Efficient conversion of xylan and rice husk to furfural over immobilized imidazolium acidic ionic liquids

In the present work, three immobilized imidazolium acidic ionic liquid catalysts (ImmHSO 4 -IL, ImmCH 3 SO 3 -IL and ImmH 2 PO 4 -IL) were prepared with silica as carrier and modified with H 2 SO 4 , CH 3 SO 3 H and H 3 PO 4 , which were used as catalysts in the production of furfural from xylan and rice husk. The characteristics of the synthesized catalysts were analyzed by various characterization techniques, and the effects of reaction conditions, including reaction solvent, reaction time, reaction temperature and the amount of catalyst on the yield of furfural were studied in detail. The results showed that the highest yield of furfural reached 72% and 74.6% when using xylan and rice husk as substrates, respectively, which is one of the best furfural yield among literature reports. In addition, the ImmHSO 4 -IL catalyst has excellent selectivity for hemicellulose in rice husk, and the catalyst has high catalytic activity after four cycles. Therefore, the application of ImmHSO 4 -IL catalyst provides a new approach for conversion biomass to furfural. Graphical abstract