Determining the dissociation extent of ionic liquids in water using the PDH + UNIQUAC model

Abstract

The main goal of this work was to find a novel way of qualitatively determining the dissociation extent of ionic liquids (ILs) in water, based only on thermodynamic models. The UNIversal QUAsi-Chemical (UNIQUAC) model was applied separately (to account for short-range interactions and considering only neutral molecules) and coupled with the Pitzer-Debye-Hückel (PDH) equation (to account for long-range interactions) to binary temperature-composition data (Txx). For calculating the closest approach parameter (ρ), which appears in the PDH equation, a new method was developed considering the ionic radii and solvation. This novel strategy, which considers that ILs may dissociate and accounts for the dissociation extent, allows the description of systems containing these compounds more accurately, which is a very useful tool for both academia and industry.