Solubility and entropy of solution of gases in CCl2F.CClF2

Abstract

We determined the solubility and entropy of solution of Ne,H₂, Xe, C₂H₆ and C₂F₆ in the Freon, CCl₂F.CClF₂, over ranges of approximately 25°C. A plot of the entropy of solution against R In x₂ for these gases and four others determined earlier in this laboratory gives a straight line close to and nearly parallel to the line for gases in cyclohexane. These lines and the lines for gases in other solvents from fluorochemicals to carbon disulphide constitute a family converging approximately at an intercept of –21 cal/deg. mol at R In x₂= 0. This is explained as the result of replacing solvent by a succession of gases of increasing solubility ending with an hypothetical liquid which boils at 25°C and 1 atm with an entropy of 21.0 cal/deg. mol.

When RT In x₂ for these gases is plotted against the molal energies of vaporization of the gases at their boiling points, distinct straight lines are found for several groups of gases. One of these groups contains H₂, CH₄, and C₂H₆, whose molecules, together with those of other alkanes, contain no non-bonded outer electrons. The same correlation occurs in six other solvents.