Activation energy of hydride transfer between isobutane molecules on USY zeolite. First direct experimental measurement by in situ MAS NMR using mixtures of isotopomers

被引：15

作者：

Borghese, Sophie ^{[1
]}

Haouas, Mohamed ^{[2
]}

Sommer, Jean ^{[1
]}

Taulelle, Francis ^{[2
]}

机构：

[1] Univ Strasbourg, Inst Chim, LASYRO, Strasbourg, France

[2] Univ Versailles St Quentin, ILV, Tectospin, Versailles, France

来源：

JOURNAL OF CATALYSIS | 2013年 / 305卷

关键词：

Nuclear magnetic resonance spectroscopy; Isotopic labeling; Branched alkanes; Acid catalysis; Regioselectivity; Carbenium ions; In situ NMR; H/D exchange; H BOND ACTIVATION; ACID-CATALYZED REACTIONS; TERT-BUTYL CATION; SOLID-STATE NMR; H/D EXCHANGE; SMALL ALKANES; HYDROCARBONS; TEMPERATURE; CARBENIUM; H-ZSM-5;

D O I：

10.1016/j.jcat.2013.05.004

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

In situ C-13 and H-1 MAS NMR study of hydride transfer between C-13 and H-2 isotopically labeled isobutanes on acidic zeolites enabled to estimate the activation energy of this process for the first time and allow full re-evaluation of C-H bond activation mechanism at moderate temperatures. The hydride transfer was shown to occur on the methine position of the molecule. The rates of the intermolecular H/D exchange were measured at different temperatures, and the activation energy was determined to be ca. 55 kJ/mol. These new results definitively support the carbenium mechanism for alkane activation over zeolites through a bimolecular process. (C) 2013 Elsevier Inc. All rights reserved.

引用

页码：130 / 134

页数：5

共 30 条

[1] Kinetics of H/D exchange for n-butane on zeolite H-ZSM-5 studied with 1H MAS NMR in situ [J].

Arzumanov, Sergei S. ;

Stepanov, Alexander C. ;

Freude, Dieter .

JOURNAL OF PHYSICAL CHEMISTRY C, 2008, 112 (31) :11869-11874

[2] HYDROGEN EXCHANGE REACTIONS OF THE BUTANES IN SULFURIC ACID [J].

BEECK, O ;

OTVOS, JW ;

STEVENSON, DP ;

WAGNER, CD .

JOURNAL OF CHEMICAL PHYSICS, 1949, 17 (04) :418-419

[3] Insights into reaction mechanisms in heterogeneous catalysis revealed by in situ NMR spectroscopy [J].

Blasco, Teresa .

CHEMICAL SOCIETY REVIEWS, 2010, 39 (12) :4685-4702

[4] Are carbenium and carbonium ions reaction intermediates in zeolite-catalyzed reactions? [J].

Boronat, M. ;

Corma, A. .

APPLIED CATALYSIS A-GENERAL, 2008, 336 (1-2) :2-10

[5] Theoretical study on the mechanism of the hydride transfer reaction between alkanes and alkylcarbenium ions [J].

Boronat, M ;

Viruela, P ;

Corma, A .

JOURNAL OF PHYSICAL CHEMISTRY B, 1997, 101 (48) :10069-10074

[6] Proton exchange of small hydrocarbons over acidic chabazite:: Ab initio study of entropic effects [J].

Bucko, Tomas ;

Benco, Lubomir ;

Hafner, Juergen ;

Angyan, Janos G. .

JOURNAL OF CATALYSIS, 2007, 250 (01) :171-183

[7] Mechanism of alkane dehydrogenation catalyzed by acidic zeolites: Ab initio transition path sampling [J].

Bucko, Tomas ;

Benco, Lubomir ;

Dubay, Orest ;

Dellago, Christoph ;

Hafner, Juergen .

JOURNAL OF CHEMICAL PHYSICS, 2009, 131 (21)

[8] Liquid-phase alkylation of benzene with octenes over Y zeolites: Kinetic modeling including acidity descriptors [J].

Craciun, Ionel ;

Reyniers, Marie-Francoise ;

Marin, Guy B. .

JOURNAL OF CATALYSIS, 2012, 294 :136-150

[9] Bronsted acid site and pore controlled siting of alkane sorption in acidic molecular sieves [J].

Eder, F ;

Stockenhuber, M ;

Lercher, JA .

JOURNAL OF PHYSICAL CHEMISTRY B, 1997, 101 (27) :5414-5419

[10] The initial stages of solid acid-catalyzed reactions of adsorbed propane. A mechanistic study by in situ MAS NMR [J].

Haouas, M ;

Walspurger, S ;

Taulelle, F ;

Sommer, J .

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2004, 126 (02) :599-606

← 1 2 3 →