238 Producing Fuels and Fine Chemicals from Biomass Using Nanomaterials
Heterogeneous catalysts can also be used in the oxidation of HMF to FDCA with
molecular oxygen. Supported platinum catalysts were rst used in the presence of base,
resulting in near quantitative FDCA yields. Recently, two examples were reported using
supported gold catalysts for aqueous HMF oxidation. Gorbanev et al. demonstrated that
Au/TiO
2
could oxidize HMF into FDCA in 71% yield at near-room temperature
54
and
Casanova et al. showed that Au/CeO
2
was even more active and selective.
55
However,
it should be noted that these noble catalyst systems all require at least stoichiometric
amounts of base to keep the FDCA formed in aqueous solution as the di-alkaline salt
56