Direct synthesis of 2,5-diformylfuran from carbohydrates via carbonizing polyoxometalate based mesoporous poly(ionic liquid)

A promising atom-effective heterogeneous catalyst derived from the partial carbonization of polyoxometalate based mesoporous poly(ionic liquid) was constructed for the direct (one-pot and one-step) conversion of carbohydrates into 2,5-diformylfuran (DFF). The carbon precursor was synthesized through the free radical copolymerization of carboxylic acid functional ionic liquid and divinyl benzene, followed by the ion-exchange with heteropolyacid H₅PMo₁₀V₂O₄₀ to introduce heteropolyanions. Partial carbonization dramatically enhanced the acid and oxidation properties, rendering the greatly strengthened activity in both the degradation of fructose into 5-hydroxymethylfurfural (HMF) and oxidation of HMF into DFF. As a result, the catalyst exhibited remarkable performance in the direct synthesis of DFF from fructose in a one-pot and one-step reaction, offering a high yield of 87.3% and a maximum turnover number (TON) of 77.7. The catalyst was facilely recovered and reused without apparent deactivation. The one-pot and one-step conversion of glucose into DFF reached the highest yield of 51.2% so far. Other carbohydrates such as inulin and sucrose were also effectively transformed into DFF, displaying good substrate compatibility.