ISSN:
1572-8927
Schlagwort(e):
1-Fluoroalkanes
;
excess enthalpy
;
DISQUAC group contribution model
;
fluoroalkane-solvent interactions
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Chemie und Pharmazie
Notizen:
Abstract Molar excess enthalpies H E at 298.15 K and atmospheric pressure were determined for 12 binary liquid mixtures, 1-fluoropentane, 1-fluorohexane, or 1-fluorononane + a non-polar solvent (hexane, cyclohexane, benzene, or tetrachloromethane) and were interpreted by the DISQUAC group contribution model. 1-Fluoroalkane + n-alkane mixtures are characterized by two types of groups or contact surfaces, fluorine (F) and alkane (CH3, CH2), the remaining mixtures by the additional contact surfaces of the solvents (C6H12 C6H6, or CCl4). The interchange energies, entirely dispersive, of the alkane-solvent contacts were determined independently from the study of solvent-alkane mixtures. The dispersive F-alkane parameters were assumed to equal the parameters of perfluoroalkanes + n-alkanes. The shape of the H E curves of 1-fluorolkane + polarizable solvent (C6H6, CCl4) mixtures are best reproduced by the model when the quasi-chemical F-solvent parameters are assumed to equal zero. The quasi-chemical F-alkane (the same for n-alkanes and cyclohexane) and the dispersive F-solvent parameters were estimated in this work. The 1-fluoroalkane solutions in C6H6 or CCl4 exhibit the characteristic features of polar solute + polarizable solvent mixtures, viz., the deviations from the ideality are less positive than in alkanes and the experimental H E curves are strongly asymmetrical.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00651636
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