Ternary liquid–liquid equilibrium data for the (water + butyric acid + n-hexane or n-hexanol) systems at T = (298.2, 308.2, and 318.2) K

In this study, liquid–liquid equilibrium (LLE) values for the (water + butyric acid + n-hexane) and (water + butyric acid + n-hexanol) ternary systems were experimentally obtained at T = (298.2, 308.2, and 318.2) K and atmospheric pressure for the first time. The cloud point method was used to determine the solubility data. The concentration of each phase was determined by acidimetric titration, the Karl-Fischer technique, and refractive index measurements. Both the ternary systems exhibit type-1 behaviour of LLE. The experimental tie-line data were correlated using the UNIQUAC and NRTL models. The Othmer–Tobias and the Hand correlation equations were used to check the consistency of the obtained tie-line data for each system. Distribution coefficients and separation factors were calculated over the immiscibility regions. Finally, the Katritzky LSER multi-parameter equation was used to correlate the separation factors.

Phase diagram for the {(water + BA + n-hexane (○) or n-hexanol (Δ)} at T = 298.2 K.Figure optionsDownload as PowerPoint slideHighlights
► Liquid phase equilibria of (water + BA + n-hexane or n-hexanol) were studied.
► Experimental LLE data were correlated with NRTL and UNIQUAC models.
► Distribution coefficients and separation factors were calculated.
► The Katritzky LSER equation was used to correlate the separation factors.