Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Organic compound containing
Reexamination Certificate
2000-06-27
2002-12-17
Bell, Mark L. (Department: 1755)
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Organic compound containing
C502S162000, C502S209000, C502S353000
Reexamination Certificate
active
06495486
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to an intercalation compound comprising vanadium, phosphorus and oxygen as primary components with monohydric alcohol being intercalated between layers of the compound and to a vanadium phosphorus mixed oxide as well as to processes for preparing the same.
DESCRIPTION OF THE PRIOR ART
As a layered compound comprising vanadium, phosphorus and oxygen as primary components, vanadyl phosphate, vanadyl hydrogen phosphate hemihydrate or the like is known. Here, vanadyl hydrogen phosphate hemihydrate, VOHOP
4
.0.5H
2
O, is well known as a precursor for divanadyl pyrophosphate, [(VO)
2
P
2
O
7
], which is used as a catalyst for the preparation of maleic anhydride by oxidizing butane.
It is known that an organic compound is intercalated between layers of these layered compounds to give a substance with a widened space between the layers. For example, a substance intercalated with pyridine or pyrrole is disclosed in
Inorg. Chem.
21, 3820 (1982) and
Chem. Lett.
31 (1993).
U.S. Pat. No. 4,418,003 disclosed a process for the manufacture of a phosphorus vanadium catalyst suitable for use in the manufacture of maleic anhydride from butane, which process comprises reacting P
2
O
3
in an aliphatic alcohol having 1 to 8 carbon atoms to produce mixed phosphate esters and reacting a vanadium compound with an inorganic acid in the aliphatic alcohol to prepare acidified alcohol and a vanadium ester, and using these to produce a vanadium phosphorus oxide catalyst which is dissolved in the acidified alcohol. The inter-layer space of the catalyst produced is 8.75 Å, which is larger than that of vanadyl hydrogen phosphate hemihydrate, 5.4 Å. This suggest that methanol is intercalated between the layers.
Vanadium-phosphorus mixed oxide is widely known as a catalyst or as a precursor thereof for the manufacture of maleic anhydride by oxidizing butane. Generally, vanadium-phosphorus mixed oxide is prepared by calcining vanadyl phosphate or vanadyl hydrogen phosphate hemihydrate, comprising vanadium, phosphorus and oxygen as primary components, in a nitrogen atmosphere or a reactive atmosphere comprising butane, nitrogen and oxygen at 350° C. to 700° C. The vanadium-phosphorus mixed oxide thus obtained has a relatively small surface area of from 10 to 50 m
2
/g.
To prepare a catalyst of higher activity, some studies have been made to increase a surface area of vanadium-phosphorus mixed oxide.
Catal. Today
16, 113 (1993) describes a method where vanadyl hydrogen phosphate hemihydrate is mixed with water or lower alcohol and then calcined to obtain a larger surface area of the calcined product. However, the surface area of the resultant calcined product is at most about 64 m
2
/g.
Appl. Catal.
154, 103 (1997) describes a method where vanadyl hydrogen phosphate hemihydrate is crashed to powder with a ball mill to obtain a larger surface area of the calcined product. However, the surface area of the resultant calcined product is at most about 46 m
2
/g. In either method, the surface area of the resultant calcined product is not satisfactory for a catalyst for preparing maleic anhydride.
For producing a vanadium-phosphorus mixed oxide having meso-micropores,
Chem. Mater.,
7,1429 (1995) discloses a method of synthesizing a meso structure material having a hexagonal structure comprising vanadium and phosphorus by using alkyltrimethylammonium chloride as a template agent, wherein alkyl group has 12 to 16 carbon atoms. It mentions nothing about a surface area of the vanadium-phosphorus mixed oxide.
