Proton exchange of small hydrocarbons over acidic chabazite: Ab initio study of entropic effects

Autor(en)

Tomas Bucko, Lubomir Benco, Juergen Hafner, János G. Angyan

Abstrakt

The proton-exchange reaction of a series of short hydrocarbons over an acidic zeolite (chabazite) was studied using periodic density functional theory (DFT) calculations. It was found that the chain length of hydrocarbons does not have a significant effect on the height of the potential-energy barrier. The experimentally observed regioselectivity between methyl and methylene groups in propane and between methyl and methine groups in isobutane was shown to be an entropic effect. In addition to the direct H-exchange, a mechanism mediated by a methylpropene molecule recently suggested by experimentalists was explored. It was found that entropy plays a very important role in driving the reaction. (c) 2007 Elsevier Inc. All rights reserved.

Organisation(en)

Computergestützte Materialphysik

Externe Organisation(en)

Université Henri-Poincaré (Nancy I)

Journal

Journal of Catalysis

Band

250

Seiten

171-183

Anzahl der Seiten

13

ISSN

0021-9517

DOI

https://doi.org/10.1016/j.jcat.2007.05.025

Publikationsdatum

2007

Peer-reviewed

Ja

ÖFOS 2012

1030 Physik, Astronomie

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/b5c0b8fb-c9cb-4e5c-a32b-fa000600e6f3