Liquid-liquid phase separation in binary mixtures of quaternary alkylammonium chlorides with carboxylic acids

We reported the phase separation measurements of mixtures obtained from choline, tetramethylammonium and tetraethylammonium chlorides with methacrylic (MAA), butyric (BA) and isobutyric (IBA) acids as solvents. Liquid-liquid equilibrium (LLE) experiments were performed under atmospheric pressure in a temperature range of 287-403 K using cloud-point method and the data were correlated with the Non-Random Two Liquid (NRTL) solution model. The density, the viscosity, the Kamlet-Taft and the solvent polarity (ET(30)) parameters were measured for coexisting liquid phases. The applicability of the obtained binary biphasic system in extraction process, particularly purification of MAA from a phenolic inhibitor, was demonstrated.

Automated summary

The phase separation of mixtures composed of choline, tetramethylammonium, and tetraethylammonium chlorides with methacrylic, butyric, and isobutyric acids as solvents was investigated. Liquid-liquid equilibrium experiments were conducted under atmospheric pressure and the data were analyzed using the NRTL solution model. Measurements of density, viscosity, Kamlet-Taft parameters, and solvent polarity (ET(30)) were performed for the coexisting liquid phases. The binary biphasic system obtained in this study showed potential for extraction processes, particularly in the purification of methacrylic acid from a phenolic inhibitor.