In‐Situ Investigations of Polyoxometalate‐Catalysed Biomass Oxidation to Formic Acid by Using Multinuclear High Resolution Flow NMR Spectroscopy

Abstract Biomass valorisation over polyoxometalate‐based (POM) catalysts is a promising strategy for green and sustainable chemistry. In order to further improve such processes e. g. by using different additives, a better understanding of the chemical influence of various additives on the catalyst is paramount. The main objective of this study is to gain a deeper understanding of the effects caused by various additives on the catalytically active vanadium species in the selective aerobic oxidation of carbohydrates to formic acid (esters). After carefully choosing a suitable model system, the oxidation of glycolaldehyde using the heteropolyacid H 5 PV 2 Mo 10 O 40 (HPA‐2) as a catalyst was studied in situ by Flow Nuclear magnetic resonance (FlowNMR) spectroscopy. These measurements allowed to identify the catalytically active isomer of the HPA‐2‐catalyst and to observe the influence of additives on the reaction kinetics in situ . These findings provide a good basis for further improving POM‐based catalytic aerobic oxidation of biomass.