Thomas E. Burchfield

Thermochemical investigations of nearly idela binary solvents. II. Standard heats of solution in systems of nonspecific interactions

Standard heats of solution at 25°C are reported for squalane in mixtures ofn-heptane + iso-octane and in binary mixtures of chloroform, carbon tetrachloride, and cyclohexane; for cyclohexane in chloroform + carbon tetrachloride; and for chloroform in carbon tetrachloride + cyclohexane. General equations based on simple mixing models are developed for the excess thermodynamic properties of a solute at infinite dilution in a binary solvent. For the systems studied, mixing equations based on volume fractions give better agreement than those based on mole fractions, and the agreement is further improved by the use of weighting factors based on the properties of the solute + solvent binary systems.

Thermochemical Excess Properties of Multicomponent Systems: Representation and Estimation from Binary Mixing Data

AbstractA general equation for the estimation of thermodynamic excess properties of multicomponent systems from observed excess properties of the various binary combinations of the components has been developed, based on a simple model of the multicomponent system. This estimation takes the form

Calculation of thermodynamic properties for micelle formation

\Delta \bar Z_{12...N}^{ex} = \sum\limits_{i = 1}^N {\sum\limits_{j > i}^N {(X_i + X_j )(f_i + f_j )(\Delta \bar Z_{ij}^{ex} )^* } }

Model for Thermodynamics of Ionic Surfactants: Effect of Electrolytes on Osmotic and Activity Coefficients

in which

Model for thermodynamics of ionic surfactant solutions. 1. Osmotic and activity coefficients

(\Delta \bar Z_{ij}^{ex} )^*

Model for thermodynamics of ionic surfactant solutions. 3. Enthalpies, heat capacities and volumes of other surfactants

is the molar excess property (enthalpy, entropy, volume, free energy, etc.), of the binary system with components at the same molar ratio as in the multicomponent system, and fi, fj are weighted mole fractions using weighting factors based on the excess properties of the binary systems. The important features of this equation are: it is applicable to a broad range of thermodynamic properties, its application to both integral and differential mixing properties is independent of the manner in which the binary mixing data is represented (Redlich-Kister equation, Wilson equation, etc.), and it provides reasonably accurate predictions ranging from quite good for simple systems of nonspecific interactions to only fair for associated solutions. This equation is recommended as a point-of-departure for mathematical representation of experimental data for multicomponent systems.