Phase diagrams for (water + 1,2-butanediol or propanediol + 2-ethyl-1-hexanol) systems

(Liquid + liquid) equilibrium (LLE) data (water + 1,2-butanediol + 2-ethyl-1-hexanol) and (water + propanediol + 2-ethyl-1-hexanol) were determined at T = 298.2 K and atmospheric pressure. Phase diagrams were obtained for these ternary systems. Distribution coefficients and separation factors were measured to evaluate the extracting capability of the solvent. The UNIQUAC model was used to correlate the observed LLE data with a root mean square deviation value of 1.75 and 0.74 for 1,2-butanediol and propanediol mixtures, respectively. The reliability of the experimental data was confirmed by using the Othmer–Tobias correlation.

► Tie line data were obtained for (water + 1,2-butanediol + 2-thethyl-1-hexanol) and (water + propanediol + 2-ethyl-1-hexanol) ternary systems at T = 298.2 K.
► Distribution coefficients and separation factors were measured for these ternary systems. It has been shown that 2-ethyl-1-hexanol has high separation factor for extraction of 1,2-butanediol from its aqueous solutions.
► Experimental LLE data were analyzed correlated using UNQUAC model.
► The average RMSD (the root-mean-square deviation) value between the observed and calculated mass percent were 1.75 and 0.74, respectively, for 1,2-butanediol and propanediol solutions.