In this work, Liquid-liquid equilibrium (LLE) data for ternary system, (water + propionic acid + 2-methoxy-2-methylpropane) and (water + butyric acid + 2-methoxy-2-methylpropane), were experimentally measured at atmospheric pressure and temperatures of 298.2 K and 323.2 K. The reliability of the experimental tie-line data was verified by the Othmer-Tobias and Hand equations. Distribution coefficients and separation factor values were evaluated for the immiscibility region. The consistency of experimental tie-line data was confirmed by the NRTL and UNIQUAC models. Both models describe the phase behavior of the studied systems accurately with very small average deviations. (C) 2015 Elsevier B.V. All rights reserved.