Organic compounds -- part of the class 532-570 series – Organic compounds – Fatty compounds having an acid moiety which contains the...
Patent
1996-04-16
1998-03-31
Geist, Gary
Organic compounds -- part of the class 532-570 series
Organic compounds
Fatty compounds having an acid moiety which contains the...
426417, C11B 300
Patent
active
057340714
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/SE94/00982 filed Oct. 19, 1994.
BACKGROUND OF THE INVENTION
The present invention relates to a process for separating lipophilic compounds from other lipophilic compounds.
Urea (carbamide) and lipophilic compounds, e.g. fatty acids (or derivatives thereof, such as their lower alkyl esters) can under certain conditions form solid urea inclusion complexes (for a review see: D. Swern, "Urea Complexes in Fatty Acids", part III, ed. K.S. Markley, Interscience Publishers 1964). The stability of the complexes are highly dependent on the degree of unsaturation in the fatty acids, saturated fatty acids forming the most stable and polyunsaturated fatty acids forming the least stable complexes. In addition, stability increases with increasing chain length and is reduced by substituents on the fatty acid chain.
Urea crystallisation methodology has for example been used to prepare a concentrate of fish oil ethyl esters enriched in valuable n-3 polyunsaturated fatty acids.
The crystallisation procedure is typically performed by dissolving a mixture of fatty acids (or their derivatives) in a hot alcohol solution containing the appropriate amount of urea. The solution is cooled, whereby solid urea complexes are formed. These are removed by filtration, and after evaporation of the solvents from the mother liquor a fraction enriched in e.g. unsaturated fatty acids is obtained. When urea crystallisation is performed according to this procedure it requires filtration of large amounts of urea complexes and also evaporation of large amounts of solvents to isolate the non-complexing fatty acids. In addition, no simple method has been devised to regenerate the urea.
Japanese patent application JO 2180996-A describes a multistep procedure which allows for regeneration of urea. As mentioned above, crystallisation takes place under conditions where the fatty acids (or their derivatives) are totally dissolved in methanol, but utilises a solvent extraction to isolate the non-complexing fatty acid derivatives (and the fatty, acid derivatives liberated from the complexes by heating). Subsequently, the solvents need to be evaporated. The use of an extraction solvent limits the potential applications, since the components to be fractionated may be difficult to extract.
DESCRIPTION OF THE INVENTION
The object of the present invention is to eliminate the above-mentioned disadvantages in the state of art, and to provide an efficient and economical process for separating lipophilic compounds from other lipophilic compounds by use of a urea crystallisation procedure for purification of lipophilic compounds, e.g. fatty acids and fatty acid derivatives, which allows for continuous regeneration of urea and simple procedures for product isolation, not requiring solvent extraction.
This object of the present invention is achieved by a process as initiallly described, further characterised by said lipophilic compounds are at most only slightly soluble; said urea complex forming lipophilic compounds form complexes with the urea, compounds forming a first phase and the solvent or solvent mixture forming a second phase, where the complexes formed are present as solids in the second phase, and the lipophilic compounds, which have not been complexed with urea, are present in the first phase, phase; lipophilic compounds, thereby forming a two-phase mixture, in which the released lipophilic compounds are present in the upper phase, which is removed and optionally purified, and the urea and the solvent or solvent mixture are present in the lower phase, and, optionally, in the solvent or solvent mixture, and repeating steps a)-g) above one or more times.
Further embodiments of the present invention are given in the subsequent claims.
According to the present invention, it has been found that the urea crystallisation procedure can be performed under heterogeneous conditions using a solvent or solvent mixture, wherein the lipophilic compounds, e.g. fatty acids or derivatives thereof, are at most only slightly soluble. Thi
REFERENCES:
patent: 5106542 (1992-04-01), Traitler et al.
Fex Tomas
Olsson Gunnar
Carr Deborah D.
Geist Gary
Trikonex AB
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