Experimental and correlated liquid-liquid equilibrium data for water-phosphoric acid-ester

In this study, experimental liquid-liquid equilibria were studied for the {water + phosphoric acid + ester (n-propyl- and n-amyl acetates)} systems at T = (298.2, 308.2, and 318.2) K and p = 101.3 kPa. The studied systems exhibit type-1 binodal curves. Solubility curves data were measured by cloud-point titration method. Tie line measurements were carried out by acidimetric titration, the Karl-Fischer technique, and refractive index measurements. Correlation of the experimental equilibrium data was carried out using NRTL and UNIQUAC thermodynamic models. The quality of the tie-lines was checked through The Othmer-Tobias correlation equation. Distribution coefficients and separation factors were calculated over the biphasic regions. The experimental results indicate that n-amyl acetate is better solvent than n-propyl acetate for removal of phosphoric acid from water. (C) 2018 Elsevier Ltd.