Thermodynamic study of aqueous two phase systems for some aliphatic alcohols + sodium thiosulfate + water

The aqueous two phase systems for 1-propanol, 2-propanol, 2-methyl-2-propanol, 2-butanol or ethanol + sodium thiosulfate + water ternary systems at T = 298.15 K were studied thermodynamically, and an empirical three parameter equation was successfully used for the correlation of binodal data. The phase-separation ability of the studied systems was discussed on the basis of the solubility and boiling point of the constitutive alcohol. Furthermore, the effect of temperature on the phase-separation ability of the studied systems was discussed in terms of the experimental cloud-point data as a function of alcohol mole fraction at the temperature ranges of T = (293.15–323.15) K at 5 K intervals. Additionally, the segment based Wilson equation was generalized to represent the mixed organic–aqueous solvent electrolyte systems and successfully used for the correlation of binary and ternary data, and the restricted binary interaction parameters were also reported. The result of the correlation using generalized Wilson model was also compared with the e-NRTL model.

► LLE of some aliphatic alcohols + sodium thiosulfate + water was studied.
► Phase-separation ability of different alcohols was discussed.
► An empirical three parameter equation was used for the correlation of binodals.
► Segment based Wilson model was used to represent the LLE data.