Diffusion coefficients of metal acetylacetonates in supercritical carbon dioxide

Binary diffusion coefficients, D12, of the metal acetylacetonates, palladium(II) acetylacetonate and cobalt(III) acetylacetonate, were measured from 308.2 to 343.2 K over the pressure range from 9 to 40 MPa at infinite dilution in supercritical carbon dioxide using the chromatographic impulse response method. The effects of pressure, temperature, density, and viscosity on D12 values were examined. It was observed that the D12 values of palladium(II) acetylacetonate and cobalt(III) acetylacetonate were larger than those of lipids with similar molecular weights, such as arachidonic acid and monoolein, respectively. Furthermore, the measured D12 data of each metal acetylacetonate were well correlated by the hydrodynamic equation D12/T as a function of carbon dioxide viscosity.