Selective aerobic oxidation of the 5-hydroxymethylfurfural to 2,5-furandicarboxylic acid over gold nanoparticles supported on graphitized carbon: Study on reaction pathways

The design of a stable and efficient catalyst is crucial to the creation of high-valued bio-based products, and the catalytic selective oxidation of 5-hydroxymethylfurfural (5-HMF) to 2, 5-furandicarboxylic acid (FDCA) has received increasing attention. Different loadings of Au supported on the graphitized carbon (GC) catalysts ( x wt%Au/GC ( x  = 0.7, 1.0, 1.3, 2.0 and 2.7)) were prepared and characterized via ICP-OES, N 2 adsorption-desorption, XRD, FT-IR, TG, XPS and TEM. Results show that 2.0 wt%Au/GC displays 97% selectivity of FDCA and a near 100% conversion of 5-HMF in water under 7 bar O 2 pressure for 6 h at 110 °C in the presence of NaOH, which also exhibits good cycling stability. The surface species of Au 0 are in favor of the formation of FDCA. In this work, different reaction parameters were explored to optimize the reaction condition. The intermediates and the reaction pathways were also proposed on the basis of the formation and degradation of esters via various characterizations.