Mechanism Studies of the Conversion of 13C-Labeled n-Butane on Zeolite H-ZSM-5 by Using 13C Magic Angle Spinning NMR Spectroscopy and GC–MS Analysis
Научная публикация
| Общее |
Язык:
Английский,
Жанр:
Статья (Full article),
Статус опубликования:
Опубликована,
Оригинальность:
Оригинальная
|
| Журнал |
Chemistry - A European Journal
ISSN: 0947-6539
, E-ISSN: 1521-3765
|
| Вых. Данные |
Год: 2006,
Том: 12,
Номер: 2,
Страницы: 457-465
Страниц
: 9
DOI:
10.1002/chem.200500382
|
| Ключевые слова |
Butane, GC-MS analysis, NMR spectroscopy, Reaction mechanisms, Zeolites |
| Авторы |
Luzgin Mikhail V.
1
,
Stepanov Alexander G.
1
,
Arzumanov Sergei S.
1
,
Rogov Vladimir A.
1
,
Parmon Valentin N.
1
,
Wang Wei
2
,
Hunger Michael
2
,
Freude Dieter
3
|
| Организации |
| 1 |
Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Prosp. Akademika Lavrentieva 5, Novosibirsk 630090 (Russia)
|
| 2 |
Institute of Chemical Technology, University of Stuttgart, 70550 Stuttgart (Germany)
|
| 3 |
Abteilung Grenzflachenphysik, Universitat Leipzig, Linnestrasse 5, 04103 Leipzig (Germany)
|
|
Информация о финансировании (6)
|
1
|
Deutsche Forschungsgemeinschaft
|
FR 902/15
|
|
2
|
Российский фонд фундаментальных исследований
|
04-03-32372
|
|
3
|
North Atlantic Treaty Organization
|
PST.CLG.979335
|
|
4
|
International Association for the Promotion of Co-operation with Scientists from the New Independent States of the Former Soviet Union
|
03-51-5286
|
|
5
|
Президиум СО РАН
|
|
|
6
|
Региональный общественный Фонд содействия отечественной науке
|
|
By using 13C MAS NMR spectroscopy (MAS=magic angle spinning), the conversion of selectively 13C-labeled n-butane on zeolite H-ZSM-5 at 430–470 K has been demonstrated to proceed through two pathways: 1) scrambling of the selective 13C-label in the n-butane molecule, and 2) oligomerization–cracking and conjunct polymerization. The latter processes (2) produce isobutane and propane simultaneously with alkyl-substituted cyclopentenyl cations and condensed aromatic compounds. In situ 13C MAS NMR and complementary ex situ GC–MS data provided evidence for a monomolecular mechanism of the 13C-label scrambling, whereas both isobutane and propane are formed through intermolecular pathways. According to 13C MAS NMR kinetic measurements, both pathways proceed with nearly the same activation energies (Ea=75 kJ mol−1 for the scrambling and 71 kJ mol−1 for isobutane and propane formation). This can be rationalized by considering the intermolecular hydride transfer between a primarily initiated carbenium ion and n-butane as being the rate-determining stage of the n-butane conversion on zeolite H-ZSM-5.