The experimental study on the (solid + liquid) phase equilibria for {LiBr (1) + ionic liquid (2) + water (3)} systems

The paper presents experimentally determined (solid + liquid) phase diagrams in the {LiBr (1) + ionic liquid (2) + water (3)} systems. Interpretation of the results and comparison with the literature data for the {LiBr + water} enables the determination of the influence of the ionic liquid on the LiBr solubility in water. It is known that one of the disadvantages of an aqueous lithium bromide solution is the tendency to crystallize, especially with a higher concentration of lithium bromide in the solution. This is one of the problems in absorption refrigeration technology where the aqueous lithium bromide solution is a working fluid commonly used on an industrial scale. One of the possibilities for improving the properties of this system is the use of an additive increasing the solubility of LiBr in water. In this work, the following ionic liquids (ILs): N-(2-hydroxyethyl)ammonium glycolate, N,N-di(2-hydroxyethyl)ammonium glycolate, N,N-di(2-hydroxyethyl)-N-methylammonium glycolate, and N,N,N-tri(2-hydroxyethyl)-ammonium glycolate were considered as an addition to the conventional system. The (solid + liquid) phase diagrams were determined using the dynamic method. Liquid phase range was determined at the absorber operating temperature, T = 303.15 K, and compared to LiBr + water system.