Perfluorocarbons compressibility

Highly fluorinated molecules have a nonpolar character and an extremely low polarizability, inducing only weak intra- and intermolecular interactions. As a consequence, perfluorocarbons behave almost like ideal liquids they are very compressible and have very high vapor pressure. For example, the physical properties of perfluoro-hexane, heptafluorohexane, and hexane are reported in Table 1.2 The effect of the polar character of the hemifluorinated compound (heptafluorohexane) on the dielectric constant value is remarkable. 

Recent applications of the theory have been made for calculating the contribution the formation of a cavity gives to the free energy of transfer of a series of isomeric ketones(134), or various other solutes(132), from H2O to D2O, for the studies of solubility of many apolar gases in water and other polar solvents(135), for comparing the experimental thermodynamic data for the solution of rare gases(51), or some perfluorocarbon gases(136), in water at various temperatures with data calculated by means of the SPT. In a tentative made to extend the theory at aqueous solutions where solute-solute interactions have to be considered and hydrophobic interactions are operative, it has been shown that the dependence of the partial molar volumes and enthalpies of hard-sphere solutes in water on concentration and temperature are due to the anomalous trends the 63/6P and 63/6T (3 coefficient of isothermal compressibility) of pure water present, rather than to the solute structural effects(137). 

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