Efficient conversion of glucose to 5-hydroxymethylfurfural using bifunctional partially hydroxylated AlF3

Partially hydroxylated AlF3 (denoted as AlF3) was synthesized by using a sol-gel method, and unambiguously characterized by FT-IR, XRD, NH3-TPD, SEM, TEM, N-2 adsorption-desorption, and FTIR (pyridine-adsorption) techniques. The resulting mesoporous material (AlF3) simultaneously bearing Lewis and Bronsted acid sites was efficient for producing 5-hydroxymethylfurfural (HMF) from glucose, and an optimized HMF yield of 57.3% at a glucose conversion of 95.5% was obtained within 10 h at 140 degrees C. The effects of reaction temperature, time, catalyst amount, solvent and substrate type, and the amount of Bronsted/Lewis acid sites on conversion of glucose to HMF were also investigated. The existence of both Lewis and Bronsted acid sites in AlF3 was found to play a key role in glucose-to-HMF conversion.