ENTHALPY CHARACTERISTICS OF DILUTE-SOLUTIONS OF ACETONITRILE

The enthalpies of mixing of acetonitrile with formamide, N-methylforma mide, N,N-dimethylformamide, and hexamethylphosphoric triamide were me asured in the temperature interval from 283.15 to 328.15 K. The enthal py coefficients of binary and ternary interactions were calculated by the methods of the McMillan-Mayer theory. The contributions to the ent halpy of solution due to the formation of a cavity in the solvent, Del ta(cav)H(o), and those due to the interaction of the solute with the s olvent, Delta(int)H(o), were determined. The enthalpies of the specifi c and non-specific solvation of acetonitrile in the corresponding amid es were calculated. Specific interactions were found to contribute the most to the solvation enthalpy of acetonitrile. The obtained values w ere compared with analogous values for solutions of acetonitrile in wa ter and alcohols.