Seed-Assisted Synthesis and Catalytic Performance of Nano-sized ZSM-5 Aggregates in a One-Step Crystallization Process  

作　　者：Ziyang Wang Yaquan Wang Chao Sun Aijuan Zhao Cui Wang Xu Zhang Jingjing Zhao Taotao Zhao Wenrong Liu Jiaxin Lu Shuhui Wu 

机构地区：[1]Key Laboratory for Green Chemical Technology of Ministry of Education,Tianjin 300072,China [2]School of Chemical Engineering and Technology,Tianjin University,Tianjin 300072,China

出　　处：《Transactions of Tianjin University》2020年第4期292-304,共13页天津大学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.21276183).

摘　　要：Hierarchical nano-sized ZSM-5 aggregates were successfully synthesized via a seed-assisted method in the presence of cetyltrimethylammonium bromide(CTAB)through a facile one-step crystallization process.Commercial ZSM-5 zeolites with a SiO2/Al2O3 ratio comparable to that of ZSM-5 products were treated with alkali and used as the seed particles.The influences of crystallization conditions were investigated,and the possible synthesis mechanism was proposed.ZSM-5 zeolites with diff erent amounts of CTAB added were characterized using many techniques and evaluated in toluene alkylation with methanol.The results showed that a trace amount of CTAB signifi cantly promoted the crystallization of ZSM-5 zeolite,with the morphology changing from hexagonal-shape crystals to uniform spherical aggregates.CTAB may act as the structure-directing agent and assemble the primary crystallites to generate hierarchical ZSM-5 aggregates.The ZSM-5 zeolite with the smallest primary particles of 50-80 nm exhibited large specific surface area,abundant mesopores,and the greatest microporosity.The hierarchical nano-sized ZSM-5 aggregate showed higher toluene conversion and a longer lifetime without compromising the selectivity to xylene and p-xylene in toluene alkylation with methanol.

关 键 词：Hierarchical ZSM-5 Nano-sized aggregates Seed-assisted CTAB Toluene alkylation with methanol 

分 类 号：O643.36[理学—物理化学] TB383.1[理学—化学]