Hydrophobic hydration from solubilities of aliphatic hydrocarbons in water

The internal standard transfer Gibbs energy, ∆G0t,int is computed by subtracting corresponding standard transfer Gibbs energy, ∆G0t of solute hydrocarbons due to cavity and different interactions from the total ∆G0t value as obtained from the available experimental solubility of them in water (w). For alkanes other possible interaction effects being negligibly small, ∆G0t,int is a direct measure of hydrophobic hydration. The various ∆G0t, int values of > CH2 group evaluated from the difference of ∆G0t,int values of two successive members of homologous alkanes, is found to be highly precise in respect to their average, 3.95 kJ mol− 1, indicating additive nature of the parameter. ∆G0t,int values of different fractions are found to follow the order: -CH3 > -CH2- ≫ CH- ≫ C <. Aliphatic hydrocarbons possessing the same number of C atom follows the sequence: alkane > alkene > alkyne, according to their reverse order of polarizability and acidity in water.