A Ghanadzadeh Gilani - Department of Chemistry, Faculty of science, University of Guilan, Rasht, Iran
H Ghanadzadeh Gilani - Department of Chemical Engineering, University of Guilan, Rasht, Iran
S Shekarsaraee - Department of Chemistry, Faculty of science, University of Guilan, Rasht, Iran
S.L. Seyed Saadat - Department of Chemistry, Faculty of science, University of Guilan, Rasht, Iran

Liquid–liquid equilibrium (LLE) data are investigated for mixtures of (water + phosphoric acid + amyl alcohol) at 298.15K and atmospheric pressure. The solubility curves and the tie-line end compositions of liquid phases at equilibrium were determined. The result show that this ternary mixture is type one liquid-liquid equilibrium system. The distribution coefficients and the selectivity factors for the immiscibility region are calculated. The reliability of the experimental tie-lines was confirmed by using Hand correlation. By modeling the above system, binary interaction parameters of the NRTL thermodynamic model was estimated. The NRTL model correlates the LLE data for T=298.15K with a root mean square deviation of 3.46 %, between the observed and calculated mole concentrations. It is concluded that amyl alcohol may serve as an adequate solvent to extract phosphoric acid from its dilute aqueous solution

Liquid–Liquid equilibria; Pentanol; Phosphoric acid; NRTL model