Solubility determination, thermodynamic analysis and molecular dynamics simulation of N-Ethyl-p-toluenesulfonamide in three binary solvents

Background : Elucidating the solubility behavior of N-Ethyl-p-toluenesulfonamide (N-PTSA) in binary solvent systems provides a crucial theoretical basis for designing industrial crystallization processes with high selectivity and yield. Methods : The solubility data of N-PTSA in three binary mixed solvents methanol + water, ethanol + water, and n-propanol + water were determined gravimetrically over a temperature range of 288.15-318.15 K. Combined analyses of surface electrostatics and radial distribution functions (RDF) were employed to identify the microscopic interactions between N-PTSA and the mixed solvents. Significant Findings: The solubility of N-PTSA is positively correlated with temperature and the molar fraction of alcohol solvent. The improved Apelblat model, Ma model, NRTL model and λh model were used to conduct correlation analysis on the solubility data. The average absolute relative deviation (ARD) of the four models was all less than 5%, and the fitting effect was good. The RDF and the mean square displacement (MSD) further confirm that both solute-solvent and solvent-solvent interactions have an impact on the dissolution behavior of N-PTSA.