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Titolo:
Influence of the cation composition on the dynamics of xylenes in X-type zeolites
Autore:
Jobic, H; Bee, M; Methivier, A; Combet, J;
Indirizzi:
Inst Rech Catalyse, CNRS, F-69626 Villeurbanne, France Inst Rech CatalyseVilleurbanne France F-69626 9626 Villeurbanne, France Univ Grenoble 1, Spectrometrie Phys Lab, F-38402 St Martin Dheres, France Univ Grenoble 1 St Martin Dheres France F-38402 St Martin Dheres, France Inst Francais Petr, F-92852 Rueil Malmaison, France Inst Francais Petr Rueil Malmaison France F-92852 ueil Malmaison, France Inst Max Von Laue Paul Langevin, F-38042 Grenoble, France Inst Max Von Laue Paul Langevin Grenoble France F-38042 Grenoble, France
Titolo Testata:
MICROPOROUS AND MESOPOROUS MATERIALS
fascicolo: 2-3, volume: 42, anno: 2001,
pagine: 135 - 155
SICI:
1387-1811(200102)42:2-3<135:IOTCCO>2.0.ZU;2-Q
Fonte:
ISI
Lingua:
ENG
Soggetto:
ELASTIC NEUTRON-SCATTERING; MONTE-CARLO SIMULATIONS; AROMATIC-HYDROCARBONS; MOLECULAR-DYNAMICS; NAY ZEOLITE; DIFFUSION; ADSORPTION; BENZENE; FAUJASITE;
Keywords:
xylenes; NaX; BaX; dynamics; quasi-elastic neutron scattering;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
29
Recensione:
Indirizzi per estratti:
Indirizzo: Jobic, H Inst Rech Catalyse, CNRS, 2 Ave Albert Einstein, F-69626 Villeurbanne, France Inst Rech Catalyse 2 Ave Albert Einstein Villeurbanne France F-69626
Citazione:
H. Jobic et al., "Influence of the cation composition on the dynamics of xylenes in X-type zeolites", MICROP M M, 42(2-3), 2001, pp. 135-155

Abstract

The rotational and translational dynamics of para- and meta-xylene in NaX and BaX zeolites have been measured by quasi-elastic neutron scattering. Two different neutron spectrometers were used to cover time scales ranging from a picosecond to a few nanoseconds. At short times, rotational motions ofthe methyl groups and oscillations of xylenes adsorbed ill front of cations in the supercages are observed. In NaX, larger amplitude motions are found compared with BaX. Even at 460 K, only the methyl groups of para-xylene are rotating in BaX, the aromatic ring is immobile on a time scale of 10 ps. At longer times, diffusion between cages can be measured in NaX, the diffusivity of the para-isomer being slightly larger than that of the meta-isomer. However, for both xylenes in BaX, only jumps between adsorption sites within a supercage are observed on the same time scale, indicating a much lower intercage migration in this zeolite. (C) 2001 Elsevier Science B.V. All rights reserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 01/06/20 alle ore 01:56:56