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  • methanol  (3)
  • 18-crown-6-ether  (1)
  • Gurney cosphere  (1)
Materialart
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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Journal of solution chemistry 19 (1990), S. 1211-1224 
    ISSN: 1572-8927
    Schlagwort(e): Hydrochloric acid ; water-tetrahydrofuran ; water-dioxane ; water-dimethoxyethane ; conductance ; association constants ; proton mobility ; Gurney cosphere
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Conductance of dilute solutions of HCl in water-tetrahydrofuran (THF), water-dioxane and water-dimethoxyethane (DME) were measured and the data processed using the Justice-Ebeling equation to evaluate the limiting conductance ΛO, the association constant KA and the apparent distance of closest approach a'. The Friedman-Rasaiah Gurney cosphere overlap term d+−/kT was calculated from a' values and illustrates the different solvation pattern of dioxane compared to that found for THF and DME. It would appear that dioxane can solvate cations more strongly due to its ability to form a boat configuration around a cation. The association constants are reasonably reproduced by the Bjerrum equation using realistic molecular dimensions of the ions involved for the distance of closest approach. The limiting conductance in the mixtures illustrates clearly the different mechanism for proton conductance compared to that for the cesium ion. The dielectric constants, viscosities and densities of the solvent mixtures were measured and are reported. The lowest dielectric constant for each type of solvent mixture was about 10.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Journal of solution chemistry 20 (1991), S. 1001-1016 
    ISSN: 1572-8927
    Schlagwort(e): 18-crown-6-ether ; dibenzo-18-crown-6-ether ; apparent molar volume ; partial molar volume change on complex formation ; methanol ; acetonitrile ; dimethylsulfoxide
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract The apparent molar volumes of equimolar concentrations of 18-crown-6-ether (CE) or dibenzo-18-crown-6-ether (B2CE) and MCl (M=Na, K, or Cs) or MI in dilute solutions of anhydrous methanol, acetonitrile and dimethylsulfoxide have been calculated from density data measured at 25°C. After extrapolation to infinite dilution these results together with the apparent molar volumes of the crown ethers and the alkali metal halides were used to calculate the limiting partial molar volume change for the formation of the complexes. By noting that the charge of the complexed cation has been shown to be completely shielded from the solvent, the volume of complexation can be assumed to be a good estimation of the volume change due to electrostriction of the solvent by the cationic charge. The results are compared to the predictions of the Hepler equation.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Journal of solution chemistry 4 (1975), S. 299-310 
    ISSN: 1572-8927
    Schlagwort(e): Dielectric constant ; ethanol ; high pressure ; Kirkwoodg K factors ; liquid association ; methanol ; n-propanol
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Precise static dielectric constants are reported for methanol, ethanol, andn-propanol at 10,25, and 40° C and at pressures up to 3 kbar. The measurements were carried out by a low-frequency bridge method using a threeterminal, all-glass cell. An uncertainty of 0.05% is claimed for the data. The results are compared to data from previous investigations, whith the agreement in the absolute magnitude poor but the agreement in the pressure coefficient reasonable in most cases. The data are analyzed in terms of the Kirkwood correlation factorg K as obtained from the Fröhlich equation. In all cases, theg K factor decreases with increased pressure. The problems involved in calculating this factor from the experimental data are discussed, and it is shown that the trends ing K are very dependent upon the assumptions made in isolating the liquid dipole moment from its gas-phase value. This fact also indicates that an interpretation of theg K values in terms of stepwise association of correlation dipoles is premature at this time.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Journal of solution chemistry 2 (1973), S. 23-35 
    ISSN: 1572-8927
    Schlagwort(e): methanol ; moving boundary ; transference numbers ; LiCl ; NaCl ; KCl ; Bu4NBr ; ion-pair association constants ; electrophoretic effect
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Transference numbers are reported for LiCl and NaCl in methanol at 25°C and for NaCl, KCl, and Bu4NBr in methanol at 10°C. The potentiometric moving-boundary method as developed by Kay and Fratiello was employed to give a precision of about 0.05% and an accuracy of at least 0.1% as indicated by two independent determinations of the conductances of the Cl− and Br− ions. The data are extrapolated by the Fuoss-Onsager theory, and the magnitude of the electrophoretic effect is calculated as described by Kay and Dye. The agreement with this theory is quite good at both temperatures, although the å value required in the case of Bu4NBr is considerably larger than that obtained from conductance data. This agreement contrasts with that obtained for ethanol and acetone solutions where the measured electrophoretic effect is considerably larger than the corresponding calculated values. The importance of this fact in the determination of ion-pair association constants is discussed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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