Improved performance of hierarchical Fe-ZSM-5 in the direct oxidation of benzene to phenol by N2O

• Hierarchical Fe-ZSM-5 zeolites were hydrothermally synthesized.
• A silane coupling agent of 3-glycidoxypropyltrimethoxysilane was used.
• Direct oxidation of benzene to phenol was conducted on the hierarchical Fe-ZSM-5.
• The hierarchical Fe-ZSM-5 showed better activity and stability.
• n-Butane uptake experiments indicated the improvement of internal mass-transfer.

Hierarchical Fe-ZSM-5 zeolites were directly synthesized from a zeolitic synthesis system in the presence of a silane coupling agent 3-glycidoxypropyltrimethoxysilane (GPTMS). The structure and morphology of the hierarchical Fe-ZSM-5 synthesized with different amount of GPTMS were characterized by XRD, SEM, TEM, and N2 adsorption-desorption techniques. UV–vis and NH3-TPD were used to investigate the state of iron species and acidity, respectively. The steaming activated hierarchical Fe-ZSM-5 were used as catalysts in the direct oxidation of benzene to phenol (BTOP) with N2O as oxidant, showing an improved performance in terms of both activity and stability compared to Fe-ZSM-5 synthesized in the absence of GPTMS. A comparison study on the n-butane uptakes in Fe-ZSM-5 zeolites indicated the internal mass-transfer limitations of the hierarchical Fe-ZSM-5 zeolites were significantly improved.

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