Direct Methane-Methanol and Benzene-Phenol Conversions on Fe-ZSM-5 Zeolite: Theoretical Predictions on the Reaction Pathways and Energetics

Kazunari Yoshizawa, Yoshihito Shiota, Takashi Yumura, Tokio Yamabe

Research output: Contribution to journalArticlepeer-review

129 Citations (Scopus)

Abstract

The reaction pathways and the energetics for the direct methane-methanol and benzene-phenol conversions that occur on the surface of Fe-ZSM-5 zeolite are analyzed from B3LYP DFT computations. We propose a reasonable model for "α-oxygen", a surface oxygen species responsible for the catalytic reactivities of Fe-ZSM-5 zeolite. Our model involves an iron-oxo species on the AlO4 surface site of the zeolite as a catalytic active center and as a source of oxygen. The essential features of the reaction pathways for the methane-methanol and benzene-phenol conversions are identical, especially in bonding characters. In the initial stages of each reaction, methane or benzene comes into contact with the active iron site of the "α-oxygen" model, leading to the reactant (methane or benzene) complex. After the initial complex is formed, each reaction takes place in a two-step concerted manner, via neither radical species nor ionic intermediates. The concerted reaction pathway for the methane (benzene) hydroxylation involves an H atom abstraction and a methyl (phenyl) migration at the iron active center. From computed energetics for the reaction pathways, we predict that the benzene hydroxylation should be energetically more favorable than the methane hydroxylation.

Original languageEnglish
Pages (from-to)734-740
Number of pages7
JournalJournal of Physical Chemistry B
Volume104
Issue number4
DOIs
Publication statusPublished - Feb 3 2000
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

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