Extraction of ethyl and methyl esters of polyunsaturated fatty acids with aqueous silver nitrate solutions

Industrial & Engineering Chemistry Research - IND ENG CHEM RES 04/2002; 33(2). DOI: 10.1021/ie00026a026
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    ABSTRACT: A new approach to functionalize triacylglycerol fish oils has been achieved. For the first time, hydrosilylation of various terminal and internal C=C double bonds in ethylenic triacylglycerol was performed under radical initiation sequence, which, after ethanolysis, gave the sol-gel processable triethoxysilyltriacylglycerol P(2). By the use of silyltriflate, new metalated triglycerides P(3), in which silyl fragments are C-bonded in alpha-position to glycerol groups, were synthesized. The sol-gel hydrolysis and polycondensation of triethoxysilyltriacylglycerol led to hybrid materials in which organic and inorganic moieties are covalently linked. These materials open new applications in drug delivery and pharmaceutical formulation.
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    ABSTRACT: In this paper, we demonstrate that the hydrophobic ionic liquid (IL) such as 1-hexyl-3-methyl imidazolium hexafluorophosphate, [hmim][PF6], with silver salt, e.g. AgBF4, is an excellent extraction phase to separate and enrich omega-3 polyunsaturated fatty acid methyl esters (PUFAMEs) from the mixed solution containing closely related saturated, monounsaturated or diunsaturated fatty acid methyl esters. With this silver salt-ionic liquids extraction phase, the health-beneficial omega-3 PUFAMEs such as methyl ester of all-cis-5,8,11,14,17-eicosapentaenoic acid (20:5 or EPA) and methyl ester of all-cis-4,7,10,13,16,19-docosahexaenoic acid (22:6 or DHA) were largely enriched from 18% (wt %) in the original cod liver oil to greater than 80% in the 1-hexene stripping solvent. The unique properties of nonvolatility and adequate polarity allow ILs to dissolve or suspend silver salts and to be conveniently adopted as extraction phase in separating PUFAMEs. The ILs with different hydrophobicities and different silver salts were screened to obtain an optimal combination of IL and silver salt with the highest extraction capability and selectivity. The screening results showed that AgBF4 exhibited high extraction capability in the hydrophobic ILs but little or no extraction capability in the hydrophilic ILs. Furthermore, the high extraction capability of AgBF4 in hydrophobic ILs was much greater than that of AgBF4 in traditional silver-water or silver-alcohol extraction systems. Pretreating the silver-ILs extraction phase with steric hindered short chain olefins could significantly enhance its extraction selectivity for PUFAMEs. Nine runs of the IL-silver extraction phase showed no obvious decrease in its extraction capabilities and selectivities.
    Separation Science and Technology 01/2008; 43(8):2072-2089. · 1.16 Impact Factor
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    ABSTRACT: The liquid–liquid extraction dynamics of an ethyl ester of docosahexaenoic acid (DHA-Et) with silver ion was investigated. The kinetic model was derived according to the following stepwise processes: Diffusion of DHA-Et across the organic film, complex-formation between DHA-Et and silver ion at the interface, and diffusion of extracted complex across the aqueous film. The kinetic parameters for the complex-formation reaction were determined from the investigation with the stirred transfer cell. With the proposed model and determined parameters, we predicted the uptakes of DHA-Et for the extraction system utilizing a slug flow prepared by a microchip. The calculated uptakes showed good correlation to the experimental data. The theoretical investigation suggested that the fast equilibration realized for the slug flow extraction system was due to the large specific interfacial area of the slug caused by the presence of wall film and the thin liquid film caused by the internal circulation. © 2009 American Institute of Chemical Engineers AIChE J, 2010
    AIChE Journal 12/2009; 56(8):2163 - 2172. · 2.58 Impact Factor