Design of composite micro/mesoporous molecular sieve catalysts*

Abstract

Abstract: Two series of composite micro/mesoporous materials with different contributions of micro-and mesoporosity were prepared by dealumination and recrystallization of mordenite zeolite. The materials were characterized by X-ray diffraction, infrared spectroscopy, 27 Al magic angle spinning (MAS) NMR, nitrogen adsorption-desorption, and temperatureprogrammed desorption of ammonia (TPD NH 3 ). Catalytic properties were studied in transalkylation of biphenyl with diisopropylbenzene. Both types of composite materials showed remarkably high activity, stability, and selectivity toward formation of diisopropylbiphenyls with respect to both pure microporous and mesoporous materials. The effect is due to high zeolitic acidity combined with improved accessibility of active sites and transport of bulky molecules provided by mesopores