The influence of association of alcohol molecules on their adsorption and desorption heats

The paper presents the results of calorimetric measurements and surface excess adsorption isotherms for adsorption process of n-butanol from n-hexane on controlled porosity glasses of different mean pore diameters. The pore diameter was found to have very small effect on the adsorption heat, while it affects the desorption heat recorded by the flow microcalorimeter. Moreover, in the region of very low alcohol concentration in solution, the heat of adsorption exhibits sharp maximum for both narrow and wide pore diameters. This rather puzzling result is attributed to the effect of molecular association of alcohol molecules in the solution.