Diffusion coefficients of substituted benzenes at high dilution in water
- Centre for Environmental Research, Leipzig (Germany). Dept. of Chemical Ecotoxicology
Among the three basic environmental compartments of soil, water, and air, the latter two form the major abiotic dispersion pathways of chemicals, and in unsaturated soil zones it is the pore water that governs vertical leaching of contaminants to the groundwater by advection and diffusion phenomena. The interdiffusion coefficient D{sub aw} of 6 hydrophobic benzene derivatives (a = chlorobenzene, 1,2-dichlorobenzene, 1,4-dichlorobenzene, bromobenzene, 1,2-dibromobenzene, 1,4-dibromobenzene) in aqueous solution (w) at 250 C is measured at different concentrations below 10{sup {minus}5} solute mole fractions using the Taylor dispersion technique. On the basis of the experimental uncertainty around 4%, a distinct concentration dependence is not recognizable. Analysis of the interdiffusion coefficients with the Stokes-Einstein equation shows greater D{sub aw}{sup {infinity}} values than expected from the limit of a complete solute-solvent contact stick limit, and in addition substance-specific deviations. Chemical engineering correlations for D{sub aq}{sup {infinity}} presently available from the literature yield unsatisfactory results for this class of predominantly hydrophobic compounds.
- OSTI ID:
- 201443
- Journal Information:
- Journal of Chemical and Engineering Data, Vol. 41, Issue 1; Other Information: PBD: Jan-Feb 1996
- Country of Publication:
- United States
- Language:
- English
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