Enthalpy Characteristics of Solvation of 1-Aza-18-crown-6 in Water–Ethanol and Water–Dimethyl Sulfoxide Solvents

Abstract

The thermal effects of dissolution of 1-aza-18-crown-6 in water–ethanol and water–dimethyl sulfoxide mixed solvents at 298.15 K were determined by calorimetry. In water and aqueous organic solvents with initial cosolvent additions, dissolution of 1-aza-18-crown-6 is exothermic. When the cosolvent content exceeds 0.2 mole fractions, the dissolution of 1-aza-18-crown-6 is accompanied by an endo effect, which increases with the contents of both ethanol and dimethyl sulfoxide. The enthalpies of transfer of 1-aza-18-crown-6 from water to aqueous ethanol and dimethyl sulfoxide solutions were calculated. The enthalpy characteristics of crown ether solvation in aqueous organic solvents were compared.