An experimental investigation of self-diffusion in liquid mixtures ; using the nuclear magnetic resonance spin-echo technique

An experimental investigation of self-diffusion in binary liquid mixtures was conducted using the spin-echo nuclear magnetic resonance technique. Self-diffusion, density, and viscosity data at 25.0°C are reported for the six binary systems consisting of the aromatics: benzene, chlorobenzene, toluene, cumene, aniline, and benzyl alcohol - each in solution with carbon tetrachloride. Data on each binary was obtained at 10, 20, 40, 60, 80, and 100 mole percent concentrations of the aromatic component. Differences in the concentration dependence of the self-diffusion and viscosity coefficients among the six binary systems are qualitatively explained on the basis of formation of hydrogen-bonded associated complexes. The Sutherland-Einstein hydrodynamic diffusion model is shown to provide a reasonably good quantitative description (+/-10%) of the experimental self-diffusion data in mixtures which do not form associated complexes. Its predicative value in associated mixtures is limited to portions of the composition scale where association effects are small.