Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Organic compound containing
Reexamination Certificate
2001-08-16
2002-04-23
Bell, Mark L. (Department: 1755)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Organic compound containing
C502S325000, C502S402000, C502S406000, C502S507000, C524S431000, C428S328000, C428S319300, C428S319700, C428S319900, C428S357000, C428S402000, C428S402240, C428S403000, C428S407000, C424S001290, C424S489000, C987S018000, C252S514000
Reexamination Certificate
active
06376419
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to osmium oxide microencapsulated in an aromatic polyolefin and osmium oxide-chiral ligand complex microencapsulated in an aromatic polyolefin, which makes it possible to conduct an oxidation reaction of organic compounds in an enlarged industrial production scale.
It has been said that, among osmium oxide compounds, only oxides of tetravalent and octavalent osmium are actually existing in separated form, but additionally, oxides of divalent, trivalent and hexavalent osmium may be considered to exist.
The oxides of octavalent osmium have been called osmium tetroxide or osmic acid when it is in an aqueous solution, and the oxides show a strong oxidation ability and thus they have been used as a special oxidizing agent and a catalyst in an organic synthesis. However, osmium tetroxide shows a melting point of 40.6 to 40.7° C., a boiling point of 131.2° C. and vapor pressure of 7 mm at 20° C. (or 52 mm at 55° C.), and has peculiar smell which can be perceived even in such an extraordinary low concentration as 2×10
−5
mg/ml, and further its vapor affects a mucosa of eye, among others, and is toxic to all respiratory organs.
Therefore, use of osmium tetroxide in an industrial scale has been troublesome, and it has been used only as an oxidizing agent for oxidizing a small amount of precious substances. Actually some technologies have been tried for the purpose of using this compound safely in an industrial scale. For instance, International Patent Publication (in Japanese) No. 505884/1992 provides a method for precipitating an osmium oxide on nitrogen-containing polymer from a solvent solution, and actually a product comprising about 1 wt % of osmium tetroxide immobilized on poly(4-vinylpyridine) (e.g. listed on a catalogue of Sigma-Aldrich) has been on the market.
However, in all of those known methods, all basic polymers containing nitrogen atoms, particularly cross-linked ones, have been used to utilize chemical binding effect between the osmium oxide and quaternary nitrogen atoms, and therefore their production has not been easy. Further, when those known compositions are used in actual reactions, the polymers immobilizing the osmium oxide are gradually decomposed under oxidizing conditions (Journal of Molecular Catalysis A: Chemical, vol. 120 (1997) p 203 right column), and therefore the problems upon handling have not yet been solved, and reuse of the compositions is still restricted.
Further, in the product disclosed in the above International Patent Publication (in Japanese) No. 505884/1992, as stated therein, the osmium oxide immobilized on polymer containing nitrogen atoms does not exist in the form of osmium tetroxide but in the form of osmium trioxide or, sometimes, oxide of a polymer or in a reduced form such as oxoanion, and thus it cannot be said that the osmium oxide is immobilized on the polymer as the stable form of osmium tetroxide and consequently the effect as an oxidizing agent of the product is apparently poor as compared with that of osmium tetroxide.
Recently, it is reported that oxidation of olefin compounds by using osmium oxide to which a chiral ligand is attached can give the corresponding chiral products (“Catalytic asymmetric synthesis, VHC Publisher, New York, 1993, P.227-272,” or “Chem. Rev., 94, 2483-2547 (1994),” etc.). But in those asymmetric oxidations, an osmium oxide itself is used without, for instance, immobilized on polymers, etc., and therefore, the recovery and reuse of the osmium oxide is usually difficult.
On the other hand, it is reported that an asymmetric oxidation is conducted using a complex of an osmium tetroxide and a polymer on which a chiral ligand is immobilized (“Eur. J. Org. Chem., 1998, 21-27” etc). However, in this method, introducing of the chiral ligand in the polymer is not so easy and further the polymer containing the chiral ligand thus obtained has to be further reacted with osmium tetroxide. Additionally, the osmium tetroxide in the complex comes off from the complex little by little during the asymmetric oxidation, and therefore reuse of the complex many times is substantially impossible.
SUMMARY OF THE INVENTION
The present inventors have extensively made study in order to solve such problems as mentioned above to realize the improvement, on the basis of which the present invention has been accomplished.
Namely, the present invention provides an osmium oxide composition comprising an osmium oxide microencapsulated in an aromatic polyolefin (hereinafter abbreviated as MCOsO
x
).
Further, the present invention provides MCOsO
x
wherein a chiral ligand further coordinates to an osmium oxide (hereinafter abbreviated as MCOsO
x
-chiral ligand complex).
Still further, the present invention provides a method for preparation of MCOsO
x
, which comprises allowing an osmium oxide to contact with an aromatic polyolefin in an organic solvent, and precipitating MCOsO
x
.
Furthermore, the present invention provides a method for preparing MCOsO
x
-chiral ligand complex, which comprises allowing MCOsO
x
to contact with a chiral ligand.
Still furthermore, the present invention provides a method for preparing MCOsO
x
-chiral ligand complex, which comprises allowing an osmium oxide, a chiral ligand and an aromatic polyolefin to contact with one another in an organic solvent, and precipitating an osmium oxide-chiral ligand complex microencapsulated in the aromatic polyolefin (MCOsO
x
-chiral ligand complex).
Additionally, the present invention provides an oxidizing agent comprising MCOsO
x
.
Still additionally, the present invention provides an oxidizing agent comprising MCOsO
x
-chiral ligand complex.
Still further additionally, the present invention provides a method for preparing a chiral diol compound, which comprises oxidizing an olefin compound with MCOsO
x
-chiral ligand complex.
Still furthermore additionally, the present invention provides a method for preparing a chiral diol compound, which comprises reacting MCOsO
x
, a chiral ligand and an olefin compound with each other.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As the osmium oxide of the present invention, use is generally made of osmium tetroxide, but other osmium oxides such as osmium dioxide can be used. The osmium oxide may be commercially available one.
A part of osmium in MCOsO
x
of the present invention is partly reduced by a small quantity of non-reacted unsaturated bonds usually existed in the aromatic polyolefin, and such partly reduced osmium oxide as above is also included in the osmium oxide of the present invention.
The aromatic polyolefin of the present invention (hereinafter sometimes abbreviated as the polymer of the present invention) includes homopolymers and copolymers which are prepared by polymerization of aromatic olefins, such as, styrene, &agr;-substituted styrene or their ring-substituted derivatives. The substituent in the ring-substituted derivatives of styrene or &agr;-substituted styrene may be any one which does not give bad influence on conducting the microencapsulating of osmium oxide by the method of the present invention and does not reduce the effect of the osmium oxide in MCOsO
x
as an oxidizing agent or a catalyst, and includes an alkyl group such as a methyl group, an ethyl group and an isopropyl group, an alkoxy group such as a methoxy group, an ethoxy group and an isopropoxy group, etc.
The monomer unit other than styrene or &agr;-substituted styrene type unit in the copolymers is not specifically limited and may be any one which does not give bad influence upon conducting the microencapsulating of osmium oxide by the method of the present invention and does not reduce the effect of the osmium oxide in MCOsO
x
as an oxidizing agent or a catalyst, and includes ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid and fumaric acid, ethylenically unsaturated carboxylic acid esters such as methyl acrylate, methyl methacrylate, butyl methacrylate and dimethyl maleate, ethylenically unsaturated amide or imide comp
Armstrong Westerman & Hattori, LLP
Bell Mark L.
Hailey Patricia L.
Kobayashi Shu
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