SOLUBILITIES OF FATTY-ACIDS, FATTY-ACID ESTERS, TRIGLYCERIDES, AND FATS AND OILS IN SUPERCRITICAL CARBON-DIOXIDE

Using supercritical carbon dioxide (SC-CO2) as the solvent, the solubi lity of methyl esters, ethyl esters, fatty acids, triglycerides, and f ats and oils were studied over a range of temperature and pressures. E quilibrium data from the literature were correlated using the Peng-Rob inson equation of state with the van der Waals (VDW) and Panagiotopoul os and Reid (PR) mixing rules. The data were also correlated using sta tistical methods and the solubilities predicted by various models were compared with experimental solubilities at the temperature and pressu re conditions studied. The equation of state method provided good agre ement of theory with experiment for the solubilities of fatty acids an d their esters, but less so for the triglycerides, fats and oils. The statistical methods on the other hand, not only predicted the solubili ties of fatty acids and fatty acid esters well, but also gave good agr eement with the solubilities of triglycerides, fats and oils. Chain le ngth, degree of unsaturation, and functional groups in compounds are k nown to affect the vapor pressures of these compounds which in turn in fluence their solubilities in SC-CO2. As expected solubilities decreas ed in going from fatty acid esters, to fatty acids, to triglycerides.