Ternary diffusion coefficients of 18-crown-6 ether–KCl–water by direct least-squares analysis of Taylor dispersion measurements

Abstract

The Taylor dispersion (peak-broadening) method is used to measure the ternary multicomponent diffusion coefficients of three-component liquid systems. The diffusion coefficients are evaluated directly by fitting the mathematical solutions of the dispersion equation to eluted solute peaks detected by differential refractometry. Tests with sucrose–KCl–water and NaCl–MgCl₂–water indicate that the least-squares treatment is more accurate than a previously reported moments analysis procedure. Ternary diffusion coefficients are also reported for aqueous solutions of 18-crown-6 ether–KCl at 25 °C. The interaction between the solute fluxes owing to the formation of the ether–K⁺ complex is discussed.