One-pot synthesis of 2,5-diformylfuran from fructose using a magnetic bi-functional catalyst

Abstract

A magnetic bi-functional WO₃HO-VO(salten)-SiO₂@Fe₃O₄ nanocatalyst was prepared to directly synthesize 2,5-diformylfuran (2,5-DFF) from fructose. The chlorosilylated SiO₂@Fe₃O₄ (Cl-SiO₂@Fe₃O₄) nanoparticles served as the platform for the two functionalities. Tungstic acid was generated via protonation of sodium tungstate, which was directly attached on the platform via nucleophilic –Cl displacement. Meanwhile, oxovanadium was complexed with a salten ligand which was functionalized on the Cl-SiO₂@Fe₃O₄. Characterization results confirmed the successful preparation of the WO₃HO-VO(salten)-SiO₂@Fe₃O₄ nanocatalyst. Under the optimal one-pot system, tungstic acid-mediated fructose dehydration afforded 82% 5-hydroxymethylfurfural (5-HMF) in 1 h. Upon co-oxidant H₂O₂ addition, in situ 5-HMF oxidation by the activated oxoperoxovanadium species produced 71% of 2,5-DFF after 15 h under ambient air. The stability of 5-HMF formation was found critical to 2,5-DFF production. Aside from the catalytic efficiency and process simplicity, the WO₃HO-VO(salten)-SiO₂@Fe₃O₄ nanocatalyst was readily retrieved magnetically and re-used multiple times with marginal losses in its activity.