Browsing by Author "Franks, Felix"

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Solute Interactions in Dilute Aqueous Solutions Part 4.—Microcalorimetric Study of Ternary Mixtures of Urea and Hydrophobic Species
(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1981, 77 (06), 1981) Franks, Felix; Pedley, Michael D
Heats of dilution of urea, acetone, ethylmethyl ketone and tetrahydrofuran, and heats of mixing of urea with each of the other solutes have been measured at 25°C; the urea + acetone system was also studied at 5°C. The various enthalpic pair and triplet interaction coefficents, hij, hijj, etc. have been evaluated. The hii for the ketones and THF are positive and show a dependence on the alkyl chain length typical of the hydrophobic pair interaction, while for urea hii is negative. The cross coefficients hij are small, but positive. The triplet coefficients are generally small and of variable sign. At 5°C, all the coefficients are of a greater magnitude. The results are discussed in terms of various models for aqueous solutions of urea.
Solute interactions in dilute aqueous solutions. Part 3.—Volume changes associated with the hydrophobic interaction
(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1977, 73 (05), 1977) Franks, Felix
Second virial coefficients in the excess volume equation have been evaluated for BuOH, BuiOH, BusOH and ButOH in dilute aqueous solution at several temperatures. The coefficients are negative and decrease in magnitude with rising temperature. They are compared with predicted values based on the model for the hydrophobic interaction.
Solute Interactions in Dilute Solutions Part 2: A Statistical Mechanical Study of the Hydrophobic Interaction
(Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1977, 73 (2), 1977) Clark, Alan H.; Franks, Felix; Pedley, Michael D.; Reid, David S.
The aqueous solution properties of aliphatic alcohols have been analysed in terms of pairwise hydrophobic interactions. The potential of average force hz(r) was obtained as the sum of the vacuum potential U(r), calculated by a Monte Carlo method, and a simple solvent free energy A(r). Using published osmotic coefficient data, it has been found unexpectedly that the well depth of JF(r) is shallower than that of U(r'). The pair correlation function g(r), obtained from Hz(r) by the hypernetted chain approximation has been used to derive the energy, entropy and volume changes associated with the hydrophobic interaction. The results are not compatible with the conventional model of the hydrophobic association. Alternative models are discussed and the results are compared with those from earlier theoretical treatments.