THERMODYNAMICS STUDY ON SELF-ASSOCIATION OF ALCOHOLS IN AROMATICS BY FREEZING-POINT DEPRESSION

The solvent activity coefficients gamma-B of binary mixtures have been measured for C1 to C-4 alcohols in benzene and in p-xy e e by freezing point depression. The data was treated with Wiehe-Baglsy association model combining with a Hildebrand-Scatchard term. The association constants K(A) and infinite dilution activity coefficients gamma-A-infinity of alcohols have been evaluated. It is found that the K(A) of alcohols in each solvent follow the order, methanol > ethanol > n-propanol > n-butanol; n-propanol > iso-propanol; n-butanol > iso-butanol > tert-butanol greater-than-or-equal-to sec-butanol. And the value of K(A) of each alcohol in p-xylene is greater than in benzene. The gamma-A-infinity of alcohols in each solvent decrease in the following order, methanol > ethanol > n-propanol > n-butanol; n-propanol > iso-butanol. And the value of gamma-A-infinity of each alcohol in benzene is greater than in p-xylene.