Catalysis by shape selective zeolites-science and technology

Csicsery, Sigmund M.

doi:10.1351/pac198658060841

Cited by 243 publications

(127 citation statements)

References 24 publications

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“…The CBMC method significantly improves the efficiency for sampling of chain-molecule conformations by many orders of magnitude, and its combination with NVT MC and GCMC simulations has been widely used for alkane adsorption, especially, for long alkanes. Smit and Siepmann 22 simulated the adsorption of nC 4 to nC 12 on silicalite, and a linear dependence of the isosteric heat on chain length was found. Maginn et al 23 examined the lowcoverage sorption of normal alkanes from nC 4 to nC 25 on silicalite, and temperature-dependent alkane configurations and locations were found.…”

Section: Introductionmentioning

confidence: 97%

“…But with a proper choice of adsorbents ͑or molecular sieves͒ and operating conditions, alkanes may be separated by competitive adsorption based on the differences in their molecular size and shape. [4][5][6] Over years, numerous experimental studies have been carried out on the adsorption and separation of alkanes on various types of adsorbents. Maciver et al 7 measured the adsorption of lower molecular weight alkanes ͑C 3 , nC 4 and iC 4 ͒ on silica, alumina, and silica-alumina cracking catalysts over the temperature range from 25°to 350°C, and observed physisorption accompanied by chemisorption.…”

Section: Introductionmentioning

confidence: 99%

“…[4][5][6] Over years, numerous experimental studies have been carried out on the adsorption and separation of alkanes on various types of adsorbents. Maciver et al 7 measured the adsorption of lower molecular weight alkanes ͑C 3 , nC 4 and iC 4 ͒ on silica, alumina, and silica-alumina cracking catalysts over the temperature range from 25°to 350°C, and observed physisorption accompanied by chemisorption. Bruce et al 8 determined the gas-solid second virial coefficients for the normal C 3 ,C 4 ,C 5 , and C 6 alkanes on Carbopack C and C-HT in the temperature range of 323 to 471 K, and found that the gassolid adsorption energy has a linear correlation with the boiling point and with the ratio of critical temperature to the square root of the critical pressure.…”

Section: Introductionmentioning

confidence: 99%

“…Maris et al 24 calculated the adsorption isotherms of C 1 to nC 5 in the aluminophosphate AlPO 4 -5, and observed a surprisingly low density-high density transition resembling capillary condensation. Du et al 25 simulated adsorption isotherms of pure C 1 ,C 2 ,C 3 , nC 4 , and their binary mixtures on silicalite. Good agreement with limited available experimental data was obtained, and competitive adsorption in the C 1 -C 2 mixture was observed in which C 2 is preferentially adsorbed at low pressures but this preference reverses at high pressures.…”

Section: Introductionmentioning

confidence: 99%

“…De Meyer et al 34 and Chempath et al 35 presented simulations of the liquid-phase adsorption of linear alkanes and their mixtures on ZSM-5 and silicalite, and good agreement with experimental results was obtained. Düren and Snurr 36 computed the adsorption of C 1 and nC 4 and their mixtures on isoreticular metal-organic frameworks, and the influence of the organic linker molecule on adsorption and selectivity were analyzed. Fox et al 37,38 simulated the adsorption of pure and mixed linear, branched, and cyclic alkanes on silicalite-1, AlPO 4 -5, and ITQ-22, and temperaturedependent adsorption hierarchy and selectivity were found.…”

Section: Introductionmentioning

confidence: 99%

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Adsorption and separation of linear and branched alkanes on carbon nanotube bundles from configurational-bias Monte Carlo simulation

et al. 2005

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The adsorption and separation of linear ͑C 1 -nC 5 ͒ and branched ͑C 5 isomers͒ alkanes on single-walled carbon nanotube bundles at 300 K have been studied using configurational-bias Monte Carlo simulation. For pure linear alkanes, the limiting adsorption properties at zero coverage exhibit a linear relation with the alkane carbon number; the long alkane is more adsorbed at low pressures, but the reverse is found for the short alkane at high pressures. For pure branched alkanes, the linear isomer adsorbs to a greater extent than its branched counterpart. For a five-component mixture of C 1 -nC 5 linear alkanes, the long alkane adsorption first increases and then decreases with increasing pressure, but the short alkane adsorption continues increasing and progressively replaces the long alkane at high pressures due to the size entropy effect. All the linear alkanes adsorb into the internal annular sites with preferred alignment parallel to the nanotube axis on a bundle with a gap of 3.2 Å, and also intercalate the interstitial channels in a bundle with a gap of 4.2 Å. For a three-component mixture of C 5 isomers, the adsorption of each isomer increases with increasing pressure until saturation, though nC 5 increases more rapidly with pressure and is preferentially adsorbed due to the configurational entropy effect. All the C 5 isomers adsorb into the internal annular sites on a bundle with a gap of 3.2 Å, but only nC 5 also intercalates the interstitial channels on a bundle with a gap of 4.2 Å. This work suggests the possibility of separating alkane mixtures based on differences in either size or configuration, as a consequence of competitive adsorption on the carbon nanotube bundles.

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Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Adsorption and separation of linear and branched alkanes on carbon nanotube bundles from configurational-bias Monte Carlo simulation

et al. 2005

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Shape‐Selective Catalysis – Heterogeneous

Csicsery

Kiricsi

2002

Encyclopedia of Catalysis

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Molecular sieves have uniform pores. If the pores are small, the fate of the reactants and the probability of forming products are determined by molecular dimensions and configurations as well as by the types of catalytically active sites present. Reactant shape selectivity occurs when some of the molecules in a reactant mixture are too large to enter the pores. Product selectivity occurs when, among all the product molecules formed within the pores, only those with the proper dimensions can diffuse out and appear as products. In restricted transition state type selectivity certain reactions are prevented because the corresponding transition state requires more space than is available inside the pores. Shape selective processes include acid‐ or base‐catalyzed reactions, oxidations, and reductions. Commercial applications of shape selectivity ( 1 ) form desirable isomers instead of undesirable ones, ( 2 ) crack undesirable molecules to smaller, easily removable fragments, or ( 3 ) avoid undesirable competing reactions such as coking and transalkylation. Ordered mesoporous materials, pillared layer structures, heteropolyacids, and carbon molecular sieves and nanotubes extend shape‐selective application to reactions of molecules too large to fit in the pores of aluminosilicate zeolites. Designing new molecular sieves and modifying existing ones can amplify shape selective effects and thus help to meet future challenges: diminishing raw material supplies, more stringent environmental regulations, changing fuel requirements, and the desire for more flexible, more economical, and environmentally more friendly processes.

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Zeolites and Other Micro- and Mesoporous Molecular Sieves

Treichel

2010

Kirk-Othmer Encyclopedia of Chemical Technology

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Catalysis by shape selective zeolites-science and technology

Cited by 243 publications

References 24 publications

Adsorption and separation of linear and branched alkanes on carbon nanotube bundles from configurational-bias Monte Carlo simulation

Adsorption and separation of linear and branched alkanes on carbon nanotube bundles from configurational-bias Monte Carlo simulation

Shape‐Selective Catalysis – Heterogeneous

Zeolites and Other Micro- and Mesoporous Molecular Sieves

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