Liquid-liquid equilibria of two ternary mixtures 2MIB-2MIBOH-H2O and 2M2B-2M1BOH-H2O were measured at 5, 15 and 25 degreesC. UNIQUAC and NRTL models were fitted to the experimental data using ASPEN PLUS. Both experimental and correlated values of equilibrium compositions were compared with the values predicted by UNIFAC method. The same procedure was extended to the quaternary mixture 2M1B-2M2B-2M1BOH-H2O. The regressed results were in good agreements with experimental data. "Original UNIFAC model" performed better representation than "Dortmund UNIFAC model".