Microwave-assisted dehydration of fructose and inulin to HMFcatalyzed by niobium and zirconium phosphate catalysts

t5-Hydroxymethyl-2-furaldehyde (HMF) is a key bio-based platform for the production of renewablemonomers and bio-fuels. However, most of its syntheses are carried out under not sustainable con-ditions. In this work, the production of HMF from fructose and inulin was investigated following theGreen Chemistry principles, adopting aqueous medium, appreciable substrate concentration (10 wt%),low loading of heterogeneous acid catalyst (niobium or zirconium phosphate) and microwave heating.Both the catalysts resulted very active and promising, in particular zirconium phosphate and the per-formances were related to their different acid characteristics. The optimization of HMF synthesis withzirconium phosphate was also supported by a statistical modelling, which shows that the highest yieldto HMF (about 40 mol%) is ascertained at high temperature (190◦C) and short reaction time (8 min). Thecatalysts resulted recyclable maintaining their starting activity almost unchanged.