Keggin heteropolyacid catalysts: synthesis, heterogenization, and application in conversion of biomass-derived molecules

The present chapter discusses the synthesis, heterogenization, and application of Keggin heteropolyacid (HPA) to convert biorenewable resources to value-added chemicals and fuels. Thus, the application of pure heteropolyacid in oxidation, dehydration, esterification, etherification, and transesterification reactions has been discussed. Notably, pure HPAs face severe challenges due to low recyclability, low thermal stability, and high solubility in reaction media. Accordingly, different strategies for the heterogenization of heteropolyacid catalysts have been discussed. In particular, heterogenized HPAs have been categorized into two major classes, namely supported HPAs and substituted HPAs, followed by their application for a comprehensive range of reactions concerning to conversion of biomass-derived molecules.