(204d) Triangular-Well Fluid Equation of State: Extension to Mixtures

In this study, it is shown that the triangular-well (TW) fluid analytic equation of state (EOS) proposed by Betancourt-Cárdenas et al. [Mol. Phys. 105 (2007) 2987 and Mol. Phys. 106 (2008) 113] based on the perturbation theory by Barker-Henderson can be applied to binaries mixtures. The TW potential is more realistic than the well-know square-well (SW) potential besides it has an analytical simplicity, which shows a great potential to be used for the molecular based equations of state as it can be observe in the followings works Zhou [J. Chem. Phys. 130 (2009), 014502], Koyuncu [Mol. Phys. 109 (2011), 565] y Rivera et al. [Mol. Phys. 110 (2012), 1317 ]. The formulation by Betancourt-Cardenas used a second order perturbation theory with a macroscopic compressibility approximation. We present vapour–liquid phase diagrams and thermodynamic properties such as the density as a function of the pressure at different temperatures and for several values of the potential range, for different mixtures of alkanes-alkanes and carbon dioxide-alkanes reported in the literature. The classic van der Waals mixture rules are used. The preliminary results are auspicious of good agreement with data reported in the literature.