Selective oxidation of complex, water-insoluble biomass to formic acid using additives as reaction accelerators

The oxidation of complex, water-insoluble biomass to formic acid is reported using a Keggin-type polyoxometalate (H sub(5)PV sub(2)Mo sub(10 )O sub(40)) as the homogeneous catalyst, oxygen as the oxidant, water as the solvent and p-toluenesulfonic acid as the best additive. The reaction proceeds at 90 degree C and 30 bar O sub(2) and transforms feedstock like wood, waste paper, or even cyanobacteria to formic acid and CO sub(2) as the sole products. The reaction obtains up to 53% yield in formic acid for xylan as the feedstock within 24 h. Besides the role of the additive as a reaction promoter, the formic acid isolation and the recycling of catalyst and additive are demonstrated.