Thermodynamic study of dilute aqueous solutions of organic compounds. Part 5.—Open-chain saturated bifunctional compounds

Abstract

Values have been determined at 25°C of the changes in the free energy, enthalpy and entropy corresponding to the process of transfer from the ideal gas state to dilute aqueous solution for ethylene-diamine, 2-methoxyethylamine, 3-methoxypropylamine, 1,2-dimethoxymethane and four 2-alkoxy-ethanols (methoxy to n-butoxy).

These data have been used to calculate the variations in the thermodynamic functions of hydration for the hypothetical process of introducing a Y group (Y = O, NH) into a monofunctional RX compound (X = O, NH, NH₂, OH), either by breaking a C—C or a C—H bond. Evidence of strong interactions between hydrophilic centres in bifunctional compounds emerges. The strength and nature (entropic or enthalpic) of these interactions depend on both the type of functional groups and their relative distance.