PHASE-EQUILIBRIA OF UREA-FRACTIONATED FISH-OIL FATTY-ACID ETHYL-ESTERS AND SUPERCRITICAL CARBON-DIOXIDE

Measurements of phase equilibria of urea-fractionated fish oil fatty a cid ethyl esters (FAEEs) in supercritical carbon dioxide were performe d at pressures from 8 to 26 MPa and temperatures of 313.2 and 343.2 K. Experimental temperatures, pressures, and mass fractions are reported in tabular form. The equilibrium ratios of the esters depend strongly on the system pressure and temperature, and a comparison with previou s equilibrium measurements on the fatty acid ethyl ester mixture befor e the urea fractionation shows that they also depend on the compositio n of the ester mixture. The data show that high selectivity and low so lubility are obtained at low operating pressures, while at high operat ing pressures the selectivity is low but the solubility is high. Twent y-nine components corresponding to more than 90 % of the natural mixtu re are identified. The three polyunsaturated FAEEs, C18:4n3, C20:5n3, and C22:6n3, correspond to more than 80% of the urea-fractionated mixt ure.