Thermodynamics of fluorocarbon–hydrocarbon mixtures. The systems formed by 2,2,4-trimethylpentane with hexafluorobenzene and with hexafluorobenzene–benzene

Abstract

The excess volume of hexafluorobenzene (C₆F₆)–2,2,4-trimethylpentane (2,2,4-TMP) has been measured at 298.15 K as well as the vapour pressures at 298.15, 323.15 and 348.15 K. From the latter, the excess Gibbs energies have been calculated, and the excess enthalpies have been estimated through the Gibbs–Helmholtz equation. The comparison with similar data for binary systems involving benzene (C₆H₆), C₆F₆, 2,2,4-TMP and cyclohexane (c-C₆H₁₂) shows that c-C₆H₁₂ and 2,2,4-TMP have quite different volumetric and entropic behaviours when mixed with C₆F₆, whilst they are almost equivalent when mixed with C₆H₆. Finally, the vapour pressures have been measured and the excess Gibbs energies calculated at 298.15 and 323.15 K for the ternary system C₆F₆–C₆H₆–2,2,4-TMP.