Vaporization Enthalpies at 298.15 K of the n-Alkanes from C₂₁ to C₂₈ and C₃₀

The vaporization enthalpies of the n -alkanes reported previously in the literature are corrected to 298.15 K and compared to vaporization enthalpies obtained from correlation-gas chromatography. The vaporization enthalpies at 298.15 K for C 21 −C 28 and C 30 are critically evaluated, and the accuracy of measurements derived from some recent torsion effusion measurements is questioned. A series of vaporization enthalpies consistent with the gas chromatographic results are obtained which correlate with the number of carbon atoms in the molecule. The following vaporization enthalpies in kJ·mol - 1 at 298.15 K are recommended: heneicosane, 107.3 ± 2.5; docosane, 113.7 ± 0.3; tricosane, 118.5 ± 0.4; tetracosane, 125.6 ± 2.7; pentacosane, 126.9 ± 1.4; hexacosane, 139.1 ± 7.7; heptacosane, 145.6 ± 8; octacosane, 151.4 ± 8.4; triacontane, 162.1 ± 8.0.