Abstract:
A series of p-substituted phenols have been adsorbed from benzene solution on to silica gel.
With the exception ofp-t-butylphenol, limiting adsorptions of the solutes are almost equal in magni
tude and suggest a solute-solvent molecular ratio on the silica surface of 1 : 1. An index of adsorption
Ki, is defined in terms of an ideal model of adsorption at the solid-solution interface and log
is
found to decrease linearly with increase in a, the Hammett p-substituent constant.
Composite adsorption isotherms have been constructed for the adsorption of phenol from a series
of non-polar solvents whose reactivities arc characterised by their Ey values. The isotherms deter
mine, qualitatively, the order of solvent/surface reactivity as n-hexane < cyclohexane < carbon
tetrachloride < toluene < benzene. Quantitatively log A?! is found to decrease linearly with increase
in solvent ET value.
