Enthalpies of l-proline dissolution in aqueous solution of N,N-dimethylformamide at 293.15–308.15 K

Abstract

The enthalpies of l-proline dissolution in aqueous solution of N,N-dimethylformamide (DMF) with a mole-fraction of DMF from x2=(0–0.2) have been measured at 293.15–308.15K. The results obtained have been used to calculate the standard enthalpies of solution (ΔsolH°) and transfer (ΔtrH°) of l-proline from water into mixtures as well as the enthalpy coefficients of pairwise interaction (hxy) of the solute with DMF in aqueous medium. The interconnection between enthalpy characteristics of l-proline dissolution (transfer) and the composition of (H2O+DMF) mixture and its temperature have been established. The resulting data have been compared with those obtained before for some amino acids with cyclic side-chain: l-phenylalanine and l-tryptophan in the same mixed solvent at 298.15K has been made.