A thermodynamic study on the phase behaviour of ethanol and 2-propanol in aqueous ammonium sulphate/sodium sulphate solution.

Liquid–liquid equilibrium (LLE) data for quaternary systems containing ethanol + 2-propanol + salt [(NH 4 ) 2 SO 4 /Na 2 SO 4 ] + water were experimentally determined at 308.15, 318.15 and 328.15 K. Binodal curves were fitted to four empirical nonlinear equations, whereas tie-lines were fitted to the Setschenow-type equation and its temperature-dependent expression as well as another two-parameter equation. All of the models were successfully correlated with the experimental data. Factors affecting the phase-forming abilities of the investigated systems were also studied, such as the temperature, mass fraction of ethanol in the alcohol mixture and type of salt. The effective excluded volume values for the studied systems also were determined to evaluate the phase separation abilities of investigated systems. These data can be used for the development and design of extraction processes utilizing such systems. [ABSTRACT FROM AUTHOR]