Improving the production of furfural from cellulose catalytic pyrolysis using WO3/γ-Al2O3 composite oxides

Abstract

Furfural is one of the top valuable building block chemicals, the selective production of furfural from biomass has attracted increasing concerns in recent years. In this work, a novel method for the selective production of furfural through cellulose catalytic pyrolysis with WO3/γ-Al2O3 was reported, and the synergistic effect between γ-Al2O3 and WO3 was explored. Compared with cellulose pyrolysis alone, the addition of γ-Al2O3 improved the selectivity of furans and greatly inhibited the formation of sugars; while, WO3 addition promoted the formation of levoglucosenone. When (20–40%) WO3/γ-Al2O3 were added, the amount of sugars was further reduced, and the yields of furans (furfural and 2-methylfuran, in particular) were further increased at the same time. Under the optimum conditions (temperature = 600 °C, residence time = 15 s, and catalyst to cellulose mass ratio of 4), 30%WO3/γ-Al2O3 showed the best performance, and the selectivity and yield of furfural were improved by nearly 100% and 300%, respectively, as compared with cellulose pyrolysis alone. In addition, compared with γ-Al2O3, the addition of 30%WO3/γ-Al2O3 further increased the yield of furfural and 2-methylfuran to about 50% and 200%, respectively. The high selectivity and yields of furans with WO3/γ-Al2O3 addition might be due to that WO3 crystals in the composite promote the formation of levoglucosenone, which is further converted to additional furans through the Lewis acid sites of γ-Al2O3. The study may provide some meaningful advices for improving the production of furfural from green catalytic pyrolysis of cellulose.