Vapour pressure and enthalpy of vaporization of cyclic imines

Abstract

© 2018 Elsevier B.V. The vapor pressure of seven-, eight- and nine-membered azacycloalkanes has been measured by the transpiration technique. The enthalpy of vaporization of the compounds was derived using obtained experimental data. A conformational analysis of compounds has been carried out to identify the most stable conformers via the method of molecular mechanics. The enthalpy of formation in the gaseous phase has been calculated for these species using the composite G4 method. The values of the enthalpies of formation in the condensed state have been estimated based on the experimental and calculated enthalpy characteristics of imines. The thermodynamic functions of compounds in the ideal gas state have been computed within the temperature interval 298.15–1500 K. The strain energies of cyclic systems containing carbon and nitrogen in their composition were estimated using quantum chemical methods.