From C5 to C7–11: Selective Carbon-Chain Increasing via Copper-Mediated Aerobic Oxidative Condensation of Biomass-Derived Furfural and Straight-Chain Alcohols

Abstract

The selective carbon-chain increasing from C5 to C7–11 was achieved through the aerobic oxidative condensation of biomass-derived furfural (FUR) and straight-chain alcohols with the Cu2O-LiOH catalytic system. In the case of the reaction of FUR with n-butanol, a 97.1% conversion of FUR and a 95.4% selectivity of 2-(furan-2-ylmethylene)butanal were attained under 0.3 MPa of O2 at 60 °C for 4 h. Moerover, the aerobic oxidative condensation of FUR with ethanol, n-propanol, n-pentanol, or n-hexanol was also successfully performed in the presence of the Cu2O-LiOH catalytic system. Further investigations revealed that the synergistic effect between Cu2O and LiOH is responsible for these aerobic oxidation condensation processes. Relying on the results of control experiments and catalytic principles, a possible reaction mechanism is proposed for the selective oxidation condensation of FUR with n-butanol in the presence of molecular oxygen.