Calculation of Heats of Vaporization of Long Chain Molecules by Group Contribution Method

Benson's additivity rule has been used to compute the heat of vaporization $(\Delta H^o$$_{v})$ of long chain molecules includes n-alkylcyclopentanes, and n-lkylcyclohexanes and n-alkylbenzenes. From the error analysis empirical equations have been obtained which accurately predicts the $\Delta H^o$$_{v}$ of these substituted n-alkanes. For simple n-alkanes it is observed that no modification is necessary in Benson's method. The present simple and elegant empirical approach can be utilized to calculate other thermodynamic properties of long chain molecules where such data are generally scarc