(Vapor + liquid) phase equilibria of an aqueous solution of bromide-based ionic liquids – measurements, correlations and application to absorption cycles

Abstract

In this work, thermodynamic and physicochemical properties including (vapor + liquid) equilibria (VLE), density and dynamic viscosity of binary mixtures composed of bromide-based ionic liquid (IL) and water were measured as a function of IL mole fraction in a wide range of temperature. The aqueous solution of the following ILs: 1-ethyl-1-methylpiperidinium bromide, ethylpyridinium bromide, 1-(2-hydroxyethyl)pyridinium bromide, 1-ethyl-1-methyl-morpholinium bromide, 1-hydroxyethyl-1-methylmorpholinium bromide, and N-ethyl-N,N-dimethyl-N-hydroxyethylammonium bromide have been tested for potential applications as working fluids in absorption refrigeration technology. The isothermal VLE has been measured by an ebulliometric method within a temperature range from T = (338.15–368.15) K and pressure up to 85 kPa and correlated using Redlich-Kwong equation of state. This work is a continuation of our systematic investigation of an aqueous solution of ionic liquids as a potential working fluid in absorption refrigeration technology. The summary of this research is the modeling of the theoretical cycles using working fluids proposed in this paper. The calculated values of the coefficient of performance (COP) were compared to other ILs from available literature and {LiBr + water} system, conventionally used on the industrial scale in absorption refrigeration technology.