Measurement, correlation of solubility and thermodynamic properties analysis of 5,5′-bis(2,4,6-trinitrophenyl)-2,2′-bis(1,3,4-oxadiazole) in different mono solvents

In this paper, the solubility of 5,5'-bis(2,4,6-trinitrophenyl)-2,2'-bis(1,3,4-oxadiazole) (TKX-55) in methanol, ethanol, 1-propanol, 2-propanol, formic acid, acetic acid, propionic acid, acetonitrile, ethyl acetate, tetrahydrofuran, nitromethane, 1,2-dichloroethane, benzene and 1,4-dioxane was determined at T = (293.15-333.15) K under atmospheric pressure (P = 0.1 MPa) by a gravimetric method. The results showed that the solubility increases with rise of temperature in all selected solvents. Additionally, the solvent effect on TKX-55 solubility was investigated with Kamlet-Taft parameters. Moreover, Hansen solubility parameter was used for explaining the solubility order of TKX-55 in selected solvents, the consequences showed that solubility order of TKX-55 resulted from the comprehensive function of several solubility parameters. The solubility parameter of Delta delta(t) between TKX-55 and solvents reached from 0.17 MPa0.5 to 8.68 MPa0.5. The interaction energy (E-inter) between TKX-55 and selected solvents was calculated by molecular simulation to explain the solubility behavior. Activity coefficient was to access the solute-solvent molecular interactions. Besides, the solubility values were correlated by the modified Apelblat equation, lambda h equation, the polynomial empirical equation, and ideal equation, and the results showed that all models can give a satisfactory correlation. The average root-mean-square deviation (10(6)RMSD) values were 14.57, 33.08, 8.523 and 30.29, respectively. On the basis of the van't Hoff and Gibbs equations, the thermodynamic properties exhibited by TKX-55 (i.e., standard dissolution enthalpy (Delta H-dis(o)), standard dissolution entropy (Delta S-dis(o)) and standard dissolution Gibbs free energy (Delta(dis)G(o))) in the selected solvents were characterized and then discussed from the experiment data. As revealed from the result, TKX-55 in solvents selected showed a non-spontaneous process. The excess enthalpy of solution was estimated on the basis of lambda h equation. And solid-liquid surface tension (gamma) and surface entropy factor (f) of TKX-55 were estimated by using the experimental solubility data. Furthermore, the experimental solubility values, model parameters, and thermodynamic properties of TKX-55 in different pure solvents will provide the necessary support for its preparation, crystallization process, and further theoretical studies. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

The solubility of TKX-55 in various solvents was determined experimentally, and the influence of solvents on its solubility was investigated. The solubility order was explained by multiple solubility parameters. Molecular simulation was used to calculate the interaction energy and understand the solubility behavior. Thermodynamic properties and solvent-solute interactions were analyzed, and correlation models were established for solubility prediction.