Seed-assisted and OSDA-free synthesis of H-mordenite zeolites for efficient production of 5-hydroxymethylfurfural from glucose

In this study, the mordenite (MOR) zeolite is synthesized using a seed-assisted and template-free method and tested for glucose dehydration to 5-hydroxymethylfurfural (5-HMF). The synthesized zeolites are characterized by using X-Ray diffraction (XRD), N-2-sorption, Field Emission Scanning Electron Microscopy (FESEM), Pyridine-FTIR, Al-27 NMR and Thermogravimetric analysis. The mesoporosity has been introduced in the zeolite by the aging and/or with higher SiO2/Al2O3 ratio. Colloidal silica (CS) as a precursor in combination with aging resulted in a unidirectional growth of the crystals, as evidenced by FESEM images and XRD. The MOR synthesized with CS as silica precursor under 12 h aging showed the best activity giving a 5-HMF yield of 66% (selectivity 87%) with a glucose conversion of 76% at 180 degrees C for 1 h. Mesoporosity and the optimum number of Lewis and Bronsted acid sites of the MOR played a key role in obtaining the best activity.