(326o) Extraction Dynamics of Ethyl Ester of Docosahexaenoic Acid with Silver Ion with Slug Flow Prepared by Microreactor

Over the last several decades, N-3 polyunsaturated fatty acids (PUFA) such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) have been widely noticed for human health. They are contained in fish oils with many other fatty acids. Therefore, purified and concentrated N-3 PUFA which is separated from the other PUFA and saturated fatty acids has to be used for the medical supplies and food additives. For separation and purification of PUFA, liquid-liquid extraction of PUFA ethyl ester (PUFA-Et) with silver ion has attracted attention and has been expanded into more effective systems utilizing supported liquid membrane, emulsion liquid membrane and slug flow prepared by microchip. Among these techniques, we have directed our attention to utilizing slug flow prepared by microchip. Recently, we investigated the extraction of DHA-Et and EPA-Et with the slug flow prepared by T-shape microchip and achieved ultra fast and effective extraction of them. In this study, we carried out a kinetic investigation of DHA-Et extraction with silver ion as the extractant. We used a stirred transfer cell to investigate the extraction rate of DHA-Et. The effect of stirring speed, DHA-Et concentration, silver ion concentration and temperature on initial extraction rate was measured. From the knowledge, we determined the kinetic parameters for complex-formation reaction between DHA-Et and silver ion. In addition, the overall rate equation containing the diffusion resistances of DHA-Et across the liquid laminar film near the interface between aqueous and organic phases was proposed in order to predict the uptake curves of DHA-Et extraction. The calculated uptake curves showed good correlation to the experimental data for the extraction of DHA-Et with the stirred transfer cell and for the ultra fast extraction of it with slug flow prepared by T-shape microchip. By comparing the calculated and experimental uptake curves resulted for the slug flow system, we discuss the characteristic of slug flow and estimate the influential parameter in the ultra fast extraction. The theoretical investigation suggested that the ultra fast extraction realized for the slug flow system is due to the large specific interfacial area of the slug caused by the presence of wall film and the thin liquid laminar film adjacent to the interface caused by the internal circulation.