Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

Enthalpies of the dissolution of d-valine in the mixtures of water with formamide (FA), N-methylformamide (MFA), N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMA) with the mole fraction (x2) of amides ranging up to 0.3 have been measured at T = 298.15 K. The standard enthalpies of the dissolution (solHdeg ) and the transfer enthalpies (trHdeg ) of d-valine have been calculated. On the basis of McMillan Mayer s theory, the enthalpic coefficients of pairwise interaction (hxy) have been calculated. The enthalpic coefficients (hxy) of the solute amide pairwise interaction in the water proved to be positive and increasing in the series: FA less than MFA less than DMF. It is associated with the increasing of the hydrophobic properties of amides and the energy of intermolecular interactions between components of water+organic mixtures in the same sequence.