Solubility and tie line data for the aqueous solutions of butyric acid with 1-octanol and 2-ethyl-1-hexanol at various temperatures

• Equilibrium data of (water + BA + 1-octanol or 2-ethyl-1-hexanol) were measured.
• Experimental LLE data were correlated with NRTL and UNIQUAC models.
• Distribution coefficients and separation factors were evaluated.

This study demonstrates the experimental and correlated tie line data for the aqueous solutions of butyric acid with two octanol isomers (C18H18O) at T = (298.2, 308.2, and 318.2) K and p = 101.3 ± 0.4 kPa, for the first time. The chosen isomers were 1-octanol and 2-ethyl-1-hexanol. The obvious difference between these two isomers is that the first isomer is a straight and later is a branched primary alcohol. Experimental solubility data were obtained using the cloud point method. The tie line data were determined by acidimetric titration, the Karl–Fischer technique, and refractive index measurements. Both the ternary systems exhibit type-1 behavior of LLE. The tie-line data were correlated using the UNIQUAC and NRTL models. For each system, the Othmer–Tobias and Hand correlations equations were used to establish the quality of the tie-line data. Distribution coefficients and separation factors were calculated over the biphasic area.

Solubility diagram for [water + BA + 1-octanol (○) or 2-ethyl-1-hexanol (□)] at T = 298.2 K.Figure optionsDownload as PowerPoint slide