Non-additivity in the solvation enthalpies of NH-containing compounds and estimation of their sublimation enthalpies at 298 K

Abstract

© 2017 Elsevier B.V. In the present work, we have developed an additivity scheme for the calculation of solvation enthalpies of NH-containing compounds capable of hydrogen bond formation with solvent. The solvation enthalpies of these compounds were calculated using an additivity scheme and taking into account the contribution due to hydrogen bond formation between solute and solvent. This contribution was calculated using several different equations which connected the enthalpies of hydrogen bonds with frequency shifts of N–H stretching vibrations. The efficiency of the scheme for calculating the enthalpies of solvation was tested on the heterocyclic NH-containing compounds in tetrahydrofuran and 1,4-dioxane. The vaporization and sublimation enthalpies of heterocyclic NH-containing compounds at 298.15 K were estimated using experimentally measured solution enthalpies and estimated values of solvation enthalpies. The vaporization and sublimation enthalpies obtained in the present work are in good agreement with available literature data. The solution enthalpies of nineteen heterocyclic compounds were measured experimentally in the present work.