Catalysis Letters, Vol.141, No.10, 1498-1505, 2011
Effects of Zinc and Magnesium Addition to ZSM-5 on the Catalytic Performances in 1-hexene Aromatization Reaction
Effects of Zn and Mg addition on the catalytic performances of ZSM-5 in 1-hexene aromatization and isomerization were investigated. NH3-TPD and Pyridine-IR spectra revealed that the addition of Zn could increase the Lewis acidity amount of the support. And the catalytic aromatization activity was improved. Introduction of Mg resulted in a decrease of total acidity, especially for BrI center dot nsted acid sites which was beneficial for the high iso-paraffin and liquid product yield. The optimal modification way on ZSM-5 was obtained as addition of Mg with successive Zn introduction which may lead to the presence of Zn species inside of the zeolite channel evidenced by XPS results. The close proximity of Zn species to BrI center dot nsted acid sites may enhance the synergy effect between them in the aromatization reaction. The optimized Zn-Mg/HZSM-5 sample also exhibited good catalytic performance when using FCC gasoline as reactant.