TEMPERATURE-DEPENDENCE OF THE SURFACE-TENSION FOR BINARY-MIXTURES OF N-BUTANENITRILE PLUS N-ALKANES

The differential capillary-rise method was used to determine the orthobaric surface tension of binary liquid mixtures of n-butanenitrile mixed with n-pentane, n-hexane, and n-heptane, throughout the composition range, at 293.15, 303.15, 313.15, 323.15, 333.15, and 343.15 K. Furthermore, the system with n-hexane was also studied at 263.15 K, i.e., 19 K above its upper critical solution temperature, over the whole composition range. For each binary system the surface tension changes regularly with both temperature and composition between the values of the pure components. The results are discussed in terms of deviations from surface ideality and related to the large positive deviations observed for bulk properties of the same systems.