Chemistry of inorganic compounds – Oxygen or compound thereof – Metal containing
Reexamination Certificate
1999-02-03
2001-02-06
Dunn, Tom (Department: 1754)
Chemistry of inorganic compounds
Oxygen or compound thereof
Metal containing
C423S599000, C502S324000, C502S325000, C502S326000, C502S338000, C502S340000, C502S344000, C502S353000
Reexamination Certificate
active
06183717
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to transition metal oxide-containing materials and, more particularly, to vanadium oxide-containing compositions and the rational synthesis thereof.
Transition metal oxide surfaces are known to serve as catalytic surfaces for a large number of important industrial chemical transformations. The mechanism of their interaction with substrate molecules, however, is generally not well understood due mainly to the complex nature of these poorly characterized surfaces that are generally inaccessible to various physical chemical analytical techniques. As a result, the suitability of particular catalytic surfaces for specific processes is currently commonly determined empirically with practically little or no possibility of systematic improvements in the performance of such catalytic materials.
As will be appreciated, numerous environmental and technological challenges exist for the application of such catalytic materials. Such challenges range from and include the removal of toxic materials from automotive vehicle exhaust and industrial flue streams, selective or controlled oxidation of hydrocarbons, photochemical conversion of water into H
2
and O
2
, synthesis of gasoline from synthesis gas (also referred to as “syn-gas”), cost-effective nitrogen fixation, preparation of food stuffs and drugs, and removal of urea from blood, for example.
Polyoxometalates or transition metal oxide clusters (such as of vanadium, molybdenum and tungsten, for example) and their derivatives provide remarkably diverse and well-defined building blocks generally believed well suited for use in generating or assembling nanosized molecular systems. Recently, conventional organic and inorganic ligands (e.g., PO
4
3−
, AsO
4
3−
, SO
4
2−
, etc.) have been used to join together or “glue” metal oxide moieties to prepare supramolecular structures and solids. Such ligands, however, generally have only limited thermal stability and may be scarce.
In view of the above, there is a need and a demand for a rational synthesis of well characterizable metal oxide surfaces with desired features—with and without immobilized catalytic active groups (such as metal ions, cluster compounds, organometallic fragments, asymmetric ligands, enzymes or cells, for example) such as may be helpful or useful in the satisfaction of one or more environmental or technological requirements such as described above.
SUMMARY OF THE INVENTION
A general object of the invention is to provide for the rational synthesis of transition metal oxide-containing materials and the materials resulting therefrom.
A more specific objective of the invention is to overcome one or more of the problems described above.
The general object of the invention can be attained, at least in part, through a composition represented by the chemical formula:
(Cat)
m
[M
a
V
18
O
42
XL
3z
]
n−
·bE,
where:
a) Cat is at least one cationic species;
b) M is at least one species of metallic element;
c) X is at least one species selected from the group consisting of VO
4
, SO
4
, Cl, Br, I, H
2
O, HCOO and NO
2
;
d) E is at least one species selected from the group consisting of H
2
O, N
2
H
4
and organic solvents;
e) L is at least one species selected from the group consisting of H
2
O, O, NO, N
2
, acetyl acetone, pyridine, 2,2′-bipyridine, (H
2
N(CH
2
)
d
NH
2
) (d=2 or 3), RNH
2
and R
2
NH;
where if L=monodentate, then z=4 and where if L=bidentate, then z=2 or 4; and
a=2 or 3;
m=the number of cations and is in the range of about 0 to about 12;
n=the units of negative charge and is in the range of about 2 to about 6, except where m=0 in which case n=0 and
b=the number of solvent
eutral molecule(s)—E, in the lattice and is in the range of about 12 to about 30.
The prior art generally fails to provide an as simple as desired approach for the selectable synthesis of materials such as composed of well-defined metal oxide clusters.
The invention further comprehends a mixed-metal oxide-based solid which includes a linked array of a plurality of vanadium oxide building blocks wherein a vanadium and oxygen shell cluster encapsulates a central X unit, where X is at least one species selected from the group consisting of VO
4
, SO
4
, Cl, Br, I, H
2
O, HCOO and NO
2
.
The invention still further comprehends a method of making a mixed-metal oxide-based solid. In accordance with one embodiment, such a method includes the step of forming a linked array of metal and oxygen shell clusters each encapsulating a central X unit where X is at least one species selected from the group consisting of VO
4
, SO
4
, Cl, Br, I, H
2
O, HCOO and NO
2
.
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patent: 3956187 (1976-05-01), Betz
patent: 4454244 (1984-06-01), Woltermann
patent: 4619822 (1986-10-01), Hammou et al.
patent: 4816243 (1989-03-01), Guttmann et al.
patent: 5380692 (1995-01-01), Nakatsuji et al.
patent: 5578282 (1996-11-01), O'Young et al.
patent: 5637545 (1997-06-01), Lewis
patent: 5702674 (1997-12-01), O'Young et al.
Dunn Tom
Illinois Institute of Technology
Nguyen Cam N.
Pauley Petersen Kinne & Fejer
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