Liquid–liquid equilibria for water + 1-propanol (or 1-butanol) + potassium chloride + ammonium chloride quaternary systems at 298.15 K

• Investigate phase behavior of water + 1-propanol (or 1-butanol) + KCl + NH4Cl systems at 298.15 K.
• Good agreement has been obtained with several equations and models.
• Phase-separation ability is 1-butanol > 1-propanol and salting-out ability is KCl > NH4Cl.
• Liquid–liquid regions increase with the increasing of KCl/NH4Cl mass-fraction ratio.

Liquid–liquid equilibria (LLE) for quaternary systems of (water + 1-propanol + KCl + NH4Cl) and (water + 1-butanol + KCl + NH4Cl) were investigated at 298.15 K. Variation of phase behavior was studied by two integrated phase diagrams, the solvation abilities of salts and the polarities of alcohols. Binodal curves were fitted by three-parameter equation at different salt (KCl and NH4Cl) mass-fraction rations (0/1, 1/3, 1/1, 3/1 and 1/0). Tie-lines data of four related ternary systems (salt mass-fraction ratios 0/1 and 1/0) were successfully described by Othmer–Tobias and Hand equations, while the tie-lines data and saturated equilibrium data of quaternary systems (salt mass-fraction ratios 1/3, 1/1, 3/1) were correlated using the modified Eisen–Joffe equation.