Solid–liquid equilibrium of dimethyl terephthalate (DMT), dimethyl isophthalate (DMI) and dimethyl phthalate (DMP) in melt crystallization process

The binary solid–liquid equilibrium of Dimethyl Terephthalate (DMT), Dimethyl Isophthalate (DMI) and Dimethyl Phthalate (DMP) was investigated by experiment and differential scanning calorimetry (DSC). The result demonstrated DMT/DMI and DMT/DMP systems are eutectic while DMI/DMP is a solid-solution system. The eutectic temperature of DMT/DMI system is 336.7   K and that of DMT/DMP is 271.1   K. Furthermore, a classical solid–liquid phase equilibrium model was used to fit the experimental data of the eutectic systems of DMT/DMI and DMT/DMP and the theoretical model could describe the eutectic solid–liquid phase diagrams properly.