Solubilities of 2,6-Diamino-3,5-dinitropyrazine-1-oxide in the Binary Mixtures of DMSO+H₂O, DMF+H₂O and NMP+H₂O in the Temperature Range from 293.15 to 323.15 K under the Atmospheric Pressure

Recrystallization is usually required for the application of 2,6-Diamino-3,5-dinitropyrazine-1-oxide (LLM-105) as an energy material due to its poor crystal morphology. The study of its solubilities in binary solvent mixtures can provide primary support for optimizing the recrystallization and spheroidization conditions of LLM-105. In the current work, the solubilities of LLM-105 in the binary mixtures of dimethyl sulfoxide (DMSO)+H₂O, N,N-dimethyl-formamide (DMF)+H₂O and 1-methyl-2-pyrrolidone (NMP) +H₂O were measured by the gravimetric method in the temperature range from 293.15 K to 323.15 K under the atmospheric pressure. The results suggest that the solubility of LLM-105 increases with the increase of temperature and the concentration of the solvent. The experimental data were then fitted with the modified Apelbalt equation, (CNIBS)/Redlich-Kister equation and Jouyban-Acree equation. All models fit the experimental data well, indicating that they can be used to predict the solubilities of LLM-105 in the binary solvent mixtures. The thermodynamic parameters of the dissolution including enthalpy, standard entropy and Gibbs energy were calculated from the experimental data. It was found that the dissolutions of LLM-105 in all test solvents were endothermic.