(595f) Predicting the Phase Behavior of Charged and Polar Fluids Using the SAFT-VR+DE Approach

Knowledge of the thermodynamic behavior of charged and polar systems is essential for the design and development of many important chemical, biological and environmental processes and has resulted in an increasing demand for predictive tools that accurately describe the thermodynamic behavior of such systems. It is the industrial importance and well known non-ideal thermodynamic behavior of these systems that has lead to increasingly intense academic research and the development of molecular based tools. Traditionally, the description of thermodynamic behavior has been obtained through macroscopic theories that are based on phenomenological equations containing adjustable parameters that lack physical meaning. In this regard, molecular-based equations of state, such as the statistical associating fluid theory (SAFT) [1], which are able to describe the thermodynamic behavior of fluids using adjustable physically based parameters, can be considered a powerful tool to describe the thermodynamics of complex systems. In a recent series of extensions to the SAFT-VR equation of state, McCabe and coworkers [2] have incorporated the different electrostatic interactions (ion-ion, ion-dipole and dipole-dipole) using the mean spherical approximation of Blum et al.[3] with the non-primitive model to account for the solvent molecules explicitly in the so-called SAFT-VR+DE equation. In this work, we apply the SAFT-VR+DE approach to deal with pure fluids and mixtures of charged and polar fluids, such as electrolytes, mixed polar solvent electrolytes and ionic liquids.

[1] W. G. Chapman, K. E. Gubbins, G. Jackson, and M. Radosz, Fluid Phase Equilibria 52, 31 (1989); W. G. Chapman, G. Jackson, and K. E. Gubbins, Molecular Physics 65 (5), 1057 (1988).

[2] H. Zhao and C. McCabe, Journal of Chemical Physics 125, 104504 (2006); H. Zhao, Y. Ding, and C. McCabe, Journal of Chemical Physics 127, 084514 (2007); H. Zhao, M. C. dos Ramos, and C. McCabe, Journal of Chemical Physics 126, 244503 (2007).

[3] D. Wei and L. Blum, Journal of Chemical Physics 87 (5), 2999 (1987); L. Blum and D. Q. Wei, Journal of Chemical Physics 87 (1), 555 (1987).