Niobium exchanged tungstophosphoric acid supported on titania catalysts for selective synthesis of 5-ethoxymethylfurfural from fructose

Abstract Various niobium contained tungstophosphoric acid (NbTPA) supported on titania catalysts were prepared and investigated their activity for selective synthesis of 5-ethoxymethylfurfural (EMF) from fructose in ethanol/THF solvent system. Physico-chemical properties of the catalysts were assessed by different spectroscopic approaches like X-ray diffraction, Laser Raman, BET-surface area, FT-IR, pyridine adsorbed FT-IR and temperature programmed desorption of ammonia. The results of characterization direct the existence of firm Keggin ion structure of Nb exchanged TPA and its well dispersed state on support. Lewis acidic sites were induced with the existence of Nb ions. The catalytic activity was interrelated to the catalyst acidity which was liable on the number of Nb ions present in TPA and the amount of NbxTPA supported on TiO2. Among all catalysts 20wt% Nb0.4TPA/TiO2 catalyst showed best catalytic performance towards EMF with a yield of 76% at 130 οC after 6 h. The catalyst is recyclable without any depletion of activity.