Solubility modeling and solvation behavior of 3,3′-diamino diphenylsulfone in binary aqueous mixtures of isopropanol, methanol, ethanol and N,N-dimethylformamide

Abstract

Experimentation of equilibrium solubility of 3,3′-diamino diphenylsulfone (DDS) in binary solvents of isopropanol/N,N-dimethylformamide (DMF)/methanol/ethanol + water was executed by means of the shake-flask technique under pressure of 101.2 kPa ranging from 283.15 to 328.15 K. At the experimental conditions of same temperature and same compositions of solvent species, the maximum solubility magnitude of DDS in mole fraction was found in the DMF + water solution system; and the minimum one, in the isopropanol + water solution system. Solubility correlation was made by employing four parametric expressions, e.g. modified Wilson, Jouyban–Acree, mixture response surface (MRS) and modified Jouyban–Acree–van’t Hoff, getting the root-mean-square and relative average deviations of no greater than 323.9 × 10−5 and 7.30 %, respectively. The extended Hildebrand solubility approach was practiced here to investigate the inter- and intra-molecule interactions of studied systems. In the regions of poor organic solvent composition, association behavior appears between DDS and solvent species in solutions. What's more, quantitative evaluation of the local compositions of DMF (methanol, isopropanol or ethanol) and water in the vicinity of DDS were carried out by employing the technique of Inverse Kirkwood–Buff integrals. In rich proportions of organic solvents for the studied solution systems, DDS was preferentially solvated by DMF (methanol, isopropanol or ethanol). DDS could mostly serve as a Lewis acid in front to the molecules of DMF (methanol, isopropanol or ethanol).