Chemicals from Biomass: Aerobic oxidation of 5-hydroxymethyl-2-furaldehyde into diformylfurane catalyzed by immobilized vanadyl-pyridine complexes

Introduction 5-Hydroxymethyl-2-furaldehyde (HMF), as diformylfurane precursor (DFF), is obtained from fructose or glucose dehydration. DFF is a versatile chemical, and there are numerous reports describing various applications as a monomer, as starting materials for the synthesis of pharmaceuticals and antifungal agents [1]. To date, few reports describe the use of air to oxidize (HMF) with heterogeneous catalysis [2,3]. Basic-type supports are known to be advantageous for the catalytic alcohol oxidation and, besides, metals redox activity (e.g. V, Cu, etc.) may be enhanced by pyridine ligands [4]. We present here the aerobic oxidation of HMF into DFF using catalysts based on metal (Cu,Pd and V)-pyridine coordination adducts, in the form of polymeric materials ((poly(4-vinylpyridine), PVP) and as silica immobilized complexes (organometallic complexes grafted onto organofunctionalized SBA-15 supports).