Catalytic Conversion of Xylose to Furfural Using AlCl3-Dominant Catalysts in a Homogeneous System

A feasible and environmental-friendly approach was developed for the dehydration of xylose into furfural using AlCl3-dominant catalysts in a homogeneous DMSO/H2O system. Results showed that the paired chlorides (AlCl3/KCl) in the molar fraction (χAlCl3 ) of 0.6 displayed the better catalytic performance than the single AlCl3 and the other paired chlorides. The influences of catalyst amount, reaction temperatures as well as xylose concentration on the dehydration of xylose into furfural were studied. The effects of co-solvents (DMF, DMI, DMAC and NMP) on the production of furfural were also investigated. DMSO exhibited the better enhancement effect and the desirable DMSO/water volume ratio was 5:5, indicating DMSO could efficiently suppress the side reaction and enhance the selectivity. The maximum furfural yield of 43.6% with xylose conversion of 97.9% and the selectivity of 44.6% was achieved at 170°C for 2 h with a total catalyst/xylose molar ratio of 0.5 at the solid to liquid ratio of 1:10.