| Methane activation and oxidation in sulfuric acid. | |
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MedLine Citation:
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PMID: 12203359 Owner: NLM Status: PubMed-not-MEDLINE |
Abstract/OtherAbstract:
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The H/D exchange observed when methane is contacted with D(2)SO(4) at 270-330 degrees C shows that the alkane behaves as a sigma base and undergoes rapid and reversible protonation at this temperature. DFT studies of the hydrogen exchange between a monomer and a dimer of sulfuric acid and methane show that the transition states involved in the exchange are bifunctional, that is one hydrogen atom is transferred from a hydroxy group in sulfuric acid to methane, while one hydrogen atom is abstracted from methane by a non-hydroxy oxygen atom in sulfuric acid. All the transition states include a CH(5) moiety, which shows similarities to the methanium ion CH(5) (+). The calculated potential activation energy of the hydrogen exchange for the monomer is 174 kJ mol(-1), which is close to the experimental value (176 kJ mol(-1)). Solvation of the monomer and the transition state of the monomer with an extra sulfuric acid molecule, decrease the potential activation energy by 6 kJ mol(-1). The acid-base process is in competition, however, with an oxidative process involving methane and sulfuric acid which leads to CO(2), SO(2), and water, and thus to a decrease of acidity and loss of reactivity of the medium. |
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Authors:
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Alain Goeppert; Peter Dinér; Per Ahlberg; Jean Sommer |
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Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: Chemistry (Weinheim an der Bergstrasse, Germany) Volume: 8 ISSN: 0947-6539 ISO Abbreviation: Chemistry Publication Date: 2002 Jul |
Date Detail:
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Created Date: 2002-08-30 Completed Date: 2003-08-08 Revised Date: 2009-08-04 |
Medline Journal Info:
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Nlm Unique ID: 9513783 Medline TA: Chemistry Country: Germany |
Other Details:
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Languages: eng Pagination: 3277-83 Citation Subset: - |
Affiliation:
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Laboratoire de Physico-Chimie des Hydrocarbures, Institut de Chimie, UMR 7513, Université Louis Pasteur 4, rue Blaise Pascal, 67070 Strasbourg Cedex, France. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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