title: Liquid-vapor equilibria of ionic liquids from a SAFT equation of state with explicit electrostatic free energy contributions.
abstract: Statistically associating fluid theory (SAFT) provides closed-form free energies by perturbation methods. We propose here a SAFT equation of state for ionic liquids that models the contribution from Coulomb forces after that of the Restricted Primitive Model (RPM) in the Mean Spherical Approximation (MSA). The resulting SAFT-MSA equation, fitted to simulated orthobaric curves of imidazolium based ionic liquids, predicts experimental density data with errors ≈1% and the characteristic decrease of all critical coordinates with increasing cation size. The SAFT-MSA equation can be applied to calculate thermodynamic coefficients, the speed of sound and surface tension (among other properties) of pure ionic liquids and can be generalized straightforwardly to mixtures.
authors.affiliation: †Departamento de Física, Universidad Autónoma Metropolitana, Iztapalapa, Apdo 55 534, México DF 09340, México.
authors.forename: Orlando
authors.initials: O
authors.lastname: Guzmán
authors.affiliation: †Departamento de Física, Universidad Autónoma Metropolitana, Iztapalapa, Apdo 55 534, México DF 09340, México.|‡Colegio de Ciencia y Tecnología, Universidad Autónoma de la Ciudad de México, México DF 09790, México.
authors.forename: J Eloy
authors.initials: JE
authors.lastname: Ramos Lara
authors.affiliation: †Departamento de Física, Universidad Autónoma Metropolitana, Iztapalapa, Apdo 55 534, México DF 09340, México.
authors.forename: Fernando
authors.initials: F
authors.lastname: Del Río