Enhanced selective aerobic oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran using Mn-enriched MgSnO3 polymetallic catalyst

Catalytic oxidation of 5-Hydroxymethylfurfural (HMF) feedstock to value-added chemical 2,5-diformylfuran (DFF) is of great importance in biomass valorization. However, it is still challenging to develop non-noble metal-based catalysts for high selectivity of DFF due to the coexistence of other undesired derivatives. In this study, Mn x Mg 1-x SnO 3 was prepared by Mn incorporating into the crystalline lattice of MgSnO 3 , triggering synergetic catalysis for selective aerobic oxidation of HMF to DFF. Among polymetallic oxides with varying Mn-Mg molar ratios, Mn 0.67 Mg 0.33 SnO 3 (Mn/Mg ratio = 2:1) exhibited the best catalytic activity with DFF yield of 80.6 % and selectivity of 87.5 % at 160 °C for 6 h. It is revealed by various characterization analysis that Mn species in Mn 0.67 Mg 0.33 SnO 3 could not only act as active sites directly but also promote the transformation of oxygen into singlet oxygen for HMF oxidation. Furthermore, the used Mn 0.67 Mg 0.33 SnO 3 catalyst could be successfully reactivated through a straightforward two-step regeneration method involving impregnation followed by calcination, demonstrating remarkable stability.