Vaporization enthalpies at 298.15 K of the n-alkanes from C-21 to C-28 and C-30

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.