Aerobic oxidation of 5-(hydroxymethyl)furfural into 2,5-diformylfuran catalyzed by starch supported aluminum nitrate

Al(NO3)3 immobilized on expanded corn starch catalyst (ECS-IL-Al(NO3)3) was prepared by silane-modified imidazolium ionic liquid reacting with expanded corn starch (ECS) and coordination of Al(NO3)3 with the imidazolium chloride grafted on the surface, as proved by FT-IR, NMR, SEM/EDS, and XPS. The catalytic activity of ECS-IL-Al(NO3)3 was evaluated in the 5-hydroxymethylfurfural (HMF) oxidation under mild conditions with 98% of 2,5-diformylfuran (DFF) production at 99% HMF conversion after 5 h at 50 °C, using molecular oxygen as the oxidant. Furthermore, this catalyst was found to exhibit excellent recyclability, making it an attractive catalytic system from economic and environmental points of view.