Synthesis and characterization of MCM-49/ZSM-35 composite zeolites in the hexamethyleneimine and cyclohexamine system

A novel route for synthesis of MCM-49/ZSM-35 composite zeolites with different compositions in a mixed amine system containing hexamethyleneimine (HMI) and cyclohexamine (CHA) has been developed. Furthermore, both MCM-49 zeolite and ZSM-35 zeolite can be successfully synthesized by adjusting the synthesis conditions in the same system. Especially, the MCM-49/ZSM-35 composites with more content of ZSM-35 zeolite can be produced under conditions of larger CHA/HMI molar ratio, higher Na2O/Al2O3 molar ratio and longer crystallization time. The structure characterization, acid distribution and morphology of the MCM-49/ZSM-35 composite zeolites are characterized by X-ray diffraction, N-2 adsorption isotherms, NH3-TPD, scanning electron microscopy as well as Hp-Xe-129 NMR technology. These characterizations give obvious different pore structure of the MCM-49/ZSM-35 composite zeolites from the mechanical mixing counterpart. (C) 2009 Elsevier Inc. All rights reserved.