Selective oxidation of lignocellulosic biomass to formic acid and high-grade cellulose with tailor-made polyoxometalate catalysts
The main goal of this project was to identify and to optimize tailor-made polyoxometalate catalysts for a fractionated oxidation of lignocellulosic biomass (i.e. wood and residues from sugar or paper industries) to produce formic acid (FA) and high-grade cellulose for further processing i.e. in white biotechnology to bio-ethanol. Homogeneous vanadium precursor like sodium metavanadate and vanadyl sulfate as well as Keggin-type polyoxometalates (POMs) and more exotic structures like Anderson-, Wells-Dawson and Lindqvist type POMs have been screened for the desired catalytic performance. The most promising behaviour was found using the Lindqvist-type POM K5V3W3O19 showing for the first time in literature a selective oxidation of solely hemicellulose and lignin to formic acid while the cellulose fraction was untrapped. However, this could be only a first step for the project goal as little product yields could be achieved.