Synthesis and Catalytic Reactivity of MCM-22/ZSM-35 Composites for Olefin Aromatization

A series of MCM-22/ZSM-35 composites has been hydrothermally synthesized and characterized by XRD, SEM, particle size distribution analysis, N₂ adsorption and NH₃-TPD techniques. Pulse and continuous flow reactions were carried out to evaluate the catalytic performances of these composites in aromatization of olefins, respectively. It was found that MCM-22/ZSM-35 composites could be rapidly crystallized at 174 °C with an optimal gel composition of SiO₂/Al₂O₃=25, Na₂O/SiO₂=0.11, HMI/SiO₂=0.35, and H₂O/SiO₂=45 (molar ratio), of which the weight ratio of ZSM-35 zeolite in the composite relied on the crystallization time. The coexistence of MCM-22 and ZSM-35 in the composite (MCM-22/ZSM-35=45/55 wt/wt) was observed to exert a notable synergistic effect on the aromatization ability for butene conversion and FCC gasoline updating, possibly due to the intergrowth of some MCM-22 and ZSM-35 layers.