Solubility of gases in mixed solvents

The solubilities of gases in binary, ternary or more complex multicomponent solvents are good examples in which the Kirkwood–Buff theory of solutions provides excellent results that cannot be obtained using the methods of traditional thermodynamics. Thermodynamics cannot provide explicit pressure, temperature, and composition dependence of the thermodynamic functions, such as the activity coefficients of the components. Therefore, various assumptions regarding the activity coefficients must be made. In contrast, the Kirkwood–Buff theory of solution allows one to establish, in some cases, relations between multicomponent and binary mixtures (see 3.5). Although these relations are not simple, they could be applied to ternary (3.1–3.4) and quaternary (3.5) mixtures to derive relations for the activity coefficients.

3.1 Henry’s constant in mixed solvents from binary data.

3.2 Salting-out or -in by fluctuation theory.

3.3 The solubility of binary mixed gases by the fluctuation theory.

3.4 Prediction of the solubility of gases in binary polymer + solvent mixtures.

3.5 Ideal multicomponent liquid solution as a mixed

solvent.

3.6 Solubility and local structure around a dilute solute molecule in an aqueous solvent: From gases to biomolecules.