Determination and correlation of solubility of 2,2′,4,4′,6,6′-hexanitro-1,1′-biphenyl and 2,2′,2″,4,4′,4″,6,6′,6″-Nonanitro-1,1′:3′,1″-terphenyl in six pure solvents

Abstract

The knowledge of solubility and dissolution thermodynamics for 2,2′,4,4′,6,6′-hexanitro-1,1′-biphenyl (HNBP) and 2,2′,2″,4,4′,4″,6,6′,6″-Nonanitro-1,1’:3′,1″-terphenyl (NONA) in different solvents is not only significant for its crystallization and further theoretical studies, but also important to the use of HNBP and NONA in the related fields. In this paper, the gravimetric method was used to determine the solubility of HNBP and NONA in benzene, toluene, xylene, chlorobenzene, anisole and epichlorohydrin at temperatures ranging from (313.15–353.15) K under atmospheric pressure. The experimental results show that the solubility of HNBP and NONA monotonously increase with the temperature increasing in all selected solvents. Meanwhile, under the same conditions the solubility and solubility changes with temprature of HNBP are greater than that of NONA. To fit and extend the application range of the experimental solubility data, the modified Apelblat equation, λh equation, polynomial empirical equation and ideal van't Hoff model were used to correlate the experimental values of HNBP and the modified Apelblat equation, polynomial empirical equation and ideal van't Hoff model were used to correlate the experimental values of NONA. It was found that the correlated results of selected correlation equations are all in good agreement with the experimental values. And the polynomial empirical equation provided better correlation results than the other models. Furthermore, the standard dissolution enthalpy, standard dissolution entropy and Gibbs energy were calculated from the experimental molar fraction solubility data. The calculated thermodynamic parameters indicated that the dissolution of HNBP and NONA in the selected solvents is a favorable process and endothermic process.