A simple and inexpensive technique to measure molecular diffusion coefficients

Abstract

The experiment proposed is simple and inexpensive and provides an accurate method for measurement of the molecular diffusion coefficient, D-m. It is a novel method that has the added advantage of easily providing data at temperatures and pressures that differ significantly from ambient values. The experimental results for naphthalene in air are in excellent agreement with the experimental values of the molecular diffusion coefficient measured by other authors. Experimental measurements of mass transfer in water were also carried out for a range of the relevant parameters. The soluble spheres used in the experiments were made of either benzoic acid or 2-naphthol, and the ranges of temperatures covered were 293-333 and 293-373 K, respectively. Using the mass transfer theory presented in this work, the molecular diffusion coefficient of the two solutes was determined, and good agreement with literature values was found.