Fluid Phase Equilibria, Vol.95, 371-381, 1994
Influence of Molecular Shape on Vapor-Liquid-Equilibria - Application of a Modified Christoforakos-Franck Equation of State
The Christoforakos-Franck equation of state, originally derived for spherical molecules, is modified to account for deviations from spherical geometry. The contribution from repulsive interactions is obtained from the Boublik-Nezbeda model for the compressibility of hard bodies of arbitrary shape. The deviation from sphericity (alpha) is deduced from the hard convex body model of molecular geometry. Attractive intermolecular interactions are characterized by the depth (- epsilon) and relative width (lambda) of a square-well potential. The influence of molecular shape on the vapour-liquid equilibrium properties of pure fluids is investigated by using the modified equation to predict the vapour pressure of non-spherical molecules. It is concluded that incorporating molecular shape in the conventional equation of state methodology does not significantly influence the quality of the predicted vapour-liquid equilibria.
Keywords:GENERALIZED VANDERWAALS-EQUATION;BINARY FLUID MIXTURES;THERMODYNAMIC PROPERTIES;HIGH-TEMPERATURES;HIGH-PRESSURES;N-DECANE;HYDROCARBONS;POINT