Organosilane surfactant-assisted synthesis of mesoporous SSZ-39 zeolite with enhanced catalytic performance in the methanol-to-olefins reaction

SSZ-39 zeolite with AEI framework structure is a good catalyst candidate for the methanol-to-olefins(MTO)reaction.However,the diffusion limitation and coke formation often results in fast deactivation of the SSZ-39 zeolite catalyst.One solution for this challenge is to introduce mesoporosity in the SSZ-39 zeolite.Herein,we report the synthesis of mesoporous SSZ-39 zeolite using an organosilane surfactant,,-dimethyl--(3-(trimethoxysilyl)propyl)octan-1-aminium chloride,as a mesopore template and,-dimethyl--2,6-dimethylpiperidinium as a micropore template.The obtained zeolites were characterized by X-ray diffraction,N sorption,scanning electron microscopy,temperature programmed desorption of ammonia,and magic angle spinning nuclear magnetic resonance of Al.The results show that the mesoporous SSZ-39 zeolite has high crystallinity,meso/microporosity,high surface area,cuboid morphology,and abundant acidic sites.More importantly,this mesoporous SSZ-39 zeolite exhibits enhanced catalyst lifetime in the MTO reaction due to the presence of mesoporosity for fast mass transfer,compared with a conventional SSZ-39 zeolite without mesoporosity.