One-pot DFF preparation method by HMF oxidation over Ru/MnO₂ catalyst and HFM from fructose dehydration.

Due to the depletion of traditional fossil resources and the increasing environmental problems, the utilization of sustainable biomass resources has become imperative. The selective oxidation of biomass-derived 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) has attracted much attention in recent years. However, the large-scale production of DFF remains a challenge given the low dosage of HMF in previous research. In this contribution, a desirable DFF yield of 90.5% is obtained from concentrated HMF (130 °C, 2.0 MPa oxygen, 8 h) over the prepared Ru/MnO₂ catalyst with abundant oxygen vacancies (O _V). The Ru/MnO₂ catalyst with high O _V exhibits a weak MnO bond intensity resulting in high lattice oxygen (O _L) reactivity, which promotes a high catalytic activity of HMF oxidation. Reusability studies show that the Ru/MnO₂ catalyst is stable and reusable. Furthermore, the direct production of DFF from fructose is also successfully realized via two consecutive steps, leading to a cost-efficient oxidation of HMF solution and facilitating the industrial production of DFF. This research provides profound insights into the selective oxidation of HMF to DFF, thereby fostering further investigations into the conversion of fructose into high-value chemicals.