney Ni remains the stable catalytic activity after being recycled for 4 times at 150 ^oC. This work provides a safe and facile process for highly efficient hydrogenation of biomass-derived LA to GVL without precious metals.