A STUDY OF NITRILE GROUP-INTERACTIONS IN ALKANE SOLUTIONS

The molar excess enthalpies, reported in a previous paper, the vapor-l iquid and liquid-liquid phase equilibrium data available in the litera ture, the activity coefficients, the partial molar excess enthalpies a t infinite dilution, and the excess molar heat capacities of n-alkanen itriles + n-alkane or cyclohexane are examined on the basis of the DIS QUAC group contribution model. The quasi-chemical interaction paramete rs for the CN group/n-alkane and CN group/cyclohexane decrease with th e chain length of the nitriles (steric effect). The dispersive paramet ers of all the alkanenitriles investigated, except ethanenitrile, rema in constant. Using a unique set of parameters, the model describes con sistently the thermodynamic properties. The deviations between experim ental and calculated quantities are typical for alkane solutions of ve ry polar compounds.