TEMPERATURE-DEPENDENCE OF INTERFACIAL-TENSION BETWEEN NORMAL ORGANIC-ACIDS AND WATER

The interfacial tensions between normal organic acids and water are me asured versus temperature, using either the Wilhelmy (plate) method, o r the Du Nouy (ring) method. The studied liquid-liquid binary two-phas e systems are aqueous mixtures of n-organic acids with a number of car bon atoms ranging from five to fourteen. In all cases the interfacial tension decreases linearly with temperature in the operating temperatu re range (room-80 degrees C). Such a ''normal'' behavior is quite intr iguing, because the interfacial tensions for the corresponding. alcoho l series show a parabolic-like temperature dependence, while interfaci al tension is linearly increasing with temperature in the case of the corresponding amine series. (C) 1994 Academic Press, Inc.