Isobaric vapor-liquid equilibrium (VLE) data were determined for the binary systems sec-butyl alcohol + N,N-dimethyl formamide (DMF), sec-butyl acetate + DMF and the ternary system sec-butyl alcohol + sec-butyl acetate + DMF at 101.3 kPa using a vapor-liquid equilibrium still. The thermodynamic consistency of the experimental data was checked by Herington method and McDermott-Ellis method. The experimental VLE data were correlated with the Wilson, NRTL, and UNIQUAC activity coefficient models. The VLE data for binary and ternary systems were then predicted by the correlated binary interaction parameters. The results show that the calculated values of vapor phase mole fraction and boiling temperature by the Wilson, NRTL, and UNIQUAC models agree well with the experimental data. And the binary pseudo-azeotrope of sec-butyl alcohol and sec-butyl acetate was eliminated when the mass ratio of DMF to the binary mixture is 2:1. Thus, DMF is a promising solvent for separation of the binary pseudo-azeotrope of sec-butyl alcohol and sec-butyl acetate in extractive distillation. (C) 2014 Elsevier B.V. All rights reserved.