Glucose dehydration into HMF by Lewis acidic metal chlorides : development of a hetero-geneous MeCIx/ionic liquid/SBA-15 catalyst

The efficient utilization of cellulosic biomass is limited by the selective conversion of fructose, the dominant sugar in cellulose, to 5-Hydroxymethylfurfural (HMF). HMF is a platform chemical for the production ofuseful intermediates. It can be formed in homogeneous metal chloride/ionic liquid systems. In industrial scale processes a cheaper solvent for glucose delivery is required and heterogeneous catalysts have clear advantages. Therefore we developed a heterogeneous catalyst by successfully grafting the ionic liquid to the surface of ordered mesoporous SBA-15 and doping this catalyst with metal chlorides. The catalysts were characterized by XRD, N2 physisorption, TEM, 29Si CP-MAS NMR. Besides, EXAFS measurements were performed for metal chloride ionic liquid system and the heterogeneous catalyst. The Cr/IL/SBA- 15 catalyst showed 46% glucose conversion and 22% HMF yield at 150 °C after 3 h of reaction. Although the HMF yields are somewhat lower than the homogeneous case, the system is promising, especially when the replacement of the ionic liquid solvent with water is considered.