Production of γ-Valerolactone from One-Pot Transformation of Biomass-Derived Carbohydrates Over Chitosan-Supported Ruthenium Catalyst Combined with Zeolite ZSM-5

It remains as a challenge to directly transform the biomass-derived C5 carbohydrates, such as furfural (FF) and its upstream product xylose and hemicellulose, to gamma-valerolactone (GVL), a versatile renewable chemical platform, due to various restrictions in the current synthetic strategies. Using formic acid as green hydrogen source, we synthesized the recyclable chitosan-Ru/PPh3 catalyst system, effective for both the hydrogenation of FF to furfuryl alcohol (FAL) and the reduction of levulinic acid (LA) or ethyl levulinate (EL) to GVL, affording up to 99 % product yields. The combination of chitosan-Ru/PPh3 with ZSM-5 could successfully achieve up to 79 % yield of GVL from one-pot conversion of FF under mild condition. Preliminary studies indicated that this method could also be applied to the direct conversion of biomass-derived C5 carbohydrates such as xylose and hemicellulose to GVL in 37 % or 30 % yield, respectively.