EXTRACTION OF OIL FROM EMULSIONS

The extraction of lipids from lipoproteins with ether proceeds according to unusual kinetics. The addition of small amounts of ethanol is necessary. It was shown that the same kind of phenomenon may occur when oil is extracted by petroleum ether from emulsions prepared with combinations of charged surfactants. In mixtures of positive and negative surfactants the kinetics of oil extraction proved to be highly complicated. In many cases the extraction of oil is inversely related to the development of a thick interfacial layer. This layer consists of swollen emulsion droplets surrounded by thin layers of a P-coacervate. The kinetics of oil extraction is determined by three factors: (1) the leakage of oil through the P-coacervate; (2) the penetration of petroleum ether into the emulsion droplets; and (3) the maximal amount of stretching of the P-coacervate layer. If the first factor is relatively low and the third relatively high, the oil extraction will at first be low and increase suddenly after a certain time of shaking with petroleum ether. It is suggested that the same type of mechanism results in the S-curve relating lipid extraction and time in lipoprotein extraction. © 1969.