Correlating multicomponent physical property data with Padé approximants : Part II. Projecting pure component behaviour

Abstract

Physical property data obtained for binary mixtures are conventionally fitted in excess form using the Redlich-Kister equation. The ternary data is then estimated using projections of the binary behaviour on the basis of geometric arguments. It is shown that a more consistent approach entails projection of pure component behaviour onto the simplex region. This generates Padé-type expressions capable of presenting multicomponent data in terms of the pure component temperature dependence using temperature-independent binary parameters. The effectiveness of this concept, for correlating density, viscosity, refractive index and surface tension, was confirmed using ten ternary systems for which data at either three or four different temperatures were available.