The Crystallization Process of MCM-49/ZSM-35 Composite Zeolites in a Mixed-Amine System

The crystallization process of MCM-49/ZSM-35 composite zeolites in the Na2O-SiO2-Al2O3-CHA (cyclohexamine)-HMI (hexamethyleneimine)-H2O system was investigated by X-ray diffraction. N-2 adsorption, scanning electron microscopy, and Fourier transform infrared spectroscopy The results showed that in the HMI-CHA system, pure phase MCM-49 was obtained first. then MCM-49/ZSM-35 composite zeolites were gradually formed with increasing ZSM-35 content upon the crystallization time, and finally pure phase ZSM-35 was produced Moreover, the formation of ZSM-35 zeolite was based on the consumption of MCM-49 zeolite in this mixed-amine system Key words: MCM-49. ZSM-35. composite zeolite, synthesis. crystallization process. cyclohexamine; hexamethyleneimine