Molecular modeling of binary liquid‐phase adsorption of aromatics in silicalite

Chempath, Shaji; Snurr, Randall Q.; Low, John J.

doi:10.1002/aic.10040

Cited by 59 publications

(70 citation statements)

References 26 publications

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“…Physisorption from a dense phase, e.g., a liquid, can be related to gas phase physisorption through a Born-Haber cycle; see Figure 3a. 15 The four corners in this Born-Haber cycle correspond to ideal vapor phase, dense bulk or liquid bulk phase,…”

Section: Physisorption Of Hydrocarbons In Zeolites From a Dense Bulkmentioning

confidence: 99%

A Unified Single-Event Microkinetic Model for Alkane Hydroconversion in Different Aggregation States on Pt/H−USY-Zeolites

et al. 2006

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A single-event microkinetic model for the catalytic hydroconversion of hydrocarbons on Pt/H-US-Y bifunctional zeolite catalysts developed for low-pressure vapor phase conditions was extended to cover high-pressure vapor phase and liquid phase conditions. The effect of the density of the bulk hydrocarbon phase on the physisorption as well as on the protonation steps of the reaction network was accounted for explicitly and can be interpreted in terms of "compression" of the hydrocarbon sorbate inside the zeolite pores and "solvation" of the catalyst framework by the dense bulk hydrocarbon phase. The bulk phase density effect on the physisorbed state is described via a single excess free enthalpy of physisorption. A dense bulk hydrocarbon phase destabilizes the sorbate molecules inside the catalyst pores. An expression of the excess free enthalpy of physisorption involving the fugacity coefficient and a zeolite dependent factor allows description of physisorption data. Typical excess free enthalpy values are in the range 1.5-5.1 kJ mol(-1) increasing with carbon number in the series of C5-C16 alkanes. At high-pressure vapor phase and liquid phase conditions, the excess standard protonation enthalpy is estimated at -7.8 kJ mol(-1) leading to relatively more stable carbenium ions at dense bulk phase conditions. As a result of the excess physisorption and protonation properties, the lightest hydrocarbons in mixtures are more competitive at dense phase conditions and their conversion is enhanced compared to low-density conditions.

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Section: Physisorption Of Hydrocarbons In Zeolites From a Dense Bulkmentioning

confidence: 99%

A Unified Single-Event Microkinetic Model for Alkane Hydroconversion in Different Aggregation States on Pt/H−USY-Zeolites

et al. 2006

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“…The decrease of the PX/OX separation factor with increasing PX vapor pressure can be attributed to the enhanced OX sorption rate by the increased PX loading level [10]. However, the increase of xylene loading level in MFI zeolite is limited to a maximum of about eight PX molecules per unit cell above a certain vapor pressure depending on temperature [15,23].…”

Section: Effect Of Feed Partial Pressurementioning

confidence: 99%

“…It is known that for zeolite membranes, high permselectivities between individual components often cannot be translated into separation factors for mixtures of these components, especially for systems containing adsorbing molecules. The xylene isomers are strongly adsorbing to MFI zeolites with comparable heats of adsorption and large loading numbers at high vapor pressures because of the flexibility of the MFI framework when in contact with aromatic molecules [10,15,16]. The diffusion behaviors of xylenes in zeolitic pores are strongly affected by the presence of other isomers due to strong sorbate-framework and sorbate-sorbate interactions.…”

Section: Introductionmentioning

confidence: 99%

Separation of p-xylene from multicomponent vapor mixtures using tubular MFI zeolite mmbranes

Dong

Nenoff

et al. 2006

Journal of Membrane Science

109

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“…In contrast to the p-xylene/toluene mixture on PARA silicalite, IAS works very well due to the similar adsorption capacities of components. 30 On the subject of selectivity predicted by the IAS model a very interesting paper has been published recently by de Oliviera et al 31 The authors pointed out the importance of the fact that the pore size distribution (PSD) of components in a mixture can be different from the PSD of individual components, and they proposed a simple mixing rule, assuming that the ''contribution'' of individual PSD curves to the global adsorption is proportional to the molar fraction of components in the gas phase. The calculated, taking this into account, selectivity can be remarkably different from that obtained from the IAS concept.…”

Section: Introductionmentioning

confidence: 99%

New insights into the ideal adsorbed solution theory

Furmaniak

Koter

Terzyk

et al. 2015

Phys. Chem. Chem. Phys.

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The GCMC technique is used for simulation of adsorption of CO2-CH4, CO2-N2 and CH4-N2 mixtures (at 298 K) on six porous carbon models. Next we formulate a new condition of the IAS concept application, showing that our simulated data obey this condition. Calculated deviations between IAS predictions and simulation results increase with the rise in pressure as in the real experiment. For the weakly adsorbed mixture component the deviation from IAS predictions is higher, especially when its content in the gas mixture is low, and this is in agreement with the experimental data. Calculated activity coefficients have similar plots to deviations between IAS and simulations, moreover obtained from simulated data activity coefficients are similar qualitatively as well as quantitatively to experimental data. Since the physical interpretation of activity coefficients is completely lacking we show for the first time that they can be described by the formulas derived from the expression for G(ex) for the ternary mixture. Finally we also for the first time show the linear relationship between the chemical potentials of nonideal and ideal solutions and the reduced temperature of interacting mixture components, and it is proved that the deviation from ideality is larger if adsorption occurs in a more microporous system.

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Molecular modeling of binary liquid‐phase adsorption of aromatics in silicalite

Cited by 59 publications

References 26 publications

A Unified Single-Event Microkinetic Model for Alkane Hydroconversion in Different Aggregation States on Pt/H−USY-Zeolites

A Unified Single-Event Microkinetic Model for Alkane Hydroconversion in Different Aggregation States on Pt/H−USY-Zeolites

Separation of p-xylene from multicomponent vapor mixtures using tubular MFI zeolite mmbranes

New insights into the ideal adsorbed solution theory

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