Peculiarities observed in H-D exchange between perdeuterioisobutane and H-zeolites

Journal Article · Sun Jan 01 04:00:00 EST 1995 · Journal of Catalysis

DOI:https://doi.org/10.1006/jcat.1995.1001· OSTI ID:75788

Engelhardt, J; Hall, W K ^[1]

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1. Univ. of Pittsburgh, PA (United States)

H-D exchange between perdeuterioisobutane and NaH-Y-zeolites and H-mordenite (H-M) was studied using the pulse technique. Nine of the ten D atoms in the isobutane molecule were exchanged for H on the most acidic Y-zeolites at the lowest temperature (200{degrees}C) where H-D exchange was observed, while other transformations of isobutane were not. The reaction is thought to be initiated by protonation of the tertiary C-D bond on the Bronsted acid sites of the catalyst and the exchange to proceed via the t-butyl carbenium ion intermediate. Release of the ion from the surface occurs via hydride transfer conserving the identity of the tertary position. At higher temperatures and over the more acidic H-mordenite at even lower temperature (125{degrees}C) an extensive intermolecular H-D exchange occurs between perdeuterioisobutane and its exchanged products. A more detailed understanding of this reaction chemistry is developed herein. 16 refs., 9 figs., 4 tabs.

• DOE Contract Number: FG02-87ER13774
• OSTI ID: 75788
• Journal Information: Journal of Catalysis, Journal Name: Journal of Catalysis Journal Issue: 1 Vol. 151; ISSN 0021-9517; ISSN JCTLA5
• Country of Publication: United States
• Language: English

Related Subjects

2-METHYLPROPANE
40 CHEMISTRY
CATALYSTS
DEUTERIUM COMPOUNDS
INORGANIC ACIDS
ISOTOPIC EXCHANGE
ZEOLITES