Experimental and correlational study of phase equilibria in aqueous solutions of phosphoric acid with alcohols at different temperatures

Liquid-liquid equilibrium (LLE) data were measured for the aqueous mixtures of phosphoric acid with 1-pentanol and 1-heptanol at T = (298.2, 308.2, and 318.2) K and atmospheric pressure. These ternary systems exhibit as Treybal's type-1 liquid-liquid phase behavior. The reliability of the experimental tie-lines was checked using the Othmer-Tobias and Hand correlation equations. The activity coefficient models of NRTL and UNIQUAC were applied to fit the experimental tie lines. For these models, values of the binary interaction parameters between each pair of components in the studied systems were obtained. Experimental distribution coefficients and selectivity factors for the immiscibility regions were determined.