A static total pressure apparatus was built to measure isothermal vapour-liquid equilibrium (VLE) of six binary systems of n-butane + 2-propanone at 330.2 K, 2-methyl-propane + 2-propanone at 318.6 K, 1-butene + 2-propanone at 323.3 K. cis-2-butene = 2-propanone at 331.9 K, 2-methyl-propene + 2-propanone at 323.1 K, and trans-2-butene + 2-propanone at 332.1 K. Total pressure measurements were performed to obtain pTz data. The measurements are treated using the Barker's method to provide pTxy. VLE data have been correlated by Wilson, UNIQUAC, and NRTL activity coefficient models as well as using Legendre polynomials. (C) 2004 Elsevier B.V All rights reserved.