The vapor pressure of n-alkanes revisited. New high-precision vapor pressure data on n-decane, n-eicosane, and n-octacosane

The authors report new vapor pressure measurements on n-decane (268-490{Kappa}), n-eicosane (388-626{Kappa}), and n-octacosane (453-575{Kappa}) made with a modified ebulliometer and an inclined piston gauge. Benzene and water were the standards in the ebulliometric measurements on n-decane and n-eicosane, while n-decane was the standard for the measurements on n-octacosane. The high-quality data for n-decane, which were confirmed by a third-law'' analysis, suggest that reported literature data are in error. Similar concerns are raised about reported n-eicosane data. The vapor pressure data were regressed with the Cox equation, using as reference the normal boiling point.