Solubility determination and correlation for 3-nitropyrazole in four binary solvents (water plus methanol, ethanol, 1-propanol and acetone) from 283.15 K to 323.15 K

The solubility of 3-nitropyrazole in four binary solvents (water + methanol, ethanol, 1-propanol and acetone) was measured by a dynamic laser monitoring over the temperature range of 283.15 K, 288.15 K, 293.15 K, 298.15 K, 303.15 K, 308.15 K, 313.15 K, 318.15 K and 323.15 K at pressure of 0.1 MPa. The solubility of 3-nitropyrazole increased positively with increasing temperature, while increased with decreasing mass-fraction of water in each binary system. Moreover, the experimental solubility values of 3-nitropyrazole in this work were correlated well with four thermodynamic models namely "the modified Apelblat equation, lambda(h) equation, Jouyban-Acree model and CNIBS/R-K model" obtaining average relative deviations (10(4)RMSD) lower than 4.79 for correlative studies, which shows that all the four models have a good correlation. Through the comparison of R-2 and 10(4)RMSD, it was found that the modified Apelblat equation can get more satisfactory results. In addition, Hansen solubility parameters were used to explain and predict the solubility behavior. Solute-solvent interaction was calculated by molecular simulation to investigate the solubility behavior deeply. Finally, the thermodynamic parameters (Delta(dis)G(o), Delta H-dis(o), Delta S-dis (o)) of 3-nitropyrazole dissolution processes in investigated four binary solvents were evaluated utilizing the van't Hoff equation. The positive Delta H-dis(o) and Delta S-dis(o), indicate that the dissolution processes of 3-nitropyrazole are endothermic and entropy-driven in all chosen binary solvents. And the main contributor of DdisGo is positive enthalpy. The solubility of 3-nitropyrazole in mixed solvents (water + methanol, water + ethanol, water + 1-propanol and water + acetone) will provide essential support for the further researches of crystallization and spheroidization of 3-nitropyrazole. (C) 2021 Elsevier B.V. All rights reserved.