Japanese Patent Application Laid-open H8-259208 discloses an intercalation compound and a method of preparing the same, in which compound diols are intercalated between layers of a layered compound comprising vanadium, phosphorus and oxygen as primary components. There, monohydric alcohols are not intercalated. As shown in its Comparative Example, isobutyl alcohol, which is a monohydric alcohol, cannot be intercalated between layers of the layered compound comprising vanadium, phosphorus and oxygen as primary components in that method.
WO 98/15353 discloses an intercalation compound and a method of preparing the same, in which compound an aliphatic primary monohydric alcohol is intercalated between layers of a layered compound comprising vanadium, phosphorus and oxygen as primary components. In the method, V
2
O
5
, P
2
O
5
and the aliphatic primary monohydric alcohol are reacted in atmospheric pressure. The method is to intercalate an aliphatic primary monohydric alcohol, and accordingly, nothing is described about intercalation of an alicyclic monohydric alcohol or an aromatic monohydric alcohol. In the Comparative Examples, it is mentioned that secondary alcohols and tertiary alcohols cannot be intercalated. Further, an extremely long time is required to intercalate aliphatic primary monohydric alcohol. For example, in Example 1, 455 hours were required for intercalating methanol. In order to intercalate a branched aliphatic primary monohydric alcohol, it is suggested that it is necessary to use a more concentrated phosphoric acid to increase a rate of the reaction. However, by the method, a compound with a sufficient amount of intercalated branched aliphatic primary monohydric alcohol was not obtained, judging from a small intensity of the X-ray diffraction pattern showing intercalation of the branched aliphatic primary monohydric alcohol.
PURPOSE OF THE INVENTION
The purpose of the present invention is to provide a novel intercalation compound in which an aliphatic secondary monohydric alcohol, an alicyclic monohydric alcohol, or an aromatic monohydric alcohol is intercalated between the layers of a compound comprising vanadium, phosphorus and oxygen as primary components.
Another purpose of the present invention is to provide a novel method for quickly and conveniently preparing an intercalation compound in which a monohydric alcohol is intercalated between a layered compound comprising vanadium, phosphorus and oxygen as primary components.
Still another purpose of the present invention is to provide a novel vanadium-phosphorus mixed oxide having a remarkably large surface area and a method of preparing the same.
SUMMARY OF THE INVENTION
The present inventors have made intensive researches for a method of intercalating various kinds of monohydric alcohols between layers of a layered compound comprising vanadium, phosphorus and oxygen as primary components. As a result, it has been found that by reacting vanadium oxide having a valence of vanadium in a range of at least 4 to less than 5, phosphorus pentoxide and monohydric alcohol in atmospheric pressure, or by reacting vanadium oxide having a valence of vanadium in a range of at least 4 to at most 5, phosphorus pentoxide and a monohydric alcohol under pressure, the monohydric alcohol can be intercalated between layers of the layered compound comprising vanadium, phosphorus and oxygen as primary components, which cannot be attained by the method described in JPA Laid-open H8-259208. Also it has been found that aliphatic secondary monohydric alcohols, alicyclic monohydric alcohols or aromatic monohydric alcohols as well as aliphatic primary monohydric alcohols can be intercalated quickly and conveniently between layers of the layered compound comprising vanadium, phosphorus and oxygen as primary components, which cannot be attained by the method described in WO 98/15353.
Thus, the present invention is (1) an intercalation compound in which monohydric alcohol is intercalated between layers of a layered compound comprising vanadium, phosphorus and oxygen as primary components, characterized in that the monohydric alcohol is aliphatic secondary monohydric alcohol, alicyclic monohydric alcohol, or aromatic monohydric alcohol.
Preferred embodiments of the present invention are as follows. (2) The intercalation compound described in (1) above, wherein the compound has a structure where a part or the whole of a moiety, POH, present in a layered compound, vanadyl hydrogen phosphate hemihydrate re
Kamiya Yuichi
Nishikawa Eiichiro
Bell Mark L.
Hailey Patricia L.
Pitney Hardin Kipp & Szuch LLP
Tonen Chemical Corporation
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