A group contribution model for determining the sublimation enthalpy of organic compounds at the standard reference temperature of 298 K

The sublimation enthalpy provides a measure of molecular interactions in the solid phase. Practical applications involving sublimation enthalpies include the estimation of the crystal lattice energy of molecular crystals, estimation of the enthalpy of solvation of crystalline organic compounds, and prediction of the environmental fate and vapor pressures of solid compounds. Recently an extensive compilation of phase change enthalpies, including sublimation enthalpies of pure organic and organometallic compounds, was published [1]. This collection of sublimation enthalpies for 1269 compounds at the standard temperature of 298.15 K was used in this study for the development of a predictive model. The compounds in the collection are composed of carbon, hydrogen, nitrogen, oxygen, phosphorous, sulfur, fluorine, chlorine, bromine, and iodine. This paper presents a reliable group contribution model for the estimation of the sublimation enthalpies of organic compounds. The group contribution model developed is able to predict the standard molar enthalpies of sublimation to within an average absolute relative deviation of 6.4%, which is of sufficient accuracy for many practical applications.