A molecular dynamics study of hydrocarbons adsorbed in silicalite

Dumont, Denis; Bougeard, D.

doi:10.1016/0144-2449(95)00032-2

Cited by 42 publications

(24 citation statements)

References 28 publications

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“…For the ethane molecule, the result of Dumont and Bougeard [11] differs from ours by a factor of 2.81. The two simulations differ in many respects.…”

Section: The Diffusion Stepcontrasting

confidence: 44%

The Dehydrogenation Reaction of Light Alkanes Catalyzed by Zeolites

Furtado¹,

Milas²,

LINS³

et al. 2001

phys. stat. sol. (a)

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The several steps of the dehydrogenation reactions of ethane, propane and isobutane were studied by theoretical methods. Molecular dynamics simulation techniques have been used to study diffusion of the alkanes through the zeolite HZMS-5 framework. Adsorption energies were computed by the methods of molecular mechanics, molecular dynamics and Monte-Carlo. Molecular dynamics was also used to determine the preferred adsorption sites of the alkanes in silicalite and HZMS-5. The mechanism of the chemical reactions at the zeolite's acid site was investigated at the DFT(B3LYP) level of calculation using 6-31G ** and 6-311G ** basis sets, and 3 and 5 T cluster models to represent the zeolite. GIAO/B3LYP calculations were performed on the 3 and 5 T alkyalkoxides and the results were compared with experimental 13 C NMR data.

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“…For the ethane molecule, the result of Dumont and Bougeard [11] differs from ours by a factor of 2.81. The two simulations differ in many respects.…”

Section: The Diffusion Stepcontrasting

confidence: 44%

The Dehydrogenation Reaction of Light Alkanes Catalyzed by Zeolites

Furtado¹,

Milas²,

LINS³

et al. 2001

phys. stat. sol. (a)

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“…In a recent paper, Dumont et al, 20 studied the same topic with a rigid framework model accounting for the full flexibility and geometry of ethane. They obtained a diffusion coefficient of 5.9ϫ10 Ϫ9 m 2 s Ϫ1 for the same conditions as ours; their larger difference from experimental value could be due to the short trajectory carried out ͑42 ps͒, which leads to worse statistics, but the effect of the vibrating framework on the diffusive motion of ethane could also be important.…”

Section: Dϭ Limmentioning

confidence: 99%

Diffusion and vibrational relaxation of a diatomic molecule in the pore network of a pure silica zeolite: A molecular dynamics study

Demontis

Suffritti

Tilocca

1996

The Journal of Chemical Physics

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The vibrational relaxation and the diffusion of diatomic molecules in the zeolite silicalite have been studied through molecular dynamics simulations in the microcanonical statistical ensemble. The adopted model accounts for the vibrations of the framework and sorbed atoms using a harmonic potential for the silicalite and a Morse potential for the diatomic molecule. The results show that the framework favors the relaxation of diatomics oscillating at frequencies near to its characteristic vibrational frequencies, leading in such cases to lower relaxation times and to an increasing in the energy exchanged per collision. The diffusion of a two-site oscillating molecule representing ethane has been also investigated; the diffusion coefficient and the heat of adsorption agree very well with the experimental data. Arrhenius parameters for the diffusion have been calculated, and some insights into the diffusion mechanism have been obtained from log-log plots and by inspection of the distribution of the ethane molecules in the silicalite channels. Therefore the simplified model adopted seems to adequately describe the diffusive motion and the guest-host energy exchanges, and it could be useful in order to study simple bimolecular reactions in zeolites.

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“…These coordinates and the force constants were transferred from our previous study on silicalite [3,4]. The values of all parameters remained constant when going from the free to the trapped molecules.…”

Section: Potentialmentioning

confidence: 99%

“…The ® rst term was represented by the (6-12) Lennard-Jones potential from [10] previously used in our study of alkanes in silicalite [3,4]. The Coulombic term representing the interaction of the partial charges on the framework and on the molecules was included, although for hydrocarbons trapped in a siliceous framework it is expected to be very small because of the absence of cations and the low polarity of the C± H bond.…”

Section: Potentialmentioning

confidence: 99%

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A molecular dynamics study of methane encapsulated in dodecasil 3C

DUMONT¹,

BOUGEARD²

1997

Mol. Phys.

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This paper summarizes the results of a molecular dynamics study of the clathrate silicate dodecasil 3C with di erent methane ® llings, which covered the in¯uence of cavities on the behaviour of entrapped molecules. The simulations treat all degrees of freedom of methane at room temperature. The dynamics of methane is in¯uenced very little by use of a¯exible silicate framework, as compared with use of a rigid one. The calculated infrared and Raman spectra show that two types of molecular environment can be clearly recognized from the vibrational behaviour of the molecules. Also, in the low-frequency region the rigid molecule motions are well di erentiated. In small cages the molecules are located near the centres of cages, whereas in large cages the molecules move along the walls of the cavities while their orientation is nearly free.

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A molecular dynamics study of hydrocarbons adsorbed in silicalite

Cited by 42 publications

References 28 publications

The Dehydrogenation Reaction of Light Alkanes Catalyzed by Zeolites

The Dehydrogenation Reaction of Light Alkanes Catalyzed by Zeolites

Diffusion and vibrational relaxation of a diatomic molecule in the pore network of a pure silica zeolite: A molecular dynamics study

A molecular dynamics study of methane encapsulated in dodecasil 3C

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