Thermodynamic investigation of the ATPSs composed of some (aliphatic alcohol + sodium carbonate + water) ternary systems

In this work, the (liquid + liquid) equilibrium of 1-propanol, 2-propanol, 2-methyl-2-propanol, 2-butanol, or (ethanol + sodium carbonate + water) ternary systems was studied. Binodal curves and tie-line data at T = 298.15 K were reported. The effect of temperature was studied using the obtained cloud-point data as a function of alcohol mole fraction at temperature range T = (293.15 to 328.15) K with 5 K intervals. The free energy, enthalpy, and entropy of clouding point (CP) estimated using a simple method, and the driving force of the two-phase formation process was discussed on the base of the estimated free energy values. Salting-out effect was discussed using the values of parameters of one parameter effective excluded volume (EEV) model. The effect of different alcohols on the phase-separation ability of the studied systems was discussed on the base of the intermolecular interactions. Also, a new three parameter nonlinear equation developed and successfully used for the correlation of the binodal curves, and the correlation coefficients were also reported. Moreover, the generalized electrolyte-NRTL model to the mixed solvent electrolyte systems (e-NRTL) was satisfactorily used for the correlation of the tie-line compositions, and the binary interaction parameters were also reported.

► LLE of some (aliphatic alcohols + sodium carbonate + water) was studied. ► Free energy, enthalpy, and entropy of clouding-point was estimated. ► Scaled effective excluded volume (EEV) values were obtained. ► Phase-separation ability of different the alcohols and salts was discussed. ► e-NRTL was satisfactorily used for the correlation of the tie-line compositions.