Surface tension of perfluoropropane, perfluoro-n-butane, perfluoro-n-hexane, perfluoro-octane, perfluorotributylamine and n-pentane. Application of the principle of corresponding states to the surface tension of perfluoroalkanes

Abstract

The orthobaric surface tensions of C₃F₈, n-C₄F₁₀, n-C₆F₁₄, C₈F₁₈, (C₄F₉)₃N and n-C₅H₁₂ have been measured by the differential capillary-rise technique over various ranges of temperatures. The results for the perfluoroalkanes have been analysed in terms of the van der Waals equation, the Brock and Bird equation incorporating Pitzer's acentric factor and the phenomenological corresponding-states treatment of Patterson and Rastogi; the data are fitted with varying degrees of success. The phenomenological principle of corresponding states to which the surface tensions for the perfluoroalkanes conform is not identical to that for the n-alkanes and some other homologous series, but it is similar to it, in particular in the need for at least three reduction parameters.