Glucose conversion to 5-hydroxymethylfurfural with chromium exchanged bentonite and montmorillonite catalysts in different solvents

Synthesis of 5-hydroxymethylfurfural (HMF) was studied using Cr-montmorillonite and Cr-bentonite catalysts. Catalysts were characterized by Brunauer–Emmett–Teller surface area analyzer, X-ray diffraction (XRD), infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS). The effects of temperature and time on the conversion of glucose to HMF were investigated with different solvent-catalyst systems. HMF yield (45%) was obtained at 140 °C for 20 min using Cr-montmorillonite in 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) ionic liquid. The 62.6% HMF yield was efficiently achieved at 150 °C for 10 min in [BMIM]Cl using Cr-bentonite. Cr-bentonite catalyst has good reusable properties in dimethyl sulfoxide (DMSO). The 94% of catalytic efficiency was maintained at the end of fifth use in DMSO.