Thermodynamic properties of binary systems containing hexafluorobenzene. Part 2.—Excess volumes of mixing and dipole moments

Abstract

The excess volume of mixing as a function of composition has been measured at 40°C for mixtures of hexafluorobenzene with eight hydrocarbons, cyclohexane, cyclohexene, 1,3-cyclohexadiene, benzene, toluene, p-xylene, mesitylene, and cumene. The results indicate that the fluorocarbon forms complexes with the hydrocarbons to an increasing extent as the electrondonating power of the hydrocarbon is increased. In an attempt to elucidate the nature of the complexing, the dipole moment of hexafluorobenzene has been measured in solutions of cyclohexane, benzene, p-xylene and mesitylene. The results are inconclusive but it is probable that any intermolecular bonding due to charge transfer interaction is extremely weak.