A Ghanadzadeh Gilani - Department of chemistry, University of Guilan , 41335 Rasht ,Iran
S.L Seyed Saadat - Department of chemistry, University of Guilan , 41335 Rasht ,Iran
O Rajabi - Department of chemistry, University of Guilan , 41335 Rasht ,Iran

Experimental solubility and tie-line data for the ternary system of (water + propionic acid +2-methyl-1-butanol) were measured at T = 308.2 K. Data for binodal curves were determinedby cloud-point titration method [1]. The concentration of each phase was determined byacidimetric titration, the Karl-Fischer technique, and refractive index measurements. A type-1LLE phase diagram was obtained for this ternary system. The experimental tie-line data werecorrelated using the UNIQUAC and NRTL models [2,3]. The reliability of the experimentaldata was determined through the Othmer–Tobias and Hand plots. Distribution coefficientsand separation factors were evaluated over the immiscibility regions [4].