Determination and correlation of solubility of an explosive in different pure solvents

Abstract

Information regarding relevant solid–liquid balance pertaining to 3-nitro-1H-pyrazole (3-NP) within a range of solvents is of a high significance to the preliminary analysis of industry-related uses. Here, through the gravimetric approach, 3-NP dissolvability in various clean solvents, i.e., n-butyl acetate (NBAC), isopropyl acetate (IPAC), n-propyl acetate (NPAC), ethyl acetate (EAC), methyl acetate (MAC), n-propanol (Pro-OH), ethanol (EtOH), methanol (MeOH), toluene (PhMe), acetonitrile (AN), tetrahydrofuran (THF), acetone (DMK), water and benzene (Ph), was explored under an atmosphere pressure of 0.1 MPa and within a range of temperature (T = 283.15 K to 323.15 K). In accordance with the outcomes, with the rise of the temperature, 3-NP dissolvability increased in fourteen solvents taken. Among all the solvents, water exhibiting the maximum polarity had the minimum dissolvability, while methanol exhibited the maximum quality of solubility. At a particular temperature, 3-NP’s quality of solubility followed that of MeOH (8.54 × 10-2, 323.15 K) > EtOH (6.46 × 10-2, 323.15 K) > Pro-OH (6.27 × 10-2, 323.15 K) > AN (4.18 × 10-2, 323.15 K) > DMK (3.76 × 10-2, 323.15 K) > MAC (3.20 × 10-2, 323.15 K) > EAC (2.82 × 10-2, 323.15 K) > NPAC (2.25 × 10-2, 323.15 K) > NBAC (1.91 × 10-2, 323.15 K) > IPAC (1.25 × 10-2, 323.15 K) > THF (1.07 × 10-2, 323.15 K) > PhMe (7.29 × 10-3, 323.15 K) > Ph (3.23 × 10-3, 323.15 K) > water (2.16 × 10-3, 323.15 K). The experimental data of 3-NP had a correlation according to Wilson approach, NRTL model, λh equation and the modified Apelblat equation. As was revealed from the fitting outcomes, the optimal correlative result of the experimental information was given through NRTL model. The relative average deviation (102ARD) and the root-mean-square deviation (104RMSD) achieved were lower than 9.44 and 23.75 separately. Moreover, 3-NP dissolvability characteristics in solvents studied were analyzed with the use of the Hansen dissolvability coefficient (δd, δp, δh, δt, and Δδt) here. This study determined the effect exerted by interacting processes pertaining to solvent–solute and solvent–solvent molecules upon the 3-NP’s quality of solubility with the association of linear solving energy in accordance with the descriptors of the solvents. Moreover, the mixing characteristics of 3-NP in 14 pure solvents, including the mixing Gibbs energy (ΔmixG), mixing enthalpy (ΔmixH) and mixing entropy (ΔmixS), were determined and analyzed through Wilson approach. The result of ΔmixG < 0 indicated that the dissolution pertaining to 3-NP in the solvents taken was spontaneous. The data pertaining to lnγ1∞ and lnγ1 was similar, demonstrating that 3-NP in the solution mechanisms of solvents taken was not highly non-ideal. The results presented conducive data in terms of actual 3-NP crystallization optimizing procedure.