JPH05178612A - Oxidation of reduced polyoxoanion compound - Google Patents

Abstract

PURPOSE:To provide an oxidizing method of a reduced polyoxoanion compound using a catalyst. CONSTITUTION:In the oxidizing method of the reduced polyoxoanion compound in liquid phase, a metallic compound containing at least one or more metals selected from among lanthanum, zinc, bismuth, antimony, titanium, indium, samarium, cerium, zirconium, tantalum, vanadium, neodymium, gallium, nickel and niobium is used as a catalyst.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for oxidizing a reduced polyoxoanion compound with a catalyst.

[0002]

2. Description of the Related Art Polyoxoanion compounds are extremely important compounds as industrial catalysts in the chemical industry.

Generally, polyoxoanion compounds are strong oxidizing agents, and it is known that many of their redox reactions are reversible. For example, G.I. A. Tsig
dinos et al. (Topp. Curr. Chem., 7
6, 1 (1978)) reported that the redox reaction was reversible from cyclic voltammetry measurement of a heteropolyoxoanion composed of phosphorus, molybdenum and the like. Further, in this redox reaction, it is known that the reduced polyoxoanion compound is reversibly oxidized by an oxidant, particularly oxygen, in the solution.

For example, K. I. Matveev et al. (Ki
net. Katal. , 18,862 (1977)),
, P. Argitis et al. (Inorg. Chem.,
25, 4386 (1986)) report that a reduced heteropolyoxoanion consisting of phosphorus, molybdenum and vanadium is reversibly oxidized by oxygen. In addition, E. Papaconstantinou
(J. Chem. Soc. Chem. Commun.,
12 (1982)) report that a reduced heteropolyoxoanion consisting of phosphorus and molybdenum is reversibly oxidized by oxygen.

[0005]

However, the above-cited reference (Inorg. Chem., 25, 4386 (1
986), page 4388, left column, lines 49 to 51, J. C
hem. Soc. Chem. Commun. , 12 (1
982), page 13, right column, lines 19-30), and
C. L. Hill et al. (J. Am. Chem. So
c. , 107, 5148 (1985), page 5152, left column, lines 14 to 22) and the like, the oxidation reaction of the reduced polyoxoanion compound has a slow reaction rate and does not proceed smoothly. There is a problem. Therefore, for example, in a process using a polyoxoanion compound as a catalyst and the like, it has been desired to develop a method for smoothly oxidizing a reduced polyoxoanion compound with oxygen in a liquid phase.

[0006]

[Means for Solving the Problems] In view of the current situation,
The present inventors have made detailed studies on the oxidation reaction of the reduced polyoxoanion compound. As a result, surprisingly, the inventors have found the novel fact that the oxidation reaction of the reduced polyoxoanion compound proceeds more smoothly when a certain metal compound is used as a catalyst, and completed the present invention.

That is, according to the present invention, in a method of oxidizing a reduced polyoxoanion compound with oxygen in a liquid phase, lanthanum, zinc, bismuth, antimony, titanium, indium, samarium, and cerium are used as catalysts.
The present invention relates to a method for oxidizing a reduced polyoxoanion compound, which comprises using a metal compound containing at least one metal selected from zirconium, tantalum, vanadium, neodymium, gallium, nickel and niobium.

The present invention will be described in more detail below.

In the present invention, the polyoxoanion compound is, for example, M. T. Heterop by Pope
ol y and Isopoly Oxometala
As described in tes, it refers to those containing a polyoxoanion and one kind or two or more kinds of cations (counter cations).

