Organic compounds -- part of the class 532-570 series – Organic compounds – Fatty compounds having an acid moiety which contains the...
Reexamination Certificate
1999-01-22
2001-11-13
Carr, Deborah D. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Fatty compounds having an acid moiety which contains the...
C554S191000, C502S082000, C502S055000, C502S086000, C210S198200
Reexamination Certificate
active
06316647
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a cation-exchanged clay mineral, a packing material for chromatography using the same and a method of producing the same. More particularly, the present invention relates to an improvement of an exchanging cation thereof.
BACKGROUND OF THE INVENTION
Chromatography is generally used for the analysis or separation and refinement of various substances. Liquid chromatography is divided largely into adsorption chromatography and partition chromatography according to the separation mechanism.
Partition chromatography is further divided into normal-phase partition chromatography and reversed-phase partition chromatography according to the polarities of the elute and the packing material.
Most of the packing materials used for adsorption chromatography and normal-phase partition chromatography are totally porous silica gel packing materials in which macropores and micropores are dispersed reticulately. Alternatively, inorganic supports such as alumina and porous glass materials, and porous polymers such as polystyrene-divinyl benzene, polyvinyl alcohol and polyhydroxy methacrylate are used. Calcium hydroxide powder, calcium phosphate gel, etc. are also used for specific purposes.
Above-described chromatographic supports (e.g., silica gel) modified with alkyl groups, such as octadecyl groups, are often used for reversed-phase chromatography.
Other packing materials are also used, for example, packing materials for cation-exchange liquid chromatography such as silica gel or a porous polymer with a compound having a sulfonyl group or carboxyl group combined therewith and packing materials for anion-exchange liquid chromatography such as silica gel or a porous golymer with a quaternary ammonium or a diethylamino group combined therewith.
All of these packing materials, however, suffer from various problems. Especially, the discrimination between saturation and unsaturation is so poor that the discrimination between substances having similar molecular weights is very difficult. An improvement at this point has therefore been in strong demand.
As a packing material for meeting such a demand, the present invention developed a packing material disclosed in Japanese Patent Laid-Open No. 199155/1989.
This packing material is a swelling clay mineral with the ions between layers substantially replaced by cations other than sodium ions, especially, silver ions. Since this packing material has discrimination between saturation and unsaturation, it is possible to separate a wide variety of unsaturated compounds into substances according to the degree of unsaturation. The packing material is therefore used as a means of analyzing and separating various compounds.
Even this packing material composed of the clay mineral, however, very strongly adsorbs a highly unsaturated compound having a degree of unsaturation of not less than 3, and the peak in chromatography becomes broad, which makes efficient and short-time analysis and separation impossible.
In addition, a poor reproducibility of retention time in certain solvents has been a big problem.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to eliminate the above-described problems in the related art and to provide a packing material for chromatography which has a high resolution, especially, with respect to an unsaturated compound and an excellent time stability, and a cation-exchanged clay mineral can be used as the packing material.
As a result of studies undertaken by the present invention so as to achieve this aim, it has been found that the problem of a broad peak of a highly unsaturated compound and the problem of the poor reproducibility of retention time of an unsaturated compound can be solved when a low-valence metal existing between layers of a clay mineral is an ammine or amine complex. On the basis of this finding, the present invention has been achieved.
To state this concretely, it was found that the low-valence metal ions such as silver ions existing between layers of a clay mineral not only exist in the form of ions but also are oxidized or reduced when they come into contact with a solvent. In other words the existing state of the ions changes, and this is the main cause of a broad peak and a wide variety of the holding time of a highly unsaturated compound.
For example, it was confirmed as a result of X-ray analysis that the monovalent silver ions existing between layers of a clay mineral are oxidized into silver oxide at a high temperature, or by a solvent or reduced into metal silver.
It was also confirmed that the monovalent copper ions which are considered to show a discrimination between saturation and unsaturation in the same way as silver are easily oxidized into divalent copper ions when these are dried. The divalent copper ions do not separates unsaturated substances anymore.
The present inventors therefore paid attention to the existing form of the low-valence metal ions which exist between layers of a clay mineral.
In a first aspect of the present invention, there is provided a cation-exchanged clay mineral comprising a swelling clay mineral with spherical shape and the cations between layers substantially replaced by low-valence metal amine complexes and/or low-valence metal ammine complexes.
A packing material for chromatography provided in a second aspect of the present invention comprises a cation-exchanged clay mineral provided in the first aspect of the present invention.
A clay mineral provided in a third aspect of the present invention is characterized in that the low-valence metal amine complex is represented by the general formula: [M(NH
3
)
1-3
]X (wherein M is a metal, and X is an anion).
In a clay mineral provided in a fourth aspect of the present invention, M is monovalent copper, silver or gold.
A vessel in a fifth aspect is characterized in that the packing material is said clay mineral. The vessel is preferably a column shape.
In a sixth aspect of the present invention, there is provided a method of producing a cation-exchanged clay mineral comprising the steps of immersing a swelling clay mineral in an ammonia alkali ammonium ion solution, drying the swelling clay mineral, and immersing the dried swelling clay mineral in a low-valence metal amine complex solution and/or a low-valence metal ammine complex solution so as to substantially replace the cations between layers by the low-valence metal amine complexes and/or the low-valence metal ammine complexes.
In a method of producing a cation-exchanged clay mineral provided in a seventh aspect of the present invention, the clay mineral immersed in the low-valence metal amine complex solution and/or the low-valence metal ammine complex solution is further heated.
In a eighth aspect of the present invention, there is provided a method of separating or collecting unsaturated compound by using a packing material obtained by substantially replacing the cations between layers of a swelling clay mineral by low-valence metal amine complexes and/or low-valence metal ammine complexes.
In a method of separating fish oil and fat provided in an ninth aspect of the present invention, a fatty acid ester obtained by hydrolyzing and further esterifying fish oil and fat is used as an object of separation of decosahexaenoic acid.
In a method of separating unsaturated compound provided in a tenth aspect of the present invention, a supercritical fluid is used as a solvent.
The above and other objects, features and advantages of the present invention will become clear from the following description of the preferred embodiments thereof, taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 5145578 (1992-09-01), Tokubo et al.
Chem. abstr. vol. 114, No. 11, p. 241, Yamada et al “Preparation and properties of antibacterial clay interlayer compound”, 1991.
Kadota Yasuhiko
Ohtsu Yutaka
Tanaka Isao
Yamaguchi Michihiro
Carr Deborah D.
Shiseido Company Ltd.
Townsend & Banta
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