Phase Equilibria of Urea-Fractionated Fish Oil Fatty Acid Ethyl Esters and Supercritical Carbon Dioxide

Abstract

Measurements of phase equilibria of urea-fractionated fish oil fatty acid ethyl esters (FAEEs) in supercritical carbon dioxide were performed 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 tubular form. The equilibrium ratios of the esters depend strongly on the system pressure and temperature, and a comparison with previous equilibrium measurements on the fatty acid ethyl ester mixture before the urea fractionation shows that they also depend on the composition of the ester mixture. The data show that high selectivity and low solubility are obtained at low operating pressures, while at high operating pressures the selectivity is low but the solubility is high. Twenty-nine components corresponding to more than 90% of the natural mixture are identified. The three polyunsaturated FAEEs, C 18:4n3 , C 20:5n3 , and C 22:6n3 , correspond to more than 80% of the urea-fractionated mixture