Enthalpies of solution of β-alanyl-β-alanine in aqueous solution of amides at 298.15 K

The enthalpies of solution ΔsolHm have been determined for β-alanyl-β-alanine (bAlabAla) in aqueous solutions of formamide, N-methylformamide, N,N-dimethylformamide and N,N-dimethylacetamide. The measurements were made at 298.15 K and mole fraction of amide x2 = (0–0.35) on the precise “isoperibol” calorimeter. The results obtained have been used to calculate the standard enthalpies of solution (ΔsolH°) and transfer (ΔtrH°) of bAlabAla from water into mixtures as well as the enthalpy coefficients of pairwise interaction (hxy) of the solute with amide in aqueous media. It is established by the interrelation between enthalpy characteristics of bAlabAla dissolution (transfer) and the composition of water–amide binary mixtures.