Thermodynamic properties of N-octyl pyridinium hexafluorophosphate ionic liquid: Characterization and application in separation of the azeotrope

Abstract

The experimental data of the weight fraction activity coefficient (Ω12∞), the Flory–Huggins interaction parameter (χ12∞), the activity coefficient at infinite dilution (γ12∞) and the Hildebrand solubility parameters (δ2) involving N-octyl pyridinium hexafluorophosphate ([OPY][PF6]) ionic liquid (IL) have been evaluated by Inverse gas chromatography (IGC). The values indicated the interaction of solvents-IL depended on the structure of the solvents and the experimental temperatures. Based on IGC data, the isothermal vapor–liquid equilibrium (VLE) data of solvent-IL at 343.15 K were derived and related to the NRTL model. The acquired binary interaction parameters have a great significance in order to model. The equilibrium phase diagram of the [OPY][PF6]-acetone/chloroform–methanol ternary system was obtained by Aspen Plus simulation. The result showed that the IL can be used as a potential solvent for separating azeotropic mixtures of chloroform (1)/methanol (2) and acetone (1)/methanol (2).