Heterogeneous Cr-zeolites (USY and Beta) for the conversion of glucose and cellulose to 5-hydroxymethylfurfural (HMF)

For the first time, the heterogeneous calcined forms of chromium loaded USY, ZSM-5 and Beta zeolites were studied for the synthesis of HMF from glucose and cellulose in different solvents such as 1-butyl-3-methylimidazolium chloride (BMIMCl) and dimethyl sulfoxide (DMSO). Catalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, inductive coupling plasma-mass spectrometry and temperature programmed desorption (NH3-TPD). It was found that calcined forms of chromium-zeolites provide better HMF yield in (BMIMCl) ionic liquid than chromium-free zeolites. The 58.8% and 54.5% HMF yields from glucose and 34.1% and 34.3% HMF yields from cellulose were obtained at 130 degrees C after 60 min in BMIMCl ionic liquid with Cr-Beta (SiO2/Al2O3 = 28) and Cr-USY (SiO2/Al2O3 = 6) zeolites, respectively. 35% HMF yield was achieved with heterogeneous Cr-USY (SiO2/Al2O3 = 6) zeolite at 160 degrees C after 90 min in DMSO. However, HMF yield from cellulose was not observed in DMSO. Although chromium leaching from catalyst occurred in BMIMCI solvent, no loss of catalytic activity and no chromium leaching from catalyst was observed in DMSO for five times recycling reactions. It can be said that DMSO is highly suitable solvent for easily separable heterogeneous Cr-USY catalyst for glucose to HMF conversion.