The solubility of oxygen in organic solvents was estimated from property3property correlations.Data on the solubility of gases (in particular, oxygen) in liquids are very important, as they are required for designing and carrying out diverse processes, and also for developing blood substitutes for medicine. The solubility of gases was the subject of numerous papers (see, e.g., [2, 3] and references therein). Despite development of the main theoretical principles of the solubility of gases in liquids, in most cases it is impossible to predict it reliably and accurately.When searching for quantitative structure3property relationships for properties of compounds of different classes (in particular, of organic solvents), it is necessary to know for each class of compounds the parameters describing the contributions of structural fragments (functionally significant groups). If it is necessary to estimate a property for compounds of different classes (as in the case of the solubility of a gas in different solvents), this approach loses sense, because the number of parameters becomes equal to the number of compounds concerned. In this case, instead of a structure3property correlation, it is appropriate to use a property3property correlation, since the [reference] properties through which the properties of interest will be expressed reflect the differences in the parameters for compounds of different classes [4].Here we show that a property3property correlation can be used for estimating the solubility of oxygen in various solvents from the boiling points, heats of vaporization (DH vap ), surface tensions (g), and polarizabilities (a) of the solvents.The transfer of molecules from the gas phase into a solvent can be considered as a sequence of the following steps [3]: formation of a cavity in the solvent, transfer of a gas molecule into the cavity with its involvement in the interaction with the solvent, and ÄÄÄÄÄÄÄÄÄÄÄÄ 1 For communication XXII, see [1]. reorganization (relaxation) of the medium to the equilibrium state.In the physicochemical sense, the free energy of the cavity formation DG cav is the energy of formation of a new surface S sur . In a simple approximation,where g is the surface tension of the solvent and S sur is the surface area of the cavity. As we consider the solubility of the same gas in different solvents, we can assume S sur ; const and replace it by a parameter k 1 . If a gas molecule is comparable in size with solvent molecules, DG cav should be close to DH vap . However, in the overwhelming majority of cases the gas molecules strongly differ in the size from the solvent molecules, and for rough estimates we can assume DG cav = k 2 DH vap , with k 2 being associated with the size ratio of the gas and solvent molecules; however, we will assume k 2 ; const. Both g and DH vap are determined by intermolecular interactions in the solvent. These parameters correlate with each other, but their changes in a set of solvents somewhat differ; therefore, for more accurate estimation of DG cav , we will use...
