Solubility measurement and correlation of 4-nitrophthalimide in (methanol, ethanol, or acetone) plus N,N-dimethylformamide mixed solvents at temperatures from 273.15 K to 323.15 K

The solubility of 4-nitrophthalimide in binary (methanol + N,N-dimethylformamide (DMF), ethanol + DMF) and (acetone + DMF) solvent mixtures were investigated by the isothermal dissolution equilibrium method under atmosphere pressure. These studies were carried out at different mass fractions of methanol, ethanol or acetone ranging from 0.1 to 0.9 at temperature T = (273.15-323.15) K. For the nine groups of each solvent mixture studied, the solubility of 4-nitrophthalimide in mixed solutions increased with increasing temperature and mass fraction of methanol, ethanol or acetone for the three systems including (methanol + DMF), (ethanol + DMF) and (acetone + DMF). At the same temperature and mass fraction of methanol, ethanol or acetone, the mole fraction solubility of 4-nitrophthalimide in (acetone + DMF) was greater than that in the other two binary solvents. In addition, the experimental mole fraction solubility was correlated by four models (Jouyban-Acree model, van't Hoff-Jouyban-Acree model, modified Apelblat-Jouyban-Acree model and Sun model). The Jouyban-Acree model gave best representation for the experimental solubility values. Furthermore, the standard molar enthalpies of 4-nitrophthalimide during the dissolving process (DsolHo) were also obtained in this work, and the results show that the dissolution process is endothermic. The experimental solubility and the models used in this work will be helpful in separating 4-nitrophthalimide from its isomeric mixtures. (C) 2016 Elsevier Ltd.