Studies on Vapor–Liquid Equilibrium of Binary Systems Containing the MMA Component under Normal Atmospheric Pressure

Methyl methacrylate (MMA) is an important monomer for plexiglass synthesis. In order to obtain high-purity MMA, the vapor–liquid equilibrium data of the system containing MMA are very important for subsequent separation. In this paper, the vapor–liquid equilibrium data of four selected binary systems, that is, methanol (1)–MMA (4), methyl propionate (2)–MMA (4), methyl propionate (2)–methyl iso-butyrate (3), and methyl iso-butyrate (3)–MMA (4), were investigated by an Ellis distillatory under 1 atmospheric pressure. The experimental data were all checked by the Herington area method, and they passed the thermodynamic consistency test, as confirmed by the statistical method. Then, these data were well correlated by the Wilson, NRTL, and UNIQUAC activity coefficient models integrated in Aspen Plus software. The regressed parameters of the activity coefficient models were obtained. The mean absolute deviations (MADs) of the vapor phase composition y 1 and equilibrium temperature t for the methanol (1)–MMA (4) binary system by the three activity coefficient models under atmospheric pressure were found to be 0.005, 0.55 °C; 0.007, 0.62 °C; and 0.005, 0.55 °C, respectively. For the other three binary systems, very similar results were obtained. An azeotropic point exists in the methanol (1)–MMA (4) binary system at a temperature of 64.60 °C and composition x 1 = 0.96 under atmospheric pressure. Further, the azeotropic point for the iso-butyrate (3)–MMA (4) binary system exists at 92.39 °C and x 3 = 0.925 under 1 atmospheric pressure.