Hydroxyapatite Supported Manganese Oxide as a Heterogeneous Catalyst for the Synthesis of 2, 5-Diformylfuran

A series of hydroxyapatite (HAP) supports with different Ca/P ratios were synthesized to prepare the MnO x /HAP catalysts. A MnO x /HAP catalyst showed highly efficient conversion of 5-hydroxymethylfurfural (HMF) into 2, 5-diformylfuran (DFF) in toluene solvent under no-alkali condition. 86.4% conversion of HMF with 90.9% selectivity of DFF at 120 °C for 12 h under 1.0 MPa O 2 over the MnO x /HAP-10.0-400 were obtained. The redox of Mn 4+ /Mn 3+ improved the oxidation of 5-HMF to DFF by the lattice oxygen, and the lattice oxygen was replenished by adsorbing O 2 molecules. The reusability tests were found the catalyst could be reused up to four cycles without notable loss of catalytic activity. The MnO x /HAP-10.0-400 was a stable and reusable material for further industrial exploration of DFF in an environmentally friendly way. Graphical Abstract