Liquid–liquid equilibrium of aqueous two-phase systems composed of hydrophilic alcohols (ethanol/2-propanol/1-propanol) and MgSO4/ZnSO4 at (303.15 and 313.15) K and correlation

Binodal data for ethanol, 2-propanol and 1-propanol + magnesium sulfate/zinc sulfate + water systems were experimentally determined at (303.15 and 313.15) K, respectively. An empirical equation was used to correlate binodal data. The liquid–liquid equilibrium data for part of the investigated systems were obtained via the MATLAB. In order to evaluate the dependability of the calculation method and the tie-line data, the liquid–liquid equilibrium data were correlated by the Othmer–Tobias and Bancroft equations. The salting-out abilities of the investigated salts and the phase-forming abilities of the investigated hydrophilic alcohols were discussed by the effective excluded volume (EEV) of salt. The salting-out abilities of the investigated salts follow the order ZnSO4 > MgSO4, which can be indicated by the location of the binodal curves plotted in molality and the salting-out coefficient. In addition, the phase-forming abilities of the investigated hydrophilic alcohols follow the order: 1-propanol > 2-propanol > ethanol.

► The phase diagrams of hydrophilic alcohols–salts ATPSs were determined.
► The LLE data were obtained by calculated method.
► The experiential equations were used to correlate the binodal data and LLE data.
► The salt-outing abilities of the salts have been discussed.
► The phase-forming abilities of the hydrophilic alcohols have been discussed.