Base-free oxidation of 5-hydroxymethylfurfural to 2, 5-furan dicarboxylic acid over nitrogen-containing polymers supported Cu-doped MnO2 nanowires

Nitrogen-containing polymer-supported Cu-doped MnO 2 (Cu-MnO 2 @PDVTA) nanowires were prepared and their catalytic performances were evaluated via oxidation of biomass-derived 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA). The Cu-MnO 2 @PDVTA catalysts were characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, N 2 physical adsorption, transmission electron microscopy, and X-ray photoelectron spectroscopy. Both the Cu 2+ and MnO 2 nanoparticles were found to synergistically promote HMF oxidation to FDCA via 2,5-furandicarbaldehyde and 5-formyl-2-furancarboxylic acid intermediates. The Cu-MnO 2 @PDVTA-3 catalyst demonstrated the highest catalytic activity, providing FDCA with an excellent yield of 96.8% after 12 h at 80 °C. The time course of HMF oxidation revealed that oxidation of the hydroxyl group in HMF was easier than that of the aldehyde group. Cu-MnO 2 @PDVTA-3 could act as a reusable heterogeneous catalyst for HMF oxidation.