Sorption and diffusion of gaseous hydrocarbons in synthetic mordenite

Satterfield, Charles N.; Frabetti, Alton J.

doi:10.1002/aic.690130426

Cited by 56 publications

(37 citation statements)

References 15 publications

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“…1. The new force field shows improved results over previous simulations for ethane and the calculated results for C 5 -C 9 are also in good agreement with To test the applicability of the new force field further, the adsorption isotherms of ethane, propane, butane, and hexane were computed and compared with experimental data, [2][3][4]8 as shown in Fig. 2-5.…”

Section: Validation Of the New Force Field For Na-mor Zeolitesmentioning

confidence: 86%

“…Although many experimental investigations have been performed on the adsorption properties of Na-MOR zeolites, [2][3][4][5][6][7][8][9][10][11][12] our understanding of the effects of cations on the adsorption properties at the molecular level is as yet incomplete. Molecular simulations might be a suitable tool to complement experimental efforts.…”

Section: Introductionmentioning

confidence: 99%

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Molecular simulation of adsorption of alkanes in sodium MOR-type zeolites using a new force field

Liu

Smit

2006

Phys. Chem. Chem. Phys.

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Section: Validation Of the New Force Field For Na-mor Zeolitesmentioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Molecular simulation of adsorption of alkanes in sodium MOR-type zeolites using a new force field

Liu

Smit

2006

Phys. Chem. Chem. Phys.

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“…Further advantage is the availability of experimental and simulation data for comparison. [16][17][18][19]23,26,28 2.1. Zeolite Models.…”

Section: Methodsmentioning

confidence: 99%

The Influence of Non-framework Sodium Cations on the Adsorption of Alkanes in MFI- and MOR-Type Zeolites

2002

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Molecular simulations were performed for the adsorption of methane, ethane, and propane in MFI-and MORtype zeolites with various nonframework sodium and framework aluminum densities. The position of the nonframework sodium cations determined by Monte Carlo simulations is in agreement with positions determined by X-ray diffraction. The position and density of the sodium and aluminum atoms in the zeolite have a large influence on the adsorption of alkanes. The computed adsorption isotherms and Henry coefficients agree well with those obtained experimentally. Finally, we show that Configurational Bias Monte Carlo (CBMC) simulations are able to provide a better understanding of the effect of nonframework sodium on the selective adsorption of binary mixtures of isomers by these structures. Our results show that increasing the nonframework sodium density in MFI-type zeolites increasingly blocks the intersections and thereby increases the selectivity of MFI-type zeolites for adsorbing linear alkanes. By contrast, increasing the nonframework sodium density in MOR-type zeolites increases the number of sites favorable for adsorbing small linear alkanes.

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“…In an earlier study (11) the diffusion characteristics of the C1 to C4 paraffin hydrocarbon vapors into single crystals of sodium mordenite were investigated using a constant-pressure apparatus. The present study used a sample of the identical material previously used but in a different type of sorption apparatus that permitted accurate measurement of faster sorption processes.…”

mentioning

confidence: 99%

“…The present study used a sample of the identical material previously used but in a different type of sorption apparatus that permitted accurate measurement of faster sorption processes. The sodiummordenite comprised single crystals of average dimensions 21 x 21 x 33 p , described previously in detail (11 ) . Some additional information concerning the possible presence of extrazeolitic pores in the single crystals of this material was obtained by sorption of krypton at the temperature of liquid nitrogen, -196°C.…”

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confidence: 99%

Diffusion in sodium mordenite

Satterfield

Margetts

1971

AIChE Journal

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The rotes of diffusion of CH4, n-CaHlo, iso-GHIo, and GF1o into well-characterized single crystals of sodium mordenite were studied a t 25" to 100°C., using a rapidly responding constant-volume system. The diffusion coefficients are of the order of lo-* to sq. cm/ sec. and exhibit o maximum value with time, probably due to an initial temperature increase caused by the heat of sorption. The implications to catalysis of these and other studies of diffusion in zeolites ore discussed.The widespread recent application of zeolites (molecular sieves) in selective adsorption processes and in catalysis has focused attention on the diffusion characteristics of molecules inside the tiny pores of these materials, for this can have a profound effect on dispersion in adsorption Irocesses and on reaction activity and selectivity in catalyis. The molecular sieve crystals may be bonded together o form pellets or, as in cracking catalysts, they may be ncorporated into a gel matrix. However, diffusion studies eported on these forms of molecular sieves may be diffiult to interpret because of the complex pore structure )resent and uncertainties concerning the effect of the )elleting process, use of binders, etc., on the ease of access d diffusing molecules into the pores of the zeolite. By tudying single crystals of uniform size, the above diffibulties can be avoided but the experimental limitations set )y apparatus constraints and the heterogeneous nature of ven single crystals must be clearly recognized in interpreting results. The present study used a rapidly responding, constant-volume sorption system but the results emphasize that initial temperature transients that can occur in such an experimental apparatus may substantially affect the results reported. The zeolite was a well-characterized sample of sodium mordenite. The two-dimensional pore structure characteristic of mordenites enhances the effect of structural heterogeneities on diffusion. Markedly different sor tion and diffusion characteristics may be can greatly affect their behavior in adsorption and catalytic processes.In an earlier study (11) the diffusion characteristics of the C1 to C4 paraffin hydrocarbon vapors into single crystals of sodium mordenite were investigated using a constant-pressure apparatus. The present study used a sample of the identical material previously used but in a different type of sorption apparatus that permitted accurate measurement of faster sorption processes. The sodiummordenite comprised single crystals of average dimensions 21 x 21 x 33 p , described previously in detail (11 ) . Some Taking the surface tension as 15 dynes/cm. and the molar volume as 31 ml. (2) and neglecting the thickness of the found for di P erent samples of synthetic mordenite, which adsorbed layer on walls of the pores, adsorption of krypton at P/Po above 0.016 would represent sorption into pores above 7 A. diameter. By this procedure 17% of the pore volume would be in pores above 7 A. diameter and 11% in pores above 13A. diameter; 6% of the total represents pore...

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Sorption and diffusion of gaseous hydrocarbons in synthetic mordenite

Cited by 56 publications

References 15 publications

Molecular simulation of adsorption of alkanes in sodium MOR-type zeolites using a new force field

Molecular simulation of adsorption of alkanes in sodium MOR-type zeolites using a new force field

The Influence of Non-framework Sodium Cations on the Adsorption of Alkanes in MFI- and MOR-Type Zeolites

Diffusion in sodium mordenite

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