Enthalpies of vaporization of N,N-dialkyl monamides at 298.15 K

Abstract

Enthalpies of vaporization of several N,N-dialkyl monamides have been measured by correlation gas chromatography. The enthalpy values of the compounds are derived by an extrapolative method using the known enthalpy of vaporization values of basic amides at 298.15 K, used as standards. First order molecular connectivity valence indices of these amides ( 1 χ ν ) as described by Kier and Hall have been evaluated and are found to have an excellent correlation with measured enthalpies of vaporization in addition to several other indices, such as, solvent accessible surface area (SAS), molecular surface area (MSA) and solvent excluded volume (SEV). The quantitative structure–property relationship (QSPR) approach is used to predict the enthalpies of vaporization from molecular connectivity valence index.