Effect of third component on separation behavior of water plus t-butanol+Na2SO3/Na2SO4 system at 298 +/- 2 K

The liquid-liquid and liquid-liquid-solid equilibria for the ternary t-butanol-water-Na2SO3/Na2SO4 system is reported at ambient pressure and at 298 +/- 2 K. The solubility data of solutions of Na2SO3/Na2SO4 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 SO32- and SO42- ions to cause phase separation have been explained. The salting-out ability of Na2SO3 is higher than that of Na2SO4 since the Gibbs free energy of hydration (Delta G(hyd)) of SO42-(-1080 kJ mol(-1)) is lower than that of SO32- (-1295 kJ mol(-1)) ion.