Comparison of a low transition temperature mixture (LTTM) formed by lactic acid and choline chloride with choline lactate ionic liquid and the choline chloride salt: physical properties and vapour–liquid equilibria of mixtures containing water and ethanol

A new group of nature-based solvents, i.e. low transition temperature mixtures (LTTMs), are evaluated in this work as entrainers for the separation of azeotropic mixtures. The effect of choline-based LTTMs on the vapour pressure of ethanol and water is compared to the effect of the corresponding lactate-based choline salt and a chloride-based choline salt. The changes with temperature and composition of the physical properties ( density and viscosity) of the binary mixtures (entrainer + water-ethanol) are studied and compared. Also, the vapour-liquid equilibrium (VLE) data for binary mixtures of water-ethanol with the studied entrainers are reported. The phase diagrams of the ternary systems composed of water + ethanol + entrainer are shown and the experimental data are correlated by using the e-NRTL model.