DETERMINATION OF TERNARY DIFFUSION-COEFFICIENTS BY THE TAYLOR DISPERSION METHOD

A new procedure is described for the rapid determination of ternary mutual coefficients using Taylor dispersion. Pulses of liquid are injected into a long capillary tube containing a laminar flow of liquid of different composition. A differential refractometer at the tube outlet monitors the dispersion of the injected samples. The ternary diffusion coefficients are calculated from the temporal moments of the changes in refractive index. To test the procedure, diffusion coefficients are determined for the three-component systems sucrose + potassium chloride + water and sodium chloride + magnesium chloride + water at 25°C. The measured diffusion coefficients are compared with accurate values obtained by optical interferometry. © 1990 American Chemical Society.