LIQUID EQUILIBRIA IN SYSTEM METHYL OLEATE-METHYL PALMITATE-ACETONITRILE-HEXANE - SIGNIFICANCE IN CRAIG COUNTERCURRENT EXTRACTION

The system methyl oleate-methyl palmitate-acetonitrile-hexane was studied at 25° C. Although consisting of pure components, this system is typical of systems in which an attempt is made to separate lipids by countercurrent distribution. Equilibrium surfaces were determined by cloud point titrations. Tie lines were determined by a combination of weighing, gas chromatographic, and graphical techniques. A vector method was used to organize the data and to calculate tie-line segments and is applicable to any multicomponent heterogeneous system. The ratio of tie-line segments agreed with the ratio of experimentally determined phase masses within 2%. In a countercurrent distribution using this system, large deviations from ideality would occur. As solute was added to the system, solvent intersolubilities changed. Partition coefficients were shown to be a function of the total composition of the system and varied with ester concentration. The partition coefficient of a given methyl ester was influenced by the presence of the other methyl ester in the system. In addition, an isopycnic region, where the phases invert, was observed. © 1969, American Chemical Society. All rights reserved.