Monte Carlo Study of the Effect of Pressure on Hydrophobic Association
| Autor: | Ronald M. Levy, and Lynne Reed Murphy, Nobuyuki Matubayasi, Vilia Ann Payne |
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| Rok vydání: | 1997 |
| Předmět: | |
| Zdroj: | The Journal of Physical Chemistry B. 101:2054-2060 |
| ISSN: | 1520-5207 1520-6106 |
| DOI: | 10.1021/jp962977p |
| Popis: | This paper describes a series of simulations using pressure as a tool to study the hydrophobic interaction between two simple solutes. The change in the free energy of association (ΔΔGr) of the solutes as a function of pressure is expressed in terms of the change in partial molar volume (ΔV°) and the change in isothermal compressibility (Δκ°) of the system. At 30 °C, ΔV° is found to be −7.4 ± 1.1 mL mol-1, and Δκ° is found to be (−1.4 ± 0.3) × 10-3 mL mol-1 bar-1. The two effects are in opposition to each other: The volume term tends to favor solute association, while the compressibility term favors dissociation. The volume term is the dominant one in determining ΔΔGr at moderate pressures. At higher pressures (above 5 kbar), the opposing effect becomes dominant. A new analysis of experimental data concerning pressure-dependent effects in the association constants for a series of carboxylic acids (Suzuki, K.; Taniguchi, Y.; Watanabe, T. J. Phys. Chem. 1973, 77, 1918−1922) lends support for these conclusi... |
| Databáze: | OpenAIRE |
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