Solubility Measurement, Thermodynamic Correlation, and Comprehensive Analysis of 3,5-Dinitrobenzoic Acid in 13 Pure Solvents

Abstract

The solubility of 3,5-dinitrobenzoic acid in 13 solvents (methanol, ethanol, n-propanol, i-propanol, n-butanol, 2-butanol, i-butanol, n-pentanol, methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, and acetonitrile) was tested by gravimetry from 283.15 to 323.15 K under atmospheric pressure. The results showed that the solubility of 3,5-dinitrobenzoic acid increased with the increasing temperature in all pure solvents. Besides, the experimental solubility results of 3,5-dinitrobenzoic acid was fitted with thermodynamic equations like modified Apelblat equation, van’t Hoff equation, λh equation and the nonrandom two liquid equation. The results of average relative deviation, root-mean-square deviation, and coefficient of determination showed that the modified Apelblat equation correlates best of all models. Moreover, solvent effects and density functional theory (DFT) were introduced to demonstrate the dissolution properties of 3,5-dinitrobenzoic acid in the above solvents. At last, the dissolution process of 3,5-dinitrobenzoic acid in selected solvents was spontaneous according to the results of the mixing Gibbs free energy change (ΔmixG).