Catalytic activity of modified ZSM-5 zeolites in the dehydrogenation and aromatization reactions of propane and n-butane

P. Fejes, J. Halász, I. Kiricsi, Z. Kele, Gy Tasi, I. Hannus, C. Fernandez, J. B. Nagy, A. Rockenbauer, Gy Schöbel

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

In order to enhance catalytic activity in the dehydrogenation and aromatization of light paraffins, a set of potential catalysts: (i) V(f)-ZSM-5 (originating from direct synthesis), (ii) V(ex)-ZSM-5 (“ex””: partial exchange of H+in H-ZSM-5 by VO2+ions), and (iii) solid exchange of H in H-ZSM-5 for Ga, In, and V by baking the mixtures of ZSM-5 with the respective oxides were investigated by physical (XRD, IR, ESR, MAS-NMR spectroscopy, and adsorption) and chemical methods. In the “as synthesized””V(f)-ZSM-5 sample V4+ions reside in framework positions according ESR and 51V-MAS-NMR spectra. Coincidence between experimental and theoretical spectra could be attained only by supposing the existence of two different framework surroundings. The structure of V(f)-ZSM-5 is strained: heating (especially in the presence of water vapour) causes release of V from the framework. Severe conditions cause clustering of V4+in the voids with the annihilation of hyperfine splitting in the ESR spectra. Catalytic results demonstrate that in the presence of modifyers propane and n-butane conversion turns from cracking to dehydrogenation and aromatization pathways.

Original languageEnglish
Pages (from-to)421-433
Number of pages13
JournalStudies in Surface Science and Catalysis
Volume75
Issue numberC
DOIs
Publication statusPublished - Jan 1 1993

ASJC Scopus subject areas

  • Catalysis
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

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