Gas–liquid chromatography measured activity coefficients in non-electrolyte solutions

Abstract

Measurements of infinite dilution activity coefficients of six aromatic solutes in each of eighteen solvents at 60°C are reported. It is shown that a combination of Hildebrand–Scatchard and Flory–Huggins equations allows a reasonably quantitative description of the mole fraction based coefficients. The corresponding molarity based coefficients, which may commonly be identical with the volume fraction based coefficients, show substantial independence of solute for a given solvent and, for a given type of solvent the variation is sufficiently small that solute type-solvent type averaged coefficients allow prediction of infinite dilution activity coefficients to better than 10 %. It is suggested that volume fraction based coefficients are likely, for particular solute and solvent types, to be even more closely solute and solvent independent.