Document Type : Regular Article
Department of Chemistry, Faculty of Science, University of Guilan, Rasht, Iran
Departent of chemistry, University of Guilan. Rasht, Iran
Department of Chemistry, University of Guilan, Campus 2, Rasht, Iran
Solubility data and tie-line points were experimentally determined for the ternary system (water + phosphoric acid + Heptyl acetate) at T = 298.2 K and ambient pressure. The cloud point method was used to measure the immiscibility region. Type-1 LLE behavior was observed for the investigated system and the plait point data were calculated using the Treybal’s method. The compositions of both aqueous and esteric layers were determined by using of acid-base titration, HPLC method and mass balance equation. The Othmer–Tobias and Hand equations were applied to prove the reliability of tie-line data. Obtained tie-line points were then correlated using the UNIQUAC model and the rmsd results showed that the measured points were satisfactorily regressed by the thermodynamic model. To evaluate the ability of the studied solvent for purification of phosphoric acid, distribution coefficients and separation factors were calculated over the biphasic area. Separation factors were greater than one in all investigated feeds of phosphoric acid for the studied system. Heptyl acetate showed the highest separation factors between all the investigated n-alkyl acetate esters.