Promoted role of Cu(NO3)2 on aerobic oxidation of 5-hydroxymethylfurfural to 2,5-diformylfuran over VOSO4

Abstract The promoted effect of Cu(NO 3 ) 2 on aerobic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) catalyzed by VOSO 4 in acetonitrile was intensively investigated. It was revealed that Cu(NO 3 ) 2 facilitated the activation of VOSO 4 to generate active V 5+ species via the generation of NO x gas. The high DFF selectivity is ascribed to Cu 2+ cation which can effectively prohibit oxidative C C bond cleavage reaction of HMF and prevent radical reaction of DFF to humins. In addition, the polarity of solvent plays a great role on high selectivity of DFF.