Vapor-liquid equilibrium (VLE) data for toluene + acrylic acid, toluene + acetic acid, and cyclohexane + acrylic acid systems have been determined at 20 kPa (absolute pressure) using a circulating VLE still. The Hayden and O'Connell equation has been used to account for the nonideality of the vapor phase. The experimental data were checked both with the Herington consistency test and point consistency test methods, which showed thermodynamic consistency. Only the toluene and acetic acid system presents an azeotrope at 20 kPa and 332.29 K with the mole fraction of toluene as 0.525. All equilibrium data were correlated with Wilson, nonrandom two-liquid (NRTL), and universal quasichemical (UNIQUAC) activity coefficient models to obtain the binary interaction parameters of these models using Aspen Plus commercial software to introduce them in the simulation model.