The Densities, Viscosities, and Diffusion Coefficients of Solutions of Mono-, Di-, and Triethylamine in Water

The densities, relative viscosities, and diffusion coefficients of the binary systems, monoethylamine–water, diethylamine–water, both at 25 °C, and triethylamine–water at 17 °C, slightly below its lower critical solution temperature, were investigated experimentally.Densities were determined with Ostwald–Sprengel type pycnometers and viscosities by means of Cannon and Fenske viscometer. The diffusion coefficients of the amines in aqueous solution were obtained by the Stokes diaphragm cell method. Monoethylamine has the highest diffusion rate. Plotting D vs. c and extrapolating to c = 0 gives an apparent D 0 which, for all three amines, is notably smaller than the value given by the Nernst model.