Equation of state based on the hole-lattice theory and surface-charge density (COSMO): Part A – Pure compounds

An equation of state (EoS) was proposed using the generalized van der Waals theory (GvdW), augmented with the surface-charge density, σ-profiles from COSMO. This equation is mathematically similar to the Mattedi-Tavares-Castier (1998) equation, but instead of using group contributions, the σ-profiles were used for molecular description. The interaction energy needed to calculate the probability of a contact in the equation of state is similar to the term used in the COSMO-SAC model. For each of the 169 substances studied here, three (3) parameters of the equation were estimated: the lattice cell molar volume (v∗) and two non-electrostatic parameters (C0,NE and C1,NE). Experimental vapor pressures and saturated liquid volumes were used to estimate these parameters and mean relative deviations 2.49% and 7.47% were found for vapor pressure and saturated liquid volume, respectively. It was also performed an analysis of the estimated parameters of some homologous series, resulting in universal functions for for all estimated parameters as function of van der Waals volume (VvdW).