The concentration dependence of the mutual diffusion coefficients in the ternary liquid mixture glycerol + acetone + water is determined at 298.15 K by the Taylor dispersion technique along two concentration paths of constant water mole fractions of 0.468 and 0.420, ranging from the binary subsystem toward the phase boundary in the vicinity of the critical solution point. The eigenvalues of Fick's diffusion coefficient matrix are given, and the influence of the optical properties of the system on the diffusion coefficient determination is discussed. It was found that the determinant |D| continuously declines on approaching the phase boundary.

Previous work has shown that mixtures of multiple phospholipids with cholesterol exhibit phase behavior which may be approximately modeled by a hypothetical binary mixture of cholesterol and an "average"phospholipid. 1 This study presents a detailed thermodynamic model of such multicomponent mixtures based on regular-solution theory. When the individual phospholipids are treated independently, calculated phase behavior shows systematic deviations from the average-phospholipid model. These deviations may be expressed concisely in terms of the distribution of binary critical parameters of the individual phospholipids, and the deviations are small for mixtures in which the individual phospholipids exhibit similar phase behavior in binary mixtures with cholesterol.