Thermodynamics of Tetra-n-octyltin+ hydrocarbon systems by gas-liquid chromatography

Abstract

The activity coefficients of fifteen hydrocarbons at infinite dilution in tetra-n-octyltin were measured using gas-liquid chromatography at five temperatures between 40 and 60°C. Partial molar excess thermodynamic properties are calculated from the experimental results, and discussed within the framework of the equation of state theory of Flory and of the Ising fluid theory of Sanchez and Lacombe. Both theories results in binary mixture characteristic parameters (X12 and ΔP*, respectively) that decrease linearly with the temperature. The results may be interpreted by assuming that there is orientational order in pure tetra-n-octyltin and in pure n-alkanes, but not in the remaining solutes; the destruction of this order on mixing the hydrocarbons with the tin compound results in important contributions to the excess thermodynamic properties.