Surface species formed during propane aromatization over Zn/MFI catalyst as determined by in situ spectroscopic techniques

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• 作者：Irina I. Ivanova ; Yuriy G. Kolyagin ; Vitaly V. Ordomsky ; Ekaterina V. Asachenko ; Elena M. Pasynkova ; Yuri A. Pirogov
• 关键词：Zn/MFI zeolite ; Zincorganic surface species ; Propane aromatization mechanism ; ¹H ; ¹³C MAS NMR in situ ; IR spectroscopy in situ
• 刊名：Journal of Molecular Catalysis A: Chemical
• 出版年：2009
• 出版时间：15 June 2009
• 年：2009
• 卷：305
• 期：1-2
• 页码：47-53
• 全文大小：661 K

文摘

The propane conversion was studied by in situ ¹H, ¹³C MAS NMR and IR spectroscopic techniques over Zn/H-MFI catalyst. Propane 2-¹³C, propane 1-¹³C, propene 1-¹³C, propene 2-¹³C and benzene ¹³C were used as labelled reactants. The results pointed to the propane activation via dissociative adsorption over zinc oxide sites, as evidenced by zinc propyl surface species observation at the onset of propane conversion. Zinc propyl species convert further into propene, which forms asymmetric π-complex with zinc cations. At the later reaction steps, propene oligomerizes to give charge delocalized carbanionic species stabilized on zinc cations. The role of carbanionic species in consecutive reaction steps is discussed.