Enhanced production of high octane oxygenates from glycerol etherification using the desilicated BEA zeolite

Abstract

BEA zeolites possessing different properties in terms of porosity and acidity have been applied for catalytic conversion of low value glycerol into high octane oxygenate useful for fuel applications. The properties of the materials have been characterized by X-ray diffraction (XRD), N2-sorption, Scanning/Tunneling Electron Microscopy (SEM/TEM), Temperature Programmed Desorption (TPD), FTIR spectroscopy and evaluated for their activity towards tert-butylation of glycerol. The desilication of Beta zeolite (BEA) resulted in the creation of ∼20nm range meso-pores responsible for a two-fold increase in the pore volume without any structural damage to the zeolite framework. The desilication method also resulted in increase of the strong acid sites measured by TPD. The desilicated BEA (DSBEA) zeolite with enhanced properties exhibited as high as 98% glycerol conversion with 99% selectivity to diesel miscible oxygenates i.e. mixture of di- and tri- ter-butyl glycerol (DTBG+TTBG). The results indicate that the space restrictions in the zeolite channels have been over ruled by the mesoporous BEA zeolite catalyst to produce high yields of TTBG. The DSBEA zeolite catalyst also exhibited stability in catalytic performance with the reaction time and reaction cycles.