Isothermal vapor-liquid equilibrium of the six binary systems 2-propanone + n-butane, + 2-methylpropane, + 1-butene, + cis-2-butene, + 2-methylpropene, + trans-2-butene were measured from (364.1 to 365.46) K with an automated static total pressure apparatus. Measured pTz data was reduced into pTxy data using the Barker method. Error analysis was conducted for all measured and calculated data. All measured systems exhibited positive deviation from Raoult's law, and an azeotropic point was found for the n-butane + 2-propanone system. Parameters of Wilson and UNIQUAC activity coefficient models were regressed with the experimental VLE data. Results obtained with two predictive methods, UNIFAC and COSMO-RS, were compared with measured data.