Abstract: The activity coefficients of solvent for some phenols, i.e.p-cresol, m-cresol, o-cresol, 2,4-dimethyiphenol, 2,6-dimethylphenol and phenol mixtures p-cresol+m-cresol, p-cresol+o-cresol, m-cresol+o-cresol, 2,4-dimethylphenol+2,6-dimethylph-enol (1:1 mole ratio) in benzene and in p-xylene have been measured by freezing point depression. The data was treated with Wiehe-Bagley association model combining with a Hildebrand-Scatchard term to evaluate the association constants K_A of phenols. It is found that the K_A of phenols in each solvent follows the order: p-cresol>m-cresol>0-cresol; 2,4-dimethylphenol>2,6-dimethylphenol. The association constants of binary solute mixtures are all situated between the respective two pure components.

Key words: Phenols, Aromatics, Freezing point depression, Selfassociation