Aerobic oxidation of 5-hydroxylmethylfurfural with homogeneous and nanoparticulate catalysts

The aerobic oxidation of 5-hydroxymethylfurfural (HMF) with homogeneous Co(OAc)(2)/Zn(OAc)(2)/Br(-), and heterogeneous Au-TiO(2) and Au-CeO(2) nanoparticulate catalysts was carried out in acetic acid with and without a trifluoroacetic acid (HTFA) additive. The selectivity of the oxidation products, 2,5-furandicarboxylic acid (FDCA) and 5-formyl-2-furancarboxylic acid (FFCA), improved in the presence of the HTFA (1 wt%) additive. The homogeneous oxidation catalyst gave higher selectivity for FDCA (60% yield) under 1 atm of O(2) at 90 degrees C while Au-TiO(2) afforded 80% FFCA under the same conditions.