Solubility measurement, correlation, and thermodynamic analysis of ε-CL-20 in four binary solvents (ethyl acetate + halogenated hydrocarbon) from 288.15 to 328.15 K

In this work, the solubility of ε-CL-20 in four binary solvents composed of ethyl acetate and halogenated hydrocarbons (bromobenzene, chlorobenzene, dibromomethane, 1,1,2,2-tetrachloroethane) was measured over the temperature range of 288.15–328.15 K at 0.101 MPa by gravimetric method. Under similar conditions, the order of solubility of ε-CL-20 is ethyl acetate + bromobenzene ≈ ethyl acetate + chlorobenzene > ethyl acetate + dibromomethane > ethyl acetate + 1,1,2,2-tetrachloroethane and the solubility decreases with the increase of halogenated hydrocarbon content. The results also reveal that the solubility is negatively correlated with temperature when the mole fraction of halogenated hydrocarbons is low, otherwise the result is opposite. The modified Apelblat model, van’t Hoff model, CNIBS/R-K model, Jouyban-Acree model and Jouyban-Acree-van’t Hoff model were used to correlate the experimental solubility data and all of the models perform well. The modified Apelblat model and Jouyban-Acree-van’t Hoff model are relatively excellent. The dissolution thermodynamic properties of ε-CL-20 in four binary solvents were calculated and analyzed. The results show that the dissolution processes of ε-CL-20 are entropy-driven non-spontaneous processes. This work is significant to the design and optimization of the crystallization of ε-CL-20.