Efficient Aerobic Oxidation of 5-Hydroxymethylfurfural to 2,5-Diformylfuran over Fe2O3-Promoted MnO2 Catalyst

It is challenging to effectively convert 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF), a flexible biobased buildingblock, over non-noble metal catalysts. In this contribution, Mn-Fe oxides were prepared and served as highly active catalysts for the selective oxidation of HMF to DFF. Among Mn-Fe oxides with varied Mn-Fe molar ratios, Mn6Fe1Ox showed the best catalytic activity and offered HMF conversion up to 97% with a DFF selectivity of 98% (110 degrees C, 5 h, and 1.5 MPa O-2). It is revealed that the introduction of alpha-Fe2O3 resulted in significant enhancement in the amount of catalytic active sites (Mn4+-O2- pairs) and their activity in Mn6Fe1Ox for the dehydrogenation of HMF to DFF. Mn6Fe1Ox also was a robust catalyst that could be successively used at least six times without substantial loss in its catalytic activity. Furthermore, a facile two-step process for the conversion of fructose to DFF with a yield up to 80% was developed by the integration of dehydration and oxidation over Amberlyst-15 and Mn6Fe1Ox, respectively.