Efficient and selective transformation of biomass-derived furfural with aliphatic alcohols catalyzed by a binary Cu-Ce oxide

The efficient transformation of furfural (FUR) with aliphatic alcohols to achieve the carbon-chain growth has been developed using a binary Cu-Ce oxide as the catalyst. In the presence of molecular oxygen, the tandem oxidative condensation of FUR with n -propanol is successfully performed, in which an 85.4% conversion of FUR in 95.3% selectivity of 3-(furan-2-yl-)-2-methylacryaldehyde was obtained. The effects of different Cu/Ce ratios and base additives were investigated in detail. As a result, it is found that the CuO-CeO 2 (1: 9) catalyst is optimal and potassium carbonate is a suitable additive. Next, the recycling of CuO-CeO 2 catalyst was tested and there is no obvious activity loss after being reused five times. Moreover, the oxidative condensation of FUR with various aliphatic alcohols including ethanol, isopropanol, n -butanol and n -hexanol was studied where the long chain alcoholic molecule hinders the proceeding of reaction. Finally, based on the experimental results and reaction phenomena, a possible mechanism for the oxidative condensation of FUR with n -propanol-O 2 is proposed.