Highly Selective Transfer Hydrogenation of 5-Hydroxymethylfurfural to 2,5-Bis(hydroxymethyl)furan over Copper Oxide/Magnesium Oxide Catalysts

Abstract

The production of 2,5-bis(hydroxymethyl)furan (BHMF) is of considerable scientific interest and strategic value for the development of novel biodegradable polyesters. In this study, a non-precious CuO/MgO catalyst was synthesized by a facile coprecipitation method and applied to the transfer hydrogenation of 5-hydroxymethylfurfural (HMF) under mild conditions. Using isopropanol (10 mL) as the hydrogen donor, efficient conversion of HMF was achieved within 4 h at 160 °C and 0.5 MPa N₂ over the 10% CuO/MgO catalyst, yielding BHMF with 90.5% selectivity. Comprehensive characterization by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, and N₂ adsorption-desorption analysis suggested a reaction mechanism consistent with the Meerwein–Ponndorf–Verley (MPV) reaction. Single-factor experiments were conducted to evaluate the effects of copper oxide loading, solvent type, catalyst dosage, reaction time, and temperature on the conversion of HMF and the selectivity of BHMF. Additionally, the selectivity of BHMF remained stable after using CuO/MgO for five cycles. These results provide a foundation for developing more efficient selective hydrogenation processes in the biomass industry.