Hydroisomerization of hexadecane over platinum supported on EU-1/ZSM-48 intergrowth zeolite catalysts

Abstract

A composite co-crystalline zeolite Eu-1/ZSM-48 was synthesized by a hydrothermal method. The composite materials consist of crystals with intergrowth between the EU-1 (EUO framework type) zeolite and ZSM-48 (MRE framework type) zeolite. The physicochemical properties of EU-1, ZSM-48 and EU-1/ZSM-48 were identified with respect to their crystallinity, textural parameters and acidity by means of X-ray diffraction, N₂ adsorption–desorption analysis, scanning electron microscopy, temperature-programmed desorption of ammonia and pyridine adsorption infrared spectroscopy. The catalytic performance of different composite zeolite loaded platinum-based catalysts was studied through the hydroisomerization of hexadecane to isohexadecane as a probe reaction under various reaction conditions. The results indicated that the best performance was obtained over EU-1/ZSM-48 even though EU-1 showed the highest conversion and ZSM-48 showed the highest selectivity. The catalytic performance of EU-1/ZSM-48-200 was significantly different from that of ZSM-48-200 which possessed the same bulk SiO₂/Al₂O₃. The catalytic performance of the EU-1/ZSM-48 intergrowth zeolite improved dramatically compared with the mechanical mixture of pure zeolites. The acidity of the intergrowth zeolite was favorable for the catalytic hydroisomerization of n-hexadecane.