The solvent activity coefficients gB of binary mixtures have been measured for C1 to C4 alcs. in benzene and in p-xylene by f.p. depression. The data was treated with Wiehe-Bagley association model combining with a Hildebrand-Scatchard term. The association constants KA and infinite dilution activity coefficients gA?of alcs. have been evaluated. The KA of alcs. in each solvent follow the order, methanol > ethanol > n-propanol > n-butanol; n-propanol > isopropanol; n-butanol > isobutanol > tert-butanol ?sec-butanol. And the value of KA of each alcohol in p-xylene is greater than that in benzene. The gA?of alcs. in each solvent decrease in the following order, methanol > ethanol > n-propanol > n-butanol; n-propanol > isobutanol. And the value of gA?of each alcohol in benzene is greater than that in p-xylene.

Key words: ETHANOL, BENZENE, METHANOL, DIMETHYLBENZENE, FREEZING POINTS, BUTANOL, ACTIVITY, SOLVENT EFFECT, ENTROPY, ASSOCIATION