Modeling Binary Mixtures of Water plus Light Hydrocarbon Using the Perturbed-Chain Statistical Associating Fluid Theory with Induced Association: Improvement in Describing All Equilibrium Phases

Hydrophobic effects, including low mutual solubilities, are well-documented between water and hydrocarbons. However, as deduced from quantum chemical calculations and molecular simulations, an attractive interaction as a result of electrostatic interactions and induction by water on hydrocarbon molecules exists and must be included to adequately model water-hydrocarbon systems. As shown in this work, the inclusion of these interactions allows for the perturbed-chain statistical associating fluid theory equation of state (EOS) to perform well in all equilibrium phases. Without these corrections, the EOS usually performs well only for the phase used for parametrization. Because the EOS will also be used in near-freezing water temperatures, the parameters of water are carefully derived to be able to reproduce the density anomaly of water and behavior when extrapolated to the supercooled region. The improvements and calculations will be useful for the assessment of the occurrences of potentially habitable water-poor and water-rich environments within the ice crusts and rocky crusts of extraterrestrial bodies.