Using supercritical fluid chromatography to determine diffusion coefficients of 1,2-diethylbenzene, 1,4-diethylbenzene, 5-tert-butyl-m-xylene and phenylacetylene in supercritical carbon dioxide.

The binary diffusion of 1,2-diethylbenzene, 1,4-diethylbenzene, 5-tert-butyl-m-xylene and phenylacetylene at infinite dilution in supercritical carbon dioxide were measured between 15.0 and 35.0 MPa and in the temperature range of 313.16 to 333.16K by the Taylor-Aris chromatographic method. The effect of temperature, pressure, viscosity and density was discussed. In the case of temperature dependence, additional measurements were done for 5-tert-butyl-m-xylene from 308.16 to 398.16K at 35.0 MPa. The measured diffusivities of the four solutes were compared with the calculated ones by several predictive formulas.