Predicting the ionicity of ionic liquids in binary mixtures based on solubility data

• Type: Article in International Scientific Journal
• Date: 2023

Authors

Maria Eugénia Macedo (Author) FEUP; Pedro Velho (Author) FEUP; Catarina Lopes (Author) FEUP

Journal

Title: Fluid Phase Equilibria

Vol. 567 No. 113717

ISSN: 0378-3812

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 0 Citations

ISI Web of Science

Scopus

Scientific classification

CORDIS: Technological sciences

FOS: Engineering and technology

Other information

Authenticus ID: P-00X-RGM

DOI: 10.1016/j.fluid.2022.113717

Abstract (EN): Ionic liquids (ILs) are ionic compounds which are liquid at room temperature and pressure, and can be applied in many fields, such as industrial synthesis, catalysis, electrochemistry, and liquid-liquid separations. To enhance the description of mixtures containing ILs and, consequently, to allow a more rigorous evaluation of the feasi-bility of chemical processes, it is important to study properties such as the ionicity (alpha) of ionic liquids, i.e., the fraction of dissociated molecules. However, experimental determinations of ionicity (also known as dissociation degree or dissociation extent) are time-consuming and require the handling of expensive equipment, so the prediction of this property as a function of the system's composition using thermodynamic modelling is of great relevance. For that purpose, the UNIversal QUAsi-Chemical (UNIQUAC) model was combined with the Pitzer-Debye-Huckel (PDH) equation, which is often referred as PDH+UNIQUAC, and it was used to predict the ionicity of ILs in binary mixtures based on liquid-liquid equilibria (LLE) data. The results were compared with the available experimental data from literature and low deviations were observed, validating thereafter the devel-oped approach. In total, the IL ionicity was predicted, as function of composition, for fourteen ionic liquid / solvent (water or 1-butanol) binary systems. Further, a sensitivity analysis was performed to evaluate the in-fluence of the LLE uncertainties on ionicity (alpha), and it was concluded that alpha was not significantly affected by small deviations, for which the methodology proposed in this work was considered robust. The prediction of IL ionicity with composition using PDH+UNIQUAC thermodynamic modelling was considered a breakthrough, since very accurate results were achieved without the need of undergoing complex experiments.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8