ISSN:
1572-9567
Keywords:
benzene
;
carbon dioxide
;
critical behavior
;
data comparison
;
diffusion coefficient
;
diffusivity
;
peak shape
;
supercritical fluids
;
Taylor dispersion
;
toluene
;
transport coefficients
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract This paper describes some of the experimental and theoretical problems encountered when the Taylor dispersion method is applied to the measurement of diffusion coefficients near gas-liquid critical points. We have used our own measurements of diffusion of benzene and toluene in supercritical carbon dioxide, along with measurements from several other sources, to illustrate some of the experimental challenges. Special attention is given to the peak shape. The intercomparisons are greatly simplified by comparing the experimental data as functions of density, rather than pressure. We find large and unexplained discrepancies between the various experimental sources. We discuss the theoretical predictions for the relationships between the diffusion coefficients and diffusivities obtained from Taylor dispersion and dynamic light scattering in fluids near critical points. We conclude that there is no strong reason to press for Taylor dispersion measurements near the gas-liquid critical point of the carrier gas.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00502114
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