Vapor pressures of propyl acetate, 1-butanol and 2-butanol and the isobaric (vapor+liquid) equilibrium of n-propyl acetate with 1-butanol at 0.1, 0.15 and 0.6 MPa as well as n-propyl acetate with 2-butanol at 0.15 and 0.6 MPa was investigated using a dynamic stainless steel ebulliometer. The experimental data for the binary systems were tested and verified to be thermodynamically consistent by the point-to-point test of Van Ness. Different thermodynamic-mathematical equations together with several activity coefficient models were used to correlate the experimental data. The average absolute deviations for the vapor phase compositions are all below 0.01. In addition, the ASOG and three versions of UNIFAC group contribution models were used to estimate the (vapor+liquid) equilibrium data. The UNIFAC-Dortmund globally generated the best predictions. The mean error in the activity coefficient was less than 7%. For the n-propyl acetate (1) + 1-butanol (2) system an azeotrope has been verified at 0.15 MPa (x(1azexp) =Y-1azexp = 0.949 and T-azexp = 387.61 K) and at 0.6 MPa (X-1azexp = Y-1azexp = 0.783 and T-azexp = 445.68 K) while for the n-propyl acetate (1) + 2-butanol (2) system, the azeotrope at 0.15 MPa was found at x(1azexp) =y(1azexp) = 0331 and T-azexp = 383.03 K and was not detected at 0.6 MPa. (C) 2014 Elsevier B.V. All rights reserved.