Limiting interdiffusion coefficients of benzene, toluene, ethylbenzene and hexafluorobenzene in water from 298 to 368 K

Abstract

The interdiffusion coefficients of benzene, toluene, ethylbenzene and hexafluorobenzene have been measured in water at concentrations close to infinite dilution and temperatures between 298 and 368 K. In the temperature range 323–368 K the activation energy for diffusion is 16.1 ± 0.7 kJ mol^–1 for all the solutes studied, significantly smaller than that in the lower temperature range. When the data are compared with those in organic solvents, the Stokes–Einstein coefficients (f=kT/Dπηr) for the solutes are larger in water even at 368 K. The results are discussed in relation to the three-dimensional hydrogen-bond network of water.