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.