The polyoxoanion constituting the polyoxoanion compound is represented by the following general formula (1) (hereinafter abbreviated as formula (1)). _{[X x L a M b N} c O z] -m ··· (1) where, X is P, B, Si, As, Ge, Se, T
showing an element selected from e, I, Co, Mn, and Cu,
L, M, and N are Mo, W, V, Nb, Ta, Re
From the above, and O represents an oxygen element. In general, the polyoxoanion is composed of an isopolyoxoanion produced by condensation of oxygen acids of the transition metals L, M, and N in formula (1) and an oxygen acid of the transition metals L, M, and N with the heteroatom X as the center. And a heteropolyoxoanion generated by condensation of oxygen by a condensed acid group sharing oxygen with each other. In addition, as the polyoxoanion, a single metal component type in which all L, M and N elements are the same and a mixed coordination type in which two or more different L, M and N elements are different are known. There is. x is 0 in the isopolyoxoanion, and x is a natural number in the heteropolyoxoanion. m represents the valence of the polyoxoanion. a, b, c, z, and m are positive integers, and a + b + c is 2 or more. Further, the heteropolyoxoanion having the hetero atom X at the center is characterized by its structure. For example, in the formula (1), x =
1, a + b + c = 12, z = 40 has three MOs
₆ octahedrons (M = Mo, W, V, etc.) share edges and M ₃ O
₁₃ form four of these one heteroatom X (X =
It is known as having a so-called "Keggin structure" that surrounds P, Si, etc.). Further, in the formula (1), x = 2, a + b + c = 18, and z = 62 are known as having a so-called “Dawson structure” in which the above M ₃ O ₁₃ 6 surrounds two heteroatoms X. Has been.

Among the polyoxoanions, examples of the isopolyoxoanion in which x = 0 in the formula (1) include, for example, [Mo ₇ O ₂₄ ] ⁶⁻ , [W ₁₀ O ₃₂ ] ^4- [Mo ₄ V _{8 ^{O 40] 8-, [Mo 3}} V 3 O 19] 5- [Mo 6 V 2 O 26] 6-, [Mo 6 V 6 O 36] 6- [W 7 Mo 3 V 2 O 36] 2-, [Mo ₈ V ₄ O ₃₆ ]
^4- etc. can be mentioned.

Among the polyoxoanions, in the formula (1), x is represented as a heteropolyoxoanion.
= 1, for example, [SiMo ₁₂ O ₄₀ ] ⁴⁻ ,
[SiMo ₈ W ₄ O ₄₀ ] ^4- , [SiW ₁₂ O ₄₀ ]
^4- , [PMo ₁₂ O ₄₀ ] ^3- , [PMo ₄ W ₈ O
₄₀ ] ³⁻ , [PMo ₆ W ₆ O ₄₀ ] ³⁻ , [PMo ₈
W ₄ O ₄₀ ] ³⁻ , [PMo ₆ V ₆ O ₄₀ ] ⁹⁻ , [P
^{_{Mo 8 V 4 O 40] 7-}} , [PMo 9 V
₃ O ₄₀ ] ⁶⁻ , [PMo ₁₀ V ₂ O ₄₀ ] ⁵⁻ , [P
Mo ₁₁ VO ₄₀ ] ^4- , [PW ₁₂ O ₄₀ ] ^3- ,
[PW ₁₁ VO ₄₀ ] ^4- , [PW ₁₀ V ₂ O ₄₀ ]
^5- , [GeMo ₁₂ O ₄₀ ] ^4- , [GeMo ₈ W ₄
O ₄₀ ] ⁴⁻ , etc. When x = 2, for example, [P ₂ Mo
₁₈ O ₆₂ ] ⁶⁻ , [P ₂ W ₁₈ O ₆₂ ] ⁶⁻ , [P ₂
Mo ₂ W ₁₅ VO ₆₂ ] ⁷⁻ , [P ₂ Mo ₅ W ₁₂ VO
₆₂ ] ⁷⁻ , [As ₂ W ₁₈ O ₆₂ ] ⁶⁻ , and the like.

In the present invention, the polyoxoanion may be either an isopolyoxoanion or a heteropolyoxoanion, but a heteropolyoxoanion stable in a reversible redox reaction is more preferable. In the formula (1), X and L, M, and N may be elements independently selected from the above-mentioned elements, and L,
Even if the elements of M and N are all the same 2
More than one species may be used, but X is preferably P, Si, and elements selected from Mo, W, and V as L, M, and N.

In the present invention, the polyoxoanion may be of the above-mentioned single metal component type or mixed coordination type. Further, the polyoxoanion has various structures such as the heteropolyoxoanion is known to have various structures such as Keggin structure and Dawson structure. It does not matter even if it has a different structure. In general, polyoxoanions are often known to be in dissociation equilibrium with polyoxoanions having a plurality of different compositions and structures in a solution. It may be in a dissociation equilibrium state of polyoxoanions having a plurality of different compositions and structures.

On the other hand, many cation species are known as counter cations for polyoxoanion compounds. For example, H ⁺ , various metal ions, for example, L
Alkali metal ions such as i ⁺ , Na ⁺ and K ⁺ , Ca
Alkaline earth metal ions such as ²⁺ and Mg ²⁺ , and nonmetallic cations such as onium such as ammonium ion and alkylammonium ion (secondary to quaternary ammonium ion) are known. In the present invention,
These counter cations may be one kind selected from these counter cations, or two or more kinds.

In general, polyoxoanion compounds often have water of crystallization.
The polyoxoanion compound may contain water of crystallization.

In the present invention, the reduced polyoxoanion compound is a reduced polyoxoanion compound obtained by reducing the polyoxoanion compound. It is known that the reaction of reducing a polyoxoanion compound is generally a reaction of reducing a polyoxoanion to generate a reduced polyoxoanion. Therefore, the reduced polyoxoanion compound includes the reduced polyoxoanion and the counter cation. The reduced polyoxoanion is represented by the following general formula (2) (hereinafter abbreviated as formula (2)). _{[X x L a M b N} c O z] -m-n ··· (2) wherein, X, L, M, N , O , and, x, a, b, c ,
z and m represent the same element or number as in formula (1). Further, n represents the number of reducing electrons of the reduced polyoxoanion, and usually n is 0 <n ≦ 6.

The reduced polyoxoanion has 1, 2, 3, 4, 5, 6 electrons corresponding to the values of n = 1, 2, 3, 4, 5, 6 in the formula (2), respectively. Represents a reduced polyoxoanion. Examples of these reduced polyoxoanions include those obtained by reducing the aforementioned isopolyoxoanion and those obtained by reducing the heteropolyoxoanion.

In the present invention, the reduced electron number n of the reduced polyoxoanion is not necessarily a positive integer. This is because, in a mixture of reduced polyoxoanions having different reduction electron numbers of n = 1 to 6, n may not be an apparent integer. Further, the reduced polyoxoanion and the non-reduced polyoxoanion may coexist. Moreover, even if the electrons generated in the reduced polyoxoanion and present in the reduced polyoxoanion are localized in the specific metal constituting the polyoxoanion, the electrons are distributed in the entire polyoxoanion. It does not matter which is delocalized. Further, the reduced polyoxoanion may be in a dissociation equilibrium state of the reduced polyoxoanion having a plurality of different compositions or structures, where the reduced polyoxoanion has a different number of reducing electrons. It may be dissociated into a reduced polyoxoanion or a non-reduced polyoxoanion.

On the other hand, in the case of preparing a reduced polyoxoanion compound by reducing the polyoxoanion compound, a part of the reducing agent described later becomes a counter cation of the reduced polyoxoanion compound. In the present invention, a part of the reducing agent may be a counter cation or may be replaced with a counter cation of the polyoxoanion compound before undergoing reduction.

In the present invention, the reduced polyoxoanion compound can be prepared by reducing the polyoxoanion compound by a known method. For example, hydrogen or organic compounds such as hydrazine, oxalic acid, citric acid, ascorbic acid, aldehydes, alcohols, ketones, sodium borohydride, ferrous sulfate, cuprous chloride, stannous chloride, etc. A polyoxoanion compound reduced by a method of reducing in a liquid phase with a reducing agent such as a metal salt, a metal such as copper or iron, or a method of reducing in a liquid phase by giving an electron by an electrochemical method Can be obtained. In the present invention, the reduced polyoxoanion compound may be reduced by any of these methods. In these methods, a reducing polyoxoanion compound having a desired number of reducing electrons can be obtained by changing the reducing conditions, the amount of the reducing agent and the like.

In addition, the various reduced polyoxoanion compounds include those having water of crystallization.

The present invention oxidizes the thus-reduced reduced polyoxoanionic compound in the presence of the catalyst of the present invention. In the present invention, the above-mentioned oxidation of the reduced polyoxoanion compound means that the reduced electron number of the reduced polyoxoanion compound decreases. Therefore, the reduced polyoxoanion compound is oxidized, and the reduced polyoxoanion compound in a more oxidized state, or the original polyoxoanion compound, and a mixed equilibrium state thereof may be used. ..

In the present invention, as a catalyst in the reaction for oxidizing the reduced polyoxoanion compound,
A metal compound containing at least one metal selected from lanthanum, zinc, bismuth, antimony, titanium, indium, samarium, cerium, zirconium, tantalum, vanadium, neodymium, gallium, nickel and niobium can be used. As this catalyst, at least 1
There is no particular limitation as long as it contains one kind of the metal compound.
Examples of such metal compounds include inorganic salts such as hydrochlorides, nitrates, sulfates, carbonates and phosphates of the above metals, organic salts such as acetates, complex salts such as acetylacetonato complex, carbonyl complex and ammine complex. And the like. These inorganic salts, organic salts, complex salts and the like may be hydrates.
Further, as the metal compound, the above metal, metal oxide, or the like can be used. Further, these metal compounds may be carried on a carrier or the like, for example, silica, alumina, activated carbon, or other known carriers, without any particular problem. In addition, these metal compounds may be used alone or in combination of two or more kinds as a mixture or a composite compound.

The abundance ratio of the metal compound as the catalyst used in the method of the present invention and the reduced polyoxoanion compound is not particularly limited, but is usually per mol of the reduced polyoxoanion compound. , Metal compound 0.0001 to 50 mol, preferably 0.000
It is 5 to 20 mol, more preferably about 0.002 to 5 mol.

The oxidation reaction of the reduced polyoxoanion compound in the present invention can be carried out in a solution in which they are dissolved. Any solvent can be used as this solvent as long as it can dissolve the reduced polyoxoanion compound. Usually, water can be used, and the solvent can be used in an aqueous solution. In the present invention, the water solvent may be used alone, or acetonitrile, γ-butyrolactone, dimethylformamide, methyl ethyl ketone, sulfolane, ethanol, tert-butyl alcohol, dioxane,
A polar solvent such as acetic acid may be mixed. Further, if necessary, a mineral acid such as sulfuric acid, nitric acid, phosphoric acid or hydrochloric acid may be appropriately added.

The concentration of the reduced polyoxoanion compound is not particularly limited as long as it becomes a solution under the oxidation reaction condition, but is usually 0.01% by weight to 80% by weight.
The oxidation reaction can be carried out at a concentration of about wt% (saturated solution).

In the present invention, the oxidation reaction of the reduced polyoxoanion compound is carried out by allowing oxygen to coexist as an oxidizing agent. There are no particular restrictions on the oxygen that can be used, but normally pure oxygen or air diluted with an inert gas such as nitrogen can be used. It is also possible to coexist with an oxidizing agent or the like in which oxygen has already been activated such as organic peracid and hydrogen peroxide. The abundance ratio of oxygen and the reduced polyoxoanion compound is not particularly limited, but is usually an excess of 2 mol or more in molar ratio with respect to the reduced polyoxoanion compound in the present oxidation reaction. A quantity of oxygen can be present. Since oxygen is consumed in the oxidation reaction, it is possible to appropriately supplement oxygen to carry out the reaction. In the method of supplementing oxygen, the abundance ratio does not have to be an excessive amount. The reaction temperature in the present invention is not particularly limited, but is usually 0 to 200 ° C, preferably 30 to 150 ° C. Further, the reaction pressure is from normal pressure to
It can be appropriately selected within a wide range of high pressure,
It is in the range of atmospheric pressure to about 100 Kg / cm ² . At this time, the partial pressure of oxygen can be appropriately selected within the range of atmospheric pressure to about 50 Kg / cm ² .

In the method of the present invention, the reaction is a batch system,
Any method such as a semi-batch method or a continuous method may be used. Usually, normal pressure or pressure batch method, normal pressure or pressure semi-batch method, or normal pressure or continuous pressure A method etc. can be adopted.

The reaction time in the present invention depends on the kind of reduced polyoxoanion compound, the amount of catalyst, the reaction pressure,
It cannot be unambiguously defined because it varies depending on the reaction conditions such as reaction temperature and the reaction method, etc., but usually, in the case of a batch reaction, it takes between several minutes and several hours, preferably between 1 minute and 24 hours. The reaction can be carried out, and in the case of a continuous reaction, the contact time is 0.1 to 10
Time is fine.

[0031]

EXAMPLES The present invention will be specifically described below with reference to examples, but it goes without saying that the present description is not limited to these examples.

In the following Examples and Comparative Examples, the degree of progress of the oxidation reaction is represented by the oxidation rate of the reduced polyoxoanion compound shown below. The oxidation rate of the reduced polyoxoanion compound is calculated by the following formula (3). Oxidation rate of reduced polyoxoanion compound (%) = (A−B) × 100 / A (3) where A and B are A = reduced polyoxoanion compound before oxidation reaction Number of reducing electrons of compound B = number of reducing electrons of reduced polyoxoanion compound after oxidation reaction However, polyoxoanion that has been completely oxidized by reduction reaction and has not undergone reduction When it becomes a system compound, B = 0. .

In the above formula (3), the oxidation rate (%) of the reduced polyoxoanion compound is decreased by the ratio of the number of reduced electrons of the reduced polyoxoanion compound being oxidized. The closer the value is to 100%, the more the oxidation reaction proceeds.

The number of reducing electrons is determined by KM of the reduced polyoxoanion compound before and after the reaction.
It was performed by titration with an nO ₄ solution or ultraviolet-visible-near infrared absorption spectrum measurement.

Example 1 In a 500 ml four-necked flask equipped with a dropping funnel, a reflux condenser, a 100 ° C. thermometer, and a magnetic stirrer, H ₃ PMo ₆ W ₆ O ₄₀ was added as a polyoxoanion compound.
・ 30H ₂ O (manufactured by Nippon Inorganic Chemical Co., Ltd.) 144.66 g (5
0 mmol) and 100 ml of water were added to dissolve the polyoxoanion compound. H ₂ NNH _{2 in} 50 ml of water
· _H was dissolved 2 O 1.25g (25mmol) was placed in a dropping funnel. This was added dropwise to the above polyoxoanion compound aqueous solution over 30 minutes under N ₂ atmosphere while stirring. Further, the polyoxoanion compound was reduced by heating and stirring at 40 ° C. for 3 hours and at 60 ° C. for 1 hour. The solution after the reaction was dark blue. The reaction solution was cooled to room temperature and then diluted with water to prepare a reduced polyoxoanion compound as a 0.2 mol / l aqueous solution. From the titration with the KMnO ₄ solution, the number of reducing electrons of the obtained reduced polyoxoanion compound was 2 electrons. In this way, 0.2 mol / l
Two-electron reduced polyoxoanion compound H ₅ P
A Mo ₆ W ₆ O ₄₀ aqueous solution was obtained. 0.2 mol of the above
/ L Two-electron reduced polyoxoanion compound
30 ml of H ₅ PMo ₆ W ₆ O ₄₀ aqueous solution (two-electron reduced polyoxoanion compound H ₅ PMo ₆ W
₆ O ₄₀ 6.0 mmol containing), and lanthanum nitrate hexahydrate as catalyst _{(La (NO 3) 3 ·} 6H
₂ O) 0.0520 g (0.12 mmol) was charged into a 100 ml autoclave with a stirring blade made of Teflon, oxygen 4 kg / cm ² (absolute pressure) was injected, and a stirring speed of 800
The mixture was reacted at 60 ° C for 30 minutes while stirring at rpm. In the reaction, oxygen was supplied and supplemented so that the pressure during the reaction became constant. After the reaction was completed, the reaction solution was allowed to cool, and the reaction solution was KMn.
When titrated with an O ₄ solution, the oxidation rate of the polyoxoanion compound reduced by this reaction was 18.1%.

That is, the polyoxoanion compound H ₅ PMo ₆ W ₆ O reduced by two electrons by this reaction
The reduced electrons of ₄₀ are 18.1% gone.

Example 2 In Example 1, 0.0194 g of zinc sulfate (ZnSO ₄ ) was used as a catalyst instead of lanthanum nitrate hexahydrate in the oxidation of the reduced polyoxoanion compound.
The same reaction as in Example 1 was performed except that (0.12 mmol) was used. As a result, the oxidation rate of the reduced polyoxoanion compound was 13.5%.

Comparative Example 1 The same reaction as in Example 1 was carried out except that lanthanum nitrate hexahydrate was not added in the oxidation of the reduced polyoxoanion compound.
As a result, the oxidation rate of the reduced polyoxoanion compound was 1.8%.

Example 3 In Example 1, bismuth sulfate (Bi ₂ (SO ₄ ) ₃ ) 0.084 was used instead of lanthanum nitrate hexahydrate in the oxidation of the reduced polyoxoanion compound.
Example 1 except that 7 g (0.12 mmol) was used
Reaction exactly the same as was performed. As a result, the oxidation rate of the reduced polyoxoanion compound was 11.4%.

Example 4 In Example 1, 0.0274 g of antimony trichloride (SbCl ₃ ) was used in place of lanthanum nitrate hexahydrate in the oxidation of the reduced polyoxoanion compound.
The same reaction as in Example 1 was performed except that (0.12 mmol) was used. As a result, the oxidation rate of the reduced polyoxoanion compound was 10.8%.

[0041] In Example 5 Example 1, in place of lanthanum nitrate hexahydrate in the oxidation of the reduced polyoxometalate anion compound, titanium sulfate tetrahydrate _{(Ti (SO 4) 2 ·} 4H 2
O) The same reaction as in Example 1 was performed except that 0.0374 g (0.12 mmol) was used. as a result,
The oxidation rate of the reduced polyoxoanion compound is 1
It was 0.6%.

Example 6 In Example 1, instead of lanthanum nitrate hexahydrate in the oxidation of the reduced polyoxoanion compound, indium sulfate nonahydrate (In ₂ (SO ₄ ) ₃
9H ₂ O) 0.0816 g (0.12 mmol) was used, and the same reaction as in Example 1 was performed. As a result, the oxidation rate of the reduced polyoxoanion compound was 10.1%.

[0043] In Example 7 Example 1, in place of lanthanum nitrate hexahydrate in the oxidation of the reduced polyoxometalate anionic compounds, samarium nitrate hexahydrate _{(Sm (NO 3) 3 ·} 6
H ₂ O) The reaction was performed in exactly the same manner as in Example 1 except that 0.0533 g (0.12 mmol) was used. As a result, the oxidation rate of the reduced polyoxoanion compound was 8.8%.

[0044] In Example 8 Example 1, in place of lanthanum nitrate hexahydrate in the oxidation of the reduced polyoxometalate anion compound, cerium nitrate hexahydrate _{(Ce (NO 3) 3 ·} 6H
₂ O) The same reaction as in Example 1 was performed except that 0.0521 g (0.12 mmol) was used. As a result, the oxidation rate of the reduced polyoxoanion compound was 8.6%.

Example 9 In Example 1, reduction polyoxoanion systemization
Instead of lanthanum nitrate hexahydrate in the oxidation of compounds
Zirconium oxide chloride octahydrate (ZrCl _TwoO
8H_TwoO) using 0.0387 g (0.12 mmol)
Except for the above, the same reaction as in Example 1 was performed. That
As a result, the oxidation rate of the reduced polyoxoanion compound
Was 8.1%.

Example 10 In Example 1, instead of lanthanum nitrate hexahydrate in the oxidation of the reduced polyoxoanion compound, tantalum chloride (TaCl ₅ ) 0.0430 g (0.
The same reaction as in Example 1 was performed except that 12 mmol) was used. As a result, the oxidation rate of the reduced polyoxoanion compound was 5.5%. In Example 11 Example 1, in place of lanthanum nitrate hexahydrate in the oxidation of the reduced polyoxometalate anion compound, vanadyl sulfate _(VOSO 4) _{0.0195g (0.}
The same reaction as in Example 1 was performed except that 12 mmol) was used. As a result, the oxidation rate of the reduced polyoxoanion compound was 4.9%.

[0047] In Example 12 Example 1, in place of lanthanum nitrate hexahydrate in the oxidation of the reduced polyoxometalate anionic compounds, neodymium nitrate hexahydrate _{(Nd (NO 3) 3 ·} 6H
₂ O) The reaction was carried out in exactly the same manner as in Example 1 except that 0.0526 g (0.12 mmol) was used. As a result, the oxidation rate of the reduced polyoxoanion compound was 4.5%.

[0048] In Example 13 Example 1, in place of lanthanum nitrate 6-hydrate in the oxidation of the reduced polyoxometalate anionic compounds, gallium nitrate octahydrate _{(Ga (NO 3) 3 ·} 8H
₂ O) The same reaction as in Example 1 was performed except that 0.0460 g (0.12 mmol) was used. As a result, the oxidation rate of the reduced polyoxoanion compound was 4.7%.

[0049] In Example 14 Example 1, in place of lanthanum nitrate hexahydrate in the oxidation of the reduced polyoxometalate anionic compounds, nickel sulfate hexahydrate _(NiSO 4 · _6H 2 O)
The same reaction as in Example 1 was performed except that 0.0315 g (0.12 mmol) was used. As a result, the oxidation rate of the reduced polyoxoanion compound was 4.0%.
Met.

Example 15 In Example 1, instead of lanthanum nitrate hexahydrate in the oxidation of the reduced polyoxoanionic compound, niobium chloride (NbCl ₅ ) 0.0324 g (0.1
The same reaction as in Example 1 was performed except that 2 mmol) was used. As a result, the oxidation rate of the reduced polyoxoanion compound was 3.4%.

Example 16 The same reaction as in Example 1 was carried out except that the reaction temperature was set to 40 ° C. in the oxidation of the reduced polyoxoanion compound. As a result, the oxidation rate of the reduced polyoxoanion compound was 5.8%.

Example 17 The same reaction as in Example 2 was carried out except that the reaction temperature was set to 40 ° C. in the oxidation of the reduced polyoxoanion compound. As a result, the reduced polyoxoanion compound had an oxidation rate of 3.8%.

Example 18 The same reaction as in Example 1 was carried out except that the reaction temperature was 100 ° C. in the oxidation of the reduced polyoxoanion compound. As a result, the oxidation rate of the reduced polyoxoanion compound was 28.9.
%Met.

Example 19 The same reaction as in Example 2 was carried out except that the reaction temperature was 100 ° C. in the oxidation of the reduced polyoxoanion compound. As a result, the oxidation rate of the reduced polyoxoanion compound was 21.8.
%Met.

Example 20 In Example 1, the amount of lanthanum nitrate hexahydrate in the oxidation of the reduced polyoxoanionic compound was changed to
The same reaction as in Example 1 was performed except that the amount was 0.013 g (0.03 mmol). As a result, the oxidation rate of the reduced polyoxoanion compound was 10.1%.

Example 21 In a 500 ml four-necked flask equipped with a dropping funnel, a reflux condenser, a 100 ° C. thermometer, and a magnetic stirrer, H ₃ PMo ₁₂ O ₄₀ was added as a polyoxoanion compound.
・ 29H ₂ O (Nippon Inorganic Chemicals Co., Ltd.) 11.74 g (5 m
mol) and 100 ml of water were added to dissolve the polyoxoanion compound. H ₂ NNH ₂ · H in 50 ml of water
0.250 g (5 mmol) of ₂ O was dissolved and placed in a dropping funnel. This was added dropwise to the above polyoxoanion compound aqueous solution over 30 minutes under N ₂ atmosphere while stirring. Furthermore, the polyoxoanion compound was reduced by heating and stirring at 40 ° C. for 3 hours and at 60 ° C. for 3 hours.
The solution after the reaction was dark blue. After the reaction solution was cooled to room temperature, water and H ₃ PO ₄ were added to prepare a reduced polyoxoanion compound as a 0.02 mol / l aqueous solution (containing 1 wt% H ₃ PO ₄ ). .. K
From the titration with the MnO ₄ solution, the number of reducing electrons of the obtained reduced polyoxoanion compound was 4 electrons. In this way, 0.02 mol / l 4 electron-reduced polyoxoanion compound H ₇ PMo ₁₂ O
₄₀ aqueous solution (