A comparative study of thermodynamic properties of n-alkane or cycloalkane mixtures with aliphatic, linear or heterocyclic molecules containing the same functional groups

The data available in the literature for the excess Gibbs energies, excess enthalpies, activity coefficients at infinite dilution, and excess heat capacities of heterocyclic tertiary amines, secondary amines and ethers + n-alkanes or + cycloalkanes are examined on the basis of DISQUAC, an extended quasichemical group contribution theory. Using a limited number of adjusted contact interchange coefficients, the model provides an accurate description of the thermodynamic properties as functions of the number of carbon atoms in the heterocycle or in the alkane. The model may serve to predict missing data. The interchange coefficients of the heterocyclic compounds are compared with those of open-chain molecules containing the same functional groups and discussed in terms of intramolecular effects, mainly steric hindrance and ring strain.