等级孔微孔-介孔 Fe₂O₃/ZSM-5 中空分子筛催化材料的制备及催化苄基化性能

As a kind of efficient and environment friendly solid catalyst，ZSM-5 zeolite shows extremely uniform pore structure，excellent shape selectivity，great catalytic activity and superb hydrothermal stability，which has already been used in plenty of fields like petroleum catalytic cracking，fine-chemicals processing and environmental protection. However，its simplex microporous structure severely reduces the diffusion of guest molecules，which results in a great limitation of aromatic alkylation reaction in which macromolecules participate. In this paper，through a method of etching ZSM-5 zeolite with NaOH/TPAOH（tetrapropylammonium hydroxide）mixed alkali，a hierarchical micro-/mesoporous ZSM-5 catalyst with high crystallinity and abundant specific surface area was prepared. This special hierarchical structure can not only maintain the great hydrothermal stability and plentiful active centers of microporous ZSM-5，but also promote the diffusion of reactants and products with the introduction of mesopores. As a result，the conversion of m-trimethylbenzene benzylation increased 3.8 times. In addition，a bifunc⁃ tional hierarchical micro-/mesoporous Fe₂O₃/ZSM-5 hollow catalyst was developed by loading Fe on the hierarchical microporous- mesoporous ZSM-5 hollow catalyst mentioned above，which exhibited excellent catalytic performance in the benzylation reaction of benzene，and the conversion，selectivity and percent yield reached 98.3%，81.6% and 80.2% while Fe loading was 6.67%（mass fraction），and the reaction temperature and the reaction time were 75 ℃ and 15 min，respectively.