Mutual diffusion coefficients of some aqueous alkanolamines solutions

The diffusion coefficients of alkanolamines in water at infinite dilution and the mutual diffusion coefficients of aqueous diglycolamine, triethanolamine, 2-amino-2-methyl-l-propanol, and 2-piperidineethanol solutions have been studied by using the Taylor dispersion method. Experimental results for temperatures from (30 to 70) degreesC and at atmospheric pressure as functions of the concentration of alkanolamines from {10.5 to 3 (or 4)} kmol(.)M(-3) are reported. The uncertainty of the measurement is estimated to be +/-2.0%. The diffusion coefficients of alkanolamines in water at infinite dilution were found to vary systematically with the molar mass of the alkanolamines. The obtained mutual diffusion coefficients were correlated by using both a simple relation and the UNIDIF equation. The measured mutual diffusivity data are also well represented by a free-volume expression. The results of this study can be used to develop the kinetic model for gas absorption using aqueous alkanolamine solutions as absorbents.