ENTHALPY OF INTERACTION OF SOME ELECTROLYTES WITH DIMETHYL-SULFOXIDE IN WATER AT 298.15 K

Enthalpies of mixing in water of dimethyl sulfoxide with several alkal i-metal halides, Ph4PCl and NaPh4B have been determined by flow microc alorimetry at 298.15 K. Enthalpic pair interaction coefficients, h(NE) , of the virial expansion of the excess enthalpy were calculated. The coefficients are positive for NaF, KF, Ph4PCl and NaPh4B, and negative for the remaining alkali-metal halides. A linear correlation between h(NE) and the anionic radius is observed. Gibbs energy and entropic pa ir interaction coefficients have been calculated from literature data. Single-ion pairwise coefficients have been obtained using the tetraph enylphosphonium tetraphenylborate reference electrolyte assumption.