Liquid–liquid equilibria of aqueous systems containing alcohol and ammonium sulfate

Binodal data and liquid–liquid equilibrium (LLE) data for alcohol + ammonium sulfate + water systems were measured using the cloud-point method and saturation density method at different temperatures. The effect of temperature on the phase-forming ability of isopropanol and n-butanol was also discussed, based on the phase diagrams. Furthermore, an empirical nonlinear expression was used to reproduce the experimental binodal data. The liquid–liquid equilibrium compositions of the aqueous systems were correlated and predicted using Othmer–Tobias and Bancroft equations at different temperatures. The results obtained from the correlation were consistent with root mean square deviations that were always below 1.7% as mass fractions between the experimental and calculated compositions of both equilibrium phases.

► Binodal data and LLE data for the alcohol + ammonium sulfate + water systems are measured.
► The effect of temperature on the phase-forming ability of isopropanol and n-butanol are discussed.
► An expansion in the biphasic area occurs with an increment in temperature.
► Binodal curves are satisfactorily correlated by a nonlinear equation.
► The results of the correlation with Othmer–Tobias and Bancroft equations are satisfactory.