Determination and correlation solubility of m-phenylenediamine in (methanol,ethanol, acetonitrile and water) and their binary solvents from 278.15 K to 313.15 K

In this study, the solubility of m-phenylenediamine in four pure solvents (methanol, ethanol, acetonitrile and water) and three binary solvent (methanol + water), (ethanol + water) and (acetonitrile + water) systems were determined in the temperature ranging from 278.15 K to 313.15 K by using the gravimetric method under atmospheric pressure. In the temperature range of 278.15 K to 313.15 K, the mole fraction solubility values of m-phenylenediamine in water, methanol, ethanol, and acetonitrile are 0.0093-0.1533, 0.1668-0.5589, 0.1072-0.5356, and 0.1717-0.6438, respectively. At constant temperature and solvent composition, the mole fraction solubility of o-phenylenediamine in four pure solvents was increased as the following order:water < ethanol < methanol < acetonitrile; and in the three binary solvent mixtures could be ranked as follows:(ethanol + water) < (methanol + water) < (acetonitrile + water). The relationship between the experimental temperature and the solubility of m-phenylenediamine was revealed as follows:the solubility of mphenylenediamine in pure and binary solvents could be increased with the increase of temperature. The experimental values were correlated with the Jouyban-Acree model, van't Hoff-Jouyban-Acree model, modified Apelblat-Jouyban-Acree model, Sun model and Ma model. The standard dissolution enthalpy, standard dissolution entropy and the Gibbs energy were calculated based on the experimental solubility data. In the binary solvent mixtures, the dissolution of m-phenylenediamine could be an endothermic process. The solubility data, correlation equations and thermodynamic property obtained from this study would be invoked as basic data and models regarding the purification and crystallization process of m-phenylenediamine.