Sublimation Vapor Pressures as Evaluated by Correlation-Gas Chromatography

Vapor pressures of the liquid phase obtained by correlation-gas chromatography are used in conjunction with experimental fusion enthalpies to calculate sublimation vapor pressures of a number of compounds including n-alkanes, polyaromatic hydrocarbons, aromatic heterocyclic compounds, and polycyclic hydrocarbons Vapor pressures at the fusion temperature, T(fus), calculated from vapor pressure equations generated by this technique and obtained by extrapolation, are used to evaluate vaporization enthalpies at T(fus). The sublimation enthalpy at T(fus), is obtained from the sum of the experimental fusion enthalpy and vaporization enthalpy The vapor pressure at T(fus),, used as an approximation of the triple-point vapor pressure, combined with the sublimation enthalpy and a heat capacity adjustment is used to calculate sublimation vapor pressures as a function of temperature Calculated sublimation vapor pressures extrapolated to near ambient temperatures compare with experimental values to within a factor of three