Configurational entropy effects during sorption of hexane isomers in silicalite

被引:45
作者
Calero, S [1 ]
Smit, B [1 ]
Krishna, R [1 ]
机构
[1] Univ Amsterdam, Dept Chem Engn, NL-1018 WV Amsterdam, Netherlands
关键词
configurational-bias Monte Carlo simulations; hexane isomers; ternary mixture;
D O I
10.1006/jcat.2001.3293
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Santilli (J. Catal. 99, 335-341, 1986) has presented experimental data for sorption of hexane isomers, n-hexane (n-C-6), 3-methylpentane (3MP), and 2,2-dimethylbutane (22DMB), in various zeolites. The experimental data on the loadings of the isomers at various temperatures using silicalite are particularly intriguing; 3MP and 22DMB are both seen to exhibit maxima in the sorption loadings with increasing temperature. We rationalise the experimental results by performing configurational-bias Monte Carlo simulations of sorption isotherms at various temperatures and pressures. While the linear n-C-6 can locate at either the straight or zigzag channels, configurational effects make the branched isomers locate only at the intersections. At a total mixture loading of four molecules per unit cell, all the intersections are fully occupied. Both branched isomers 3MP and 22DMB demand an extra "push" to locate within the channel interiors. Configurational entropy effects cause these branched isomers to be progressively "replaced" by n-C-6 in order to achieve higher mixture loadings. The net result is that the branched isomers exhibit maxima at a total mixture loading of four molecules per unit cell. We discuss how configurational entropy effects can be exploited to separate hexane isomers wit high selectivities. (C) 2001 Academic Press.
引用
收藏
页码:395 / 401
页数:7
相关论文
共 12 条
  • [1] Chen N. Y., 1994, MOL TRANSPORT REACTI
  • [2] Dandekar H., 2000, United States Patent No, Patent No. 6069289
  • [3] Chromatographic study of adsorption of n-alkanes on zeolites at high temperatures
    Denayer, JF
    Baron, GV
    Martens, JA
    Jacobs, PA
    [J]. JOURNAL OF PHYSICAL CHEMISTRY B, 1998, 102 (17): : 3077 - 3081
  • [4] Separations of cyclic, branched, and linear hydrocarbon mixtures through silicalite membranes
    Funke, HH
    Argo, AM
    Falconer, JL
    Noble, RD
    [J]. INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, 1997, 36 (01) : 137 - 143
  • [5] Separation of hexane isomers through nonzeolite pores in ZSM-5 zeolite membranes
    Gump, CJ
    Noble, RD
    Falconer, JL
    [J]. INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, 1999, 38 (07) : 2775 - 2781
  • [6] HAIZMANN RS, 1993, Patent No. 5043525
  • [7] Sorption-induced diffusion-selective separation of hydrocarbon isomers using silicalite
    Krishna, R
    Smit, B
    Vlugt, TJH
    [J]. JOURNAL OF PHYSICAL CHEMISTRY A, 1998, 102 (40) : 7727 - 7730
  • [8] Permeation of hexane isomers through an MFI membrane
    Matsufuji, T
    Watanabe, K
    Nishiyama, N
    Egashira, Y
    Matsukata, M
    Ueyama, K
    [J]. INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, 2000, 39 (07) : 2434 - 2438
  • [10] Separation of alkane isomers by exploiting entropy effects during adsorption on silicalite-1: A configurational-bias Monte Carlo simulation study
    Schenk, M
    Vidal, SL
    Vlugt, TJH
    Smit, B
    Krishna, R
    [J]. LANGMUIR, 2001, 17 (05) : 1558 - 1570