On the use of the Weeks–Chandler–Andersen theory for interpreting the solubilities of gases in liquids

Abstract

The Weeks–Chandler–Andersen liquid state perturbation theory was corrected for translational quantum effects in the liquid, and was then used as the basis for the derivation of a fundamental solubility theory. Equations were derived for the Henry’s law constant K, the heat of solution of a solute in a solvent at infinite dilution ΔHs⋅ and the partial molar volume of a solute in a solvent of infinite dilution, ?2⋅. The equations were applied, over a range of temperatures, to the following systems: H2 in each of Ar, N2, CH4; He in each of Ar, N2, CH4; Ne in each of Ar, N2. Lennard-Jones 6–12 pair potentials, taken from second virial coefficient data were used. The results obtained were compared with experimental data, and with previous calculations on these systems that were based on the Leonard–Henerson–Barker and the Mansoori–Canfield–Leland theories. The Weeks–Chandler–Andersen results were, for most of the systems, in very good agreement with the experimental results and, for most of the systems, the Weeks–Chandler–Andersen predictions for K were better than those that came from either the Leonard–Henderson–Barker theory or the Mansoori–Canfield–Leland theory.