Solubility in Supercritical Carbon Dioxide

Gomez-Prieto MS, Caja MM and Santa-Maria G. 2002. Solubility in supercritical carbon dioxide of the predominant carotenes in tomato skin. J Am Oil Chem Soc 79(9) 897—902. 

Coimbra P, Blanco MR, Silva HSRC, Gil MH, de Sousa HC. (2006) Experimental determination and correlation of artemisinin s solubility in supercritical carbon dioxide. J Chem Eng Data 51 1097-1104. 

The mole fraction solubilities of ten copper(II) and five chromium(III) P-diketo-nates were measured in SCCO2 with a spectroscopic technique and found to vary over four orders of magnitude. Observed trends indicate that the solubility in supercritical carbon dioxide is strongly dictated by the character of the hydrocarbon or fluorocarbon shell surrounding the central metal atom. A regular solutions approach was used for Cr(acac)°3 to quantitatively attempt to predict the solubility in SCCO2. Solubility... 

Lamb, D. M., Barbara, T. M. Jonas, J. NMR Study of Solid Naphthalene Solubilities in Supercritical Carbon Dioxide Near the Upper Critical End Point. J. Phys. Chem. 1986, 90, 4210M215. 

Other extraction methods used in the lipid extraction include supercritical fluid extraction (SFE) and pressurized liquid extraction (PLE). With SEE, good extraction yields have been obtained for nonpolar lipids including ester-ified fatty acids, acylglycerols, and unsaponifiable matter. However, complex polar lipids are only sparingly soluble in supercritical carbon dioxide alone and polar modifiers, such as methanol, ethanol, or even water is required to improve the extraction of polar lipids (10). SFE has been used for the extraction of lipids especially from various food matrices, such as different nuts, edible oils, and seeds (11). The recoveries of lipids in SFE were on the same levels than with conventional solvent extraction methods (12,13), no significant differences between the fatty acids extracted were observed. PLE has also been used in lipid extraction, although only in very few applications (14). The elevated temperatures used in PLE can cause alteration of the lipid composition. 

Figure 2 shows an example of separating organomercury using supercritical CO2. A 10-m X 50- tm-in-ner diameter SB-Methyl 100 column was used for the separation. Due to their poor solubility in supercritical carbon dioxide, monoorganomercury compounds were derivatized by diethyldithiocarbamate. An interface for a system consisting of SFC and atomic fluorescence spectrometry was developed for the detection of organomercurials. 

The first supercritical fluid-based micronization process has been the rapid expansion of supercritical solutions (RESS) it is based on the solubilization of the solid to be micronized in the SCF and its subsequent precipitation by fast depressurization of the solution. However, the use of this technique is largely limited by the low solubility in supercritical carbon dioxide (SC-CO2) of many of the solids of interest. " ... 

Fig. 6 Enhancement of fish oil solubility in supercritical carbon dioxide by addition of ethanol cosolvent, at 60°C and 250 bar. (From Ref.. )...

This book provides a compilation of the published data on solubility in supercritical carbon dioxide. Data are presented in both tabular and graphical formats. Extrapolation of the data can be performed using the above correlations, that is, the model parameters can be regressed to the available data and then a prediction is made for extended conditions. In the graphs, smooth lines connecting data points are drawn as visual aids these lines are not results of any model correlations. 

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