Ternary Diffusion Coefficients of 1-Hexanol-Hexane-Toluene and 1-Propanol-Water-Ethylene Glycol by Taylor Dispersion Method

The Taylor dispersion method was used to measure diffusion coefficients of three-component liquid systems. An improved constrained nonlinear least-square method was used to evaluate the ternary diffusion coefficients directly by fitting the mathematical solutions of the dispersion equation to eluted solute peaks detected using a differential refractometer. Diffusion coefficients of the three-component system of acetone-benzene-CCl₄, determined at 25°C, were used to test the procedure. The measured diffusion coefficients were compared with values obtained by optical interferometry and the diaphragm cell method. Ternary diffusion coefficients are also determinated for solutions of 1-hexanol-hexane-toluene and 1-propanol-water-ethylene glycol at 25°C, with an accuracy of approximately 0.05 m²·s^-1.