Solubility and thermodynamic properties of a kind of explosives in four binary solvents

The solubility values of 1-methyl-3,4,5-trinitropropyrazole (MTNP) in four different binary solvents of water + (methanol, ethanol, 1-propanol and 2-propanol) at nine different temperatures from (283.15 to 323.15) K were firstly measured by a gravimetric method under atmospheric pressure. The experimental data showed that the solubility of MTNP increases with the increasing temperature in binary solvent mixtures. Besides, the dissolving capacity of MTNP decreased with the increasing water mole fraction ranging from 0.1000 to 0.7000 at a temperature. Additionally, results of these measurements were correlated by the modified Apelblat equation, vant't Hoff equation, CNIBS/R-K model and Jouyban-Acree model, and all of the models provided a satisfactory results in binary solvents. In addition, the thermodynamic properties of solution in different binary solvent mixtures, such as enthalpy, Gibbs energy and entropy can be calculated by the vant't Hoff equation and the Gibbs equation. Apparent thermodynamic quantities of mixing were also calculated for MTNP using values of the ideal solubility reported in the literature. Solid-liquid surface tension and surface entropy factor of MTNP were estimated by using the experimental solubility data.