THERMODYNAMICS OF SOLUTIONS WITH LIQUID-CRYSTAL SOLVENTS .9. GAS-LIQUID-CHROMATOGRAPHIC STUDY OF NON-MESOMORPHIC SOLUTES IN NEMATIC AND ISOTROPIC N-(PARA-METHOXYBENZYLIDENE)-PARA'-NORMAL-BUTYLANILINE AND PARA-NORMAL-PENTYL-PARA'-CYANOBIPHENYL

被引:67
作者
OWEIMREEN, GA [1 ]
LIN, GC [1 ]
MARTIRE, DE [1 ]
机构
[1] GEORGETOWN UNIV,DEPT CHEM,WASHINGTON,DC 20057
关键词
D O I
10.1021/j100479a012
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
Thermodynamic results from gas-liquid chromatography (GLC) are reported for 20 nonmesomorphic solutes in the nematic and isotropic liquid phases of the two solvents N-(p-methoxybenzylidene)-p′-n-butylaniline (MBBA) and p-n-pentyl-p′-cyanobiphenyl (5CB), both of which exhibit room-temperature nematic phases. The infinite-dilution solute activity coefficients, partial molar excess enthalpies and entropies, and partial molar enthalpies and entropies of solution are examined within the framework of statistical-thermodynamic models. Discernible trends and differences in behavior between the two solvents, between the two phases, among the different solute groups (n-alkanes, branched alkanes, and aromatics), and within a given solute group are discussed and, where justifiable, are interpreted, with special emphasis on the effects of solute size, shape, and flexibility. The analytical implications of this study, i.e., shape-selective GLC separation of geometric isomers, are investigated. Also, a novel method, combining GLC and calorimetry, for generating phase diagrams (nematic-isotropic equilibria) for mixtures of nonmesogenic solutes at low concentration in mesogenic solvents is further developed and successfully applied. © 1979 American Chemical Society.
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页码:2111 / 2119
页数:9
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