Effect of third component on separation behavior of water+ t -butanol+Na 2 SO 3 /Na 2 SO 4 system at 298±2 K

The liquid-liquid and liquid-liquid-solid equilibria for the ternary t -butanol-water-Na 2 SO 3 /Na 2 SO 4 system is reported at ambient pressure and at 298 ± 2 K. The solubility data of solutions of Na 2 SO 3 /Na 2 SO 4 in water, t- butanol and solutions of varying compositions of t- butanol in water are reported. The phase diagrams for the studied systems are developed and salting-out effect of salt anion has been described. The structural properties of aqueous t- butanol solutions and the salting-out effect of SO 3 2- and SO 4 2- ions to cause phase separation have been explained. The salting-out ability of Na 2 SO 3 is higher than that of Na 2 SO 4 since the Gibbs free energy of hydration (Δ G hyd ) of SO 4 2- (−1080 kJ mol -1 ) is lower than that of SO 3 2- (−1295 kJ mol -1 ) ion.