Browsing by Author "Dickinson, Eric"

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Thermodynamics of n-alkane + dimethylsiloxane mixtures: Part 1.—Gas–liquid critical temperatures and pressures
(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1974, 70 (12), 1974) Dickinson, Eric; McLure, Ian A.
Gas–liquid critical temperatures Tcm have been determined for four mixtures: (i) n-hexane + hexamethyldisiloxane, (ii) n-octane + hexamethyldisiloxane, (iii) n-octane + octamethyltrisiloxane, and (iv) n-octane + 2,2,4,4-tetramethylpentane. Using a statistical model based upon the van der Waals one-fluid approximation, values of Tcm for each mixture are related to a parameter ζ which is proportional to the energy of interaction between the unlike molecular species. Gas–liquid critical pressures pcm are reported for mixtures (i), (ii) and (iii), and the results are discussed in terms of possible deviations from the Lorentz combining rule of collision diameters.
Thermodynamics of n-Alkane+Dimethylsiloxane Mixtures: Part 3.—Excess Volumes
(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1974, 70 (12), 1974) Dickinson, Eric; McLure, Tan A.
Excess volumes have been measured dilatometrically for binary mixtures of six n-alkancs (n- pentane, n-hexane, n-heptane, n-octane, n-dccane and n-tetradecanc) with four linear dimethylsiloxanes (dimer, trimer, tetramer and pentamer) at 303.2 K, and for four other mixtures. The sign and magnitude of the excess volumes depend intimately upon the chain lengths of the oligomers. The phenomenological corresponding states theory of Patterson is shown to reproduce qualitatively the experimental chain length dependence. Suggestions for the success of the model arc discussed briefly in terms of the properties of the pure components, and the disadvantages of two other approaches —the van der,Waals one-fluid model and the Prigogine cell theory—are identified. An application of Bransted’s principle of congruence to ternary mixtures is discussed.
Thermodynamics of n-Alkane+Dirnethylsiloxane Mixtures: Part 2.—Vapour Pressures and Enthalpies of Mixing
(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1974, 70 (12), 1974) Dickinson, Eric; McLure, Ian A.; Powell, Bernard H.
The total vapour pressures of mixtures of n-hexane and hexamethyldisiloxane have been measured by a static equilibrium method at 303.15, 309.15 and 315.15 K. At each temperature the derived equimolar excess Gibbs free energy is small and positive. The excess enthalpy at 298.15 K, as determined by direct calorimetry, has a skew-parabolic composition dependence and a positive equimolar value of 126 ± 2 J mol–1. Theoretical excess functions for n-hexane + hexamethyldisiloxane are calculated from a one-fluid van der Waals model in conjunction with an experimental pure liquid reference substance; they agree well with experiment.