LIQUID-LIQUID PHASE EQUILIBRIA OF (1-PROPANOL + WATER plus n-ALCOHOL) TERNARY SYSTEMS AT 294.15 K. I. 1-PROPANOL + WATER+1-BUTANOL OR 1-PENTANOL OR 1-HEXANOL

Liquid-liquid equilibrium (LLE) data for the ternary systems: (1-propanol + water + 1-butanol), (1-propanol + water + 1-pentanol), (1-propanol + water + 1-hexanol) at 294.15 K and atmospheric pressure are reported. The studied n-alcohols are possible extraction solvents for the separation of 1-propanol from aqueous solutions. The phase equilibrium diagrams for all studied systems: miscibility curves, tie-lines and plait points are presented. The ternary systems exhibit the type-1 behaviour of LLE. The Othmer-Tobias and Hand equations used to verify the quality of the experimental data, gave similar results. The experimental ternary liquid-liquid equilibrium data were correlated with the UNIQUAC model. The correlation of the liquid-liquid equilibrium data evidenced that the UNIQUAC model represents well the experimental data and gives the original UNIQUAC parameters for the ternary systems. The values of distribution coefficients (D(i)), separation factors (S) and selectivity for solvent separation efficiency, derived from the tie-line data, were used to decide if these n-alcohols can serve as potential solvents for the separation of 1-propanol from aqueous solutions. A comparison of the extracting capabilities of the solvents with respect to distribution coefficients, separation factors, and solvent-free selectivity bases was made.