Conversion of xylan, d-xylose and lignocellulosic biomass into furfural using AlCl3 as catalyst in ionic liquid

In order to define a new green catalytic pathway for the production of furfural, the catalyzed conversion of xylan into furfural in 1-butyl-3-methylimidazolium chloride was studied by using mineral acids and metal chlorides as catalysts under microwave irradiation. Amongst these catalysts, AlCl3 resulted in the highest furfural yield of 84.8% at 170 °C for 10 s. The effect of AlCl3 on the conversion efficiency of d-xylose and untreated lignocellulosic biomass was also investigated, the yields of furfural from corncob, grass and pine wood catalyzed by AlCl3 in [BMIM]Cl were in the range of 16–33%. [BMIM]Cl and AlCl3 could be recycled for four runs with stable catalytic activity. AlCl3 is less corrosive than mineral acids, and the use of ionic liquid as reaction medium will no longer generate toxic wastewater, thus this reaction system is more ecologically viable.