Partition coefficients for fatty acid esters in supercritical fluid CO2 with and without ethanol

The complex nature of fish oils was exploited to study the dependence of structural factors upon fatty acid ester solubility in supercritical fluid carbon dioxide (SCF‐CO2). Partition coefficients were determined for a number of components present in two mixtures of fatty cid ethyl esters derived from menhaden oil in SCF‐CO2 at 60°C and 125 bar. Analogous data also were obtained for SCF‐CO2 with 5% (w/w) ethanol added. The addition of ethanol was found to increase partition coefficients for all species, but resulted in a decrease of fluid selectivity. Aside from the chain length of a component, both the degree and position of unsaturation were found to be structural factors that affect the value of the partition coefficient.