Sulfur-tolerant Pt-supported catalysts for benzene hydrogenation. II. Influence of cation exchange level for Pt/MOR-based catalysts

L. Simon, J.G. van Ommen, A. Jentys, J.A. Lercher

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

Two reaction pathways are described for the hydrogenation of benzene over Pt/MOR, i.e., (i) on the metal particles and (ii) on Brønsted acid sites of MOR at the boundary to the metal, with atomic hydrogen being dissociated on the metal. The ratio between the two pathways depends on the zeolite acid site concentration and on the available metal surface sites. The deactivation of fully H+ ion exchanged zeolites and the markedly slower intrinsic rate on Na+ ion exchanged samples led to a pronounced maximum in the steady-state activity for benzene hydrogenation with partly H+ exchanged samples. At high pressure and in the presence of thiophene, the benzene hydrogenation activity of Pt/MOR was higher via the pathway involving Brønsted acid sites than via the pathway involving only Pt. Therefore, in the presence of thiophene the type of alkali cation exchanged did not significantly influence activity, whereas Brønsted acid site concentration did. The relative sulfur tolerance of Pt/MOR during benzene hydrogenation was shown to depend on (i) the acid site concentration, which increases both the benzene conversion and the rate of C–C bond breaking leading to coke formation, and (ii) the partial pressure of hydrogen, which increases the concentration of hydrogen atoms available for hydrogenating benzene molecules activated via both pathways.
Original languageUndefined
Pages (from-to)434-442
Number of pages9
JournalJournal of catalysis
Volume203
Issue number2
DOIs
Publication statusPublished - 2001

Keywords

  • Sulfur tolerance
  • IR-74567
  • Benzene hydrogenation
  • METIS-204815

Cite this

Simon, L. ; van Ommen, J.G. ; Jentys, A. ; Lercher, J.A. / Sulfur-tolerant Pt-supported catalysts for benzene hydrogenation. II. Influence of cation exchange level for Pt/MOR-based catalysts. In: Journal of catalysis. 2001 ; Vol. 203, No. 2. pp. 434-442.
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abstract = "Two reaction pathways are described for the hydrogenation of benzene over Pt/MOR, i.e., (i) on the metal particles and (ii) on Br{\o}nsted acid sites of MOR at the boundary to the metal, with atomic hydrogen being dissociated on the metal. The ratio between the two pathways depends on the zeolite acid site concentration and on the available metal surface sites. The deactivation of fully H+ ion exchanged zeolites and the markedly slower intrinsic rate on Na+ ion exchanged samples led to a pronounced maximum in the steady-state activity for benzene hydrogenation with partly H+ exchanged samples. At high pressure and in the presence of thiophene, the benzene hydrogenation activity of Pt/MOR was higher via the pathway involving Br{\o}nsted acid sites than via the pathway involving only Pt. Therefore, in the presence of thiophene the type of alkali cation exchanged did not significantly influence activity, whereas Br{\o}nsted acid site concentration did. The relative sulfur tolerance of Pt/MOR during benzene hydrogenation was shown to depend on (i) the acid site concentration, which increases both the benzene conversion and the rate of C–C bond breaking leading to coke formation, and (ii) the partial pressure of hydrogen, which increases the concentration of hydrogen atoms available for hydrogenating benzene molecules activated via both pathways.",
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Sulfur-tolerant Pt-supported catalysts for benzene hydrogenation. II. Influence of cation exchange level for Pt/MOR-based catalysts. / Simon, L.; van Ommen, J.G.; Jentys, A.; Lercher, J.A.

In: Journal of catalysis, Vol. 203, No. 2, 2001, p. 434-442.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Sulfur-tolerant Pt-supported catalysts for benzene hydrogenation. II. Influence of cation exchange level for Pt/MOR-based catalysts

AU - Simon, L.

AU - van Ommen, J.G.

AU - Jentys, A.

AU - Lercher, J.A.

PY - 2001

Y1 - 2001

N2 - Two reaction pathways are described for the hydrogenation of benzene over Pt/MOR, i.e., (i) on the metal particles and (ii) on Brønsted acid sites of MOR at the boundary to the metal, with atomic hydrogen being dissociated on the metal. The ratio between the two pathways depends on the zeolite acid site concentration and on the available metal surface sites. The deactivation of fully H+ ion exchanged zeolites and the markedly slower intrinsic rate on Na+ ion exchanged samples led to a pronounced maximum in the steady-state activity for benzene hydrogenation with partly H+ exchanged samples. At high pressure and in the presence of thiophene, the benzene hydrogenation activity of Pt/MOR was higher via the pathway involving Brønsted acid sites than via the pathway involving only Pt. Therefore, in the presence of thiophene the type of alkali cation exchanged did not significantly influence activity, whereas Brønsted acid site concentration did. The relative sulfur tolerance of Pt/MOR during benzene hydrogenation was shown to depend on (i) the acid site concentration, which increases both the benzene conversion and the rate of C–C bond breaking leading to coke formation, and (ii) the partial pressure of hydrogen, which increases the concentration of hydrogen atoms available for hydrogenating benzene molecules activated via both pathways.

AB - Two reaction pathways are described for the hydrogenation of benzene over Pt/MOR, i.e., (i) on the metal particles and (ii) on Brønsted acid sites of MOR at the boundary to the metal, with atomic hydrogen being dissociated on the metal. The ratio between the two pathways depends on the zeolite acid site concentration and on the available metal surface sites. The deactivation of fully H+ ion exchanged zeolites and the markedly slower intrinsic rate on Na+ ion exchanged samples led to a pronounced maximum in the steady-state activity for benzene hydrogenation with partly H+ exchanged samples. At high pressure and in the presence of thiophene, the benzene hydrogenation activity of Pt/MOR was higher via the pathway involving Brønsted acid sites than via the pathway involving only Pt. Therefore, in the presence of thiophene the type of alkali cation exchanged did not significantly influence activity, whereas Brønsted acid site concentration did. The relative sulfur tolerance of Pt/MOR during benzene hydrogenation was shown to depend on (i) the acid site concentration, which increases both the benzene conversion and the rate of C–C bond breaking leading to coke formation, and (ii) the partial pressure of hydrogen, which increases the concentration of hydrogen atoms available for hydrogenating benzene molecules activated via both pathways.

KW - Sulfur tolerance

KW - IR-74567

KW - Benzene hydrogenation

KW - METIS-204815

U2 - 10.1006/jcat.2001.3339

DO - 10.1006/jcat.2001.3339

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