Enthalpies of β-Alanine Dissolution in Some Water plus Organic Mixtures at 298.15 K

The enthalpies of solution (Delta H-sol(m)) of beta-alanine in aqueous solutions of acetonitrile (AN), 1,4-dioxane (1,4-DO), acetone (AC), formamide (FA), N-methylformamide (MFA), N,N-dimethylformamide (DMFA), N,N-dimethylacetamide (DMA), and dimethyl sulfoxide (DMSO) have been determined by calorimetric method as a function of organic solvent concentration at 298.15 K. Enthalpies of transfer (Delta H-tr degrees) of beta-alanine from water to aqueous organic mixtures as well as the enthalpy coefficients of pairwise interaction (h(xy)) were calculated from these data. The interrelation between enthalpy characteristics of beta-alanine dissolution (transfer) and the composition of water organic solvent binary mixtures has been ascertained. By means of a modified Kamlet-Taft equation the contributions of different physicochemical properties of organic cosolvents to the energy of beta-alanine-cosolvent intermolecular interactions have been estimated quantitatively.