Thermodynamics of Liquid Mixtures of Xenon with Alkanes:  (Xenon + n-Butane) and (Xenon + Isobutane)

The total vapor pressure of liquid mixtures of (xenon + n-butane) has been measured at 182.34 and 195.49 K, and of (xenon + isobutane) at 195.49 K. The liquid molar volumes have also been measured at 182.34 K for both systems. The mixtures follow the behavior already found for other (xenon + alkane) mixtures, i.e., negative deviations from Raoult's law, negative excess molar Gibbs energies ( ) and negative excess molar volumes ( ). The excess molar enthalpy ( ) is approximately zero in the case of (xenon + n-butane). The results were interpreted using the statistical association fluid theory for potentials of variable attractive range (SAFT-VR). This study provides further evidence that the (xenon + n-alkane) mixtures can be thought of as a particular case of mixtures of n-alkanes.