Solubility of 2-Nitro-4-methylsulfonyltoluene in 12 Monosolvents: Solvent Effect Analysis, Molecular Simulation, and Model Correlation

This study employed the static gravimetric method to determine the solubility of 2-nitro-4-methylsulfonyltoluene in 12 pure solvents at 283.15–323.15 K and 101.2 kPa. Unlike existing solubility studies that merely provide data, this work combines powder X-ray diffraction (PXRD), molecular electrostatic potential surfaces (MEPs), and interaction region indicator (IRI) analysis to reveal solubility mechanisms, which are its novelty. Solubility increased with temperature and followed the order: acetonitrile > acetone > methyl acetate > ethyl acetate > methanol > n-propanol > ethanol > n-butanol > isopropanol > n-pentanol > isobutanol > water at 298.15 K. PXRD confirmed no polymorph transition during dissolution. The modified Apelblat, NRTL, UNIQUAC, and Margules models were used for fitting, with the modified Apelblat model showing the best performance. MEPs and IRI spectra clarified weak solute–solvent interactions. This work offers not only essential solubility data but also mechanistic insights, providing reliable guidance for optimizing the crystallization and production processes of this compound.