The Use of WO3-ZSM-5 Zeolites in the Dehydration of Monosaccharides

Abstract

In this work, a procedure was developed for the synthesis of WO3-containing catalysts based on zeolites of the ZSM-5 type. Zeolites with different Si/Al ratios and different numbers of acid sites were used: ZSM-5-CVM, ZSM-5-CVN and ZSM-5-Acros. The synthesized catalysts were characterized and tested in the reaction of the conversion of fructose and glucose to 5-hydroxymethylfurfural (5-HMF) and levulinic acid (LA). It was shown that the introduction of tungsten (VI) oxide into the composition of ZSM-5 leads to a noticeable increase in the number of active acid sites on the catalyst surface, which plays an important role in the reaction. In particular, the total concentration of weak and strong Bronsted acid centres for ZSM-5-Acros was 0.057 mmol/g; after the modification of zeolite WO3, the concentration of acid sites increased to 0.575 mmol/g. As a result, the activity of the catalysts in the reaction of dehydration of monosaccharides and rehydration of 5-HMF increased sharply. The results of the study show the promise of using zeolites of the ZSM-5 type, modified with tungsten oxide (VI), in the conversion of biomass to platform chemicals.