Highly selective oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran over an α-MnO2 catalyst

Selective oxidation of 5-hydroxymethylfurfural (HMF) to 2, 5-diformylfuran (DFF) with molecular oxygen is realized with an α-MnO 2 catalyst under mild conditions. In this work, α-MnO 2 exhibited the best performance among the samples examined. Meanwhile, solvent shows a significant effect on the product selectivity and isopropanol is found good for improving the selectivity of DFF. 93.2 % conversion of HMF was achieved at 140 °C for 4 h with 84.3 % selectivity of DFF. Moreover, α-MnO 2 catalyst keeps good reusability in recycling for five times. The reaction pathway indicated that the lattice oxygen species on α-MnO 2 is involved in the selective oxidation of hydroxyl group in HMF molecule.