Catalytic Valorisation of D-Fructose and Alcohols Using Silica-PEI-Polyoxometalate Composites

Abstract

A nano-catalyst composed by polyoxometalates (POMs) ionically immobilized on polyethyleneimine (PEI) functionalized silica (SiO2-[PEIH]x[POM]) was used for the dehydration of D-fructose to 5-hydroxymethylfurfural (HMF) and its subsequent oxidation of HMF to 2,5-diformylfuran (DFF). The morphology and textural properties of silica supports, SBA-15 and Stöber nanoparticles, influenced the catalytic outcome. The SiO2-[PEIH]x[POM] demonstrated high thermal stability and exceptional catalytic activity in fructose transformation. Using DMSO as a solvent in a one-pot synthesis, we achieved an HMF yield of 95 % after 0.5 hours at 150 °C and a DFF yield of 69% after 20 hours, whereas HMF oxidation afforded 86 % yield of DFF at the same condition with considerable turnover number (TON) of 1720. These findings suggested that SiO2-[PEIH]x[POM] catalysts are promising candidates for the valorization of fructose into sustainable chemical sources.