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Title: In situ {sup 13}C MAS NMR study of n-hexane conversion on Pt and Pd supported on basic materials

Abstract

n-Hexane conversion was studied in situ on Pt and Pd supported on aluminum-stabilized magnesium oxide and Pt on Zeolite KL catalysts (Pt/Mg(Al)O, Pd/Mg(Al)O and Pt/KL) by means of {sup 13}C MAS NMR spectroscopy. n-Hexane 1-{sup 13}C was used as a labelled reactant. Forty NMR lines corresponding to 14 different products were resolved and identified. The NMR line assignments were confirmed by adsorption of model compounds. The NMR results were further quantified and compared with continuous flow microreactor tests. Four parallel reaction pathways were identified under flow conditions: isomerization, cracking, dehydrocyclization, and dehydrogenation. Aromatization occurs via two reaction routes: (1) n-hexane dehydrogenation towards hexadienes and hexatrienes, followed by dehydrogenation of a cyclic intermediate. The former reaction pathway is prevented under NMR batch conditions. High pressures induced in the NMR cells at high reaction temperatures (573, 653 K) shift the reaction equilibrium towards hydrogenation. NMR experiments showed that on Pt catalysts aromatization occurs via a cyclohexane intermediate, whereas on Pd it takes place via methylcyclopentane ring enlargement. 54 refs., 15 figs., 3 tabs.

Authors:
; ; ;  [1]
  1. Facultes Universitaires N.D. de la Paix, Namur (Belgium); and others
Publication Date:
OSTI Identifier:
263705
Resource Type:
Journal Article
Journal Name:
Journal of Catalysis
Additional Journal Information:
Journal Volume: 158; Journal Issue: 2; Other Information: PBD: Feb 1996
Country of Publication:
United States
Language:
English
Subject:
02 PETROLEUM; 40 CHEMISTRY; ZEOLITES; CATALYTIC EFFECTS; HEXANE; CHEMICAL REACTIONS; PLATINUM; PALLADIUM; MAGNESIUM OXIDES; NUCLEAR MAGNETIC RESONANCE; CATALYST SUPPORTS; DEHYDROGENATION; ELECTROLYTIC CELLS; ISOMERIZATION; CATALYTIC CRACKING; CYCLIZATION; AROMATIZATION; REACTION INTERMEDIATES; HETEROGENEOUS CATALYSIS

Citation Formats

Ivanova, I I, Pasau-Claerbout, A, Seivert, M, and Derouane, E G. In situ {sup 13}C MAS NMR study of n-hexane conversion on Pt and Pd supported on basic materials. United States: N. p., 1996. Web. doi:10.1006/jcat.1996.0051.
Ivanova, I I, Pasau-Claerbout, A, Seivert, M, & Derouane, E G. In situ {sup 13}C MAS NMR study of n-hexane conversion on Pt and Pd supported on basic materials. United States. https://doi.org/10.1006/jcat.1996.0051
Ivanova, I I, Pasau-Claerbout, A, Seivert, M, and Derouane, E G. 1996. "In situ {sup 13}C MAS NMR study of n-hexane conversion on Pt and Pd supported on basic materials". United States. https://doi.org/10.1006/jcat.1996.0051.
@article{osti_263705,
title = {In situ {sup 13}C MAS NMR study of n-hexane conversion on Pt and Pd supported on basic materials},
author = {Ivanova, I I and Pasau-Claerbout, A and Seivert, M and Derouane, E G},
abstractNote = {n-Hexane conversion was studied in situ on Pt and Pd supported on aluminum-stabilized magnesium oxide and Pt on Zeolite KL catalysts (Pt/Mg(Al)O, Pd/Mg(Al)O and Pt/KL) by means of {sup 13}C MAS NMR spectroscopy. n-Hexane 1-{sup 13}C was used as a labelled reactant. Forty NMR lines corresponding to 14 different products were resolved and identified. The NMR line assignments were confirmed by adsorption of model compounds. The NMR results were further quantified and compared with continuous flow microreactor tests. Four parallel reaction pathways were identified under flow conditions: isomerization, cracking, dehydrocyclization, and dehydrogenation. Aromatization occurs via two reaction routes: (1) n-hexane dehydrogenation towards hexadienes and hexatrienes, followed by dehydrogenation of a cyclic intermediate. The former reaction pathway is prevented under NMR batch conditions. High pressures induced in the NMR cells at high reaction temperatures (573, 653 K) shift the reaction equilibrium towards hydrogenation. NMR experiments showed that on Pt catalysts aromatization occurs via a cyclohexane intermediate, whereas on Pd it takes place via methylcyclopentane ring enlargement. 54 refs., 15 figs., 3 tabs.},
doi = {10.1006/jcat.1996.0051},
url = {https://www.osti.gov/biblio/263705}, journal = {Journal of Catalysis},
number = 2,
volume = 158,
place = {United States},
year = {Thu Feb 01 00:00:00 EST 1996},
month = {Thu Feb 01 00:00:00 EST 1996}
}