Vapor Pressures and Vaporization Enthalpies of the n-Alkanes from C21 to C30 at T = 298.15 K by Correlation Gas Chromatography

Abstract

The temperature dependence of gas-chromatographic retention times for hentriacontane to octatriacontane is reported. These data are used in combination with other literature values to evaluate the vaporization enthalpies and vapor pressures of these n-alkanes from T = 298.15 to 575 K. The vapor pressure and vaporization enthalpy results obtained are compared with existing literature data where possible and found to be internally consistent. The vaporization enthalpies and vapor pressures obtained for the n-alkanes are also tested directly and through the use of thermochemical cycles using literature values for several polyaromatic hydrocarbons. Sublimation enthalpies are also calculated for hentriacontane to octatriacontane by combining vaporization enthalpies with temperature adjusted fusion enthalpies.