Preferential dealumination of Zn/H-ZSM-5 and its high and stable activity for ethane dehydroaromatization

Hikaru Saito, Satoshi Inagaki, Kiria Kojima, Qiao Han, Tomohiro Yabe, Shuhei Ogo, Yoshihiro Kubota, Yasushi Sekine

Research output: Contribution to journalArticle

25 Citations (Scopus)

Abstract

The effect of steam treatment on Zn/H-ZSM-5 catalysts prepared by an ion-exchange method for non-oxidative ethane dehydroaromatization was investigated. Steam treatment of Zn/H-ZSM-5 after Zn loading improved its catalytic stability on aromatic hydrocarbon formation including benzene, toluene and xylene. Temperature programmed oxidation measurements demonstrated that the steam treatment brought suppression of coke formation and it contributed to the improvement in the catalytic stability. Characterization of the local structure of the zeolites by 27Al and 29Si magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy revealed that dealumination of the framework Al in the MFI structure proceeded by steam treatment. Results of temperature programmed desorption of ammonia indicate the decrease in the amount of acid sites by the steam treatment. The slight changes in Zn content and its electronic state indicated that bared Al related with H+, not with Zn2+, in the MFI structure was preferentially dealuminated by steam treatment. The preferential dealumination led to suppression of coke formation by the selective removal of undesirable Brønsted acid sites.

Original languageEnglish
Pages (from-to)76-81
Number of pages6
JournalApplied Catalysis A: General
Volume549
DOIs
Publication statusPublished - 2018

Keywords

  • Coke deposition
  • Ethane dehydroaromatization
  • Preferential dealumination
  • Zeolite catalyst

ASJC Scopus subject areas

  • Catalysis
  • Process Chemistry and Technology

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