Studying thermodynamic aspects of sublimation, solubility and solvation processes and crystal structure analysis of some sulfonamides

Crystal structures of N-(2-chlorophenyl)-benzene-sulfonamide (I), N-(2,3-dichlorophenyl)-benzene-sulfonamide (II), N-(4-chlorophenyl)-benzene-sulfonamide (III) were solved by X-ray diffraction method. Temperature dependencies of saturated vapor pressure and thermodynamic functions of sublimation process were calculated (I: ΔGsub298=50.4 kJ mol−1; ΔHsub298=114±1 kJ mol−1; ΔSsub298=213±3 J mol−1 K−1; II: ΔGsub298=54.1 kJ mol−1; ΔHsub298=124.9±1.6 kJ mol−1; ΔSsub298=237±5 J mol−1 K−1; III: ΔGsub298=49.9 kJ mol−1; ΔHsub298=98.6±1.9 kJ mol−1; ΔSsub298=163±5 J mol−1 K−1). Thermochemical parameters of fusion process for the compounds were obtained. Enthalpies of evaporation were estimated from enthalpies of sublimation and fusion. Temperature dependencies of the solubility in water, n-octanol and n-hexane were measured. The thermodynamic functions of solubility and solvation processes were deduced. Specific and non-specific solvation terms were distinguished using the transfer from the “inert” n-hexane to the other solvents. The transfer processes of the molecules from water to n-octanol were analyzed and main driven forces were established.