Determination and correlation of solubility of N-methyl-3,4,5-trinitropyrazole (MTNP) in ten pure solvents from 283.15 K to 323.15 K

Abstract The solubility of N-methyl-3,4,5-trinitropyrazole (MTNP) in ten pure solvents, including benzene, methanol, ethanol, n-propanol, isopropyl alcohol, n-butanol, isobutyl alcohol, n-pentanol, isoamyl alcohol and water, were firstly determined by the gravimetric method with the temperature ranging from 283.15 K to 323.15 K under atmospheric pressure (0.1 MPa). The results indicated that the solubility of MTNP increases with the increasing temperature in each pure solvent. Furthermore, the solubility of MTNP in alcohols decreases as the increasing number of carbon atoms and methanol has more dissolving capacity. Additionally, to extend the applicability of the solubility, the modified Apelblat equation, λh equation, the ideal model and the polynomial empirical equation were used to correlate the solubility values. Besides, standard dissolution enthalpy Δ dis H o , standard dissolution entropy Δ dis S o and standard dissolution Gibbs free energy Δ d i s G o of dissolution were calculated and discussed from the experimental data. Moreover, the solubility of MTNP in each pure solvent will provide essential support for crystallization and further theoretical studies.