On the relationship between coke formation chemistry and catalyst deactivation

Journal Article · Sun Nov 01 04:00:00 EST 1992 · Journal of Catalysis; (United States)

DOI:https://doi.org/10.1016/0021-9517(92)90027-F· OSTI ID:5602081

Groten, W A; Wojciechowski, B W; Hunter, B K ^[1]

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1. Queen's Univ., Kingston (Canada)

A link has been observed between the decline in catalyst activity and coke formation in the cracking of n-nonane. The link involves the chemistry and kinetics of the reaction, as well as the chemical structure of coke as observed by [sup 13]C CP/MAS-NMR. The authors find that the chemical structure of the surface species normally analyzed as coke plays an important role in the activity of the catalyst. This reflects the influence of the structure of surface carbenium ions on their reactivity in chain propagation and in olefin-forming, site-releasing desorption reactions. Both these processes are vital to the maintenance of catalyst activity. As the average surface species becomes more dehydrogenated, it also becomes less reactive both in bimolecular chain propagation with gas phase reactant molecules and in olefin formation by desorption. This time-dependent loss of reactivity of the average carbenium ion manifests itself in a decline in total catalyst activity with time on stream. 21 refs., 4 figs., 1 tab.

• OSTI ID: 5602081
• Journal Information: Journal of Catalysis; (United States), Journal Name: Journal of Catalysis; (United States) Vol. 138:1; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

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CATALYSIS
CATALYSTS
CATALYTIC EFFECTS
CATIONS
CHARGED PARTICLES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
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INORGANIC ION EXCHANGERS
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MOLECULAR STRUCTURE
ORGANIC COMPOUNDS
PYROLYSIS
REACTION KINETICS
SILICATE MINERALS
SORPTION
THERMOCHEMICAL PROCESSES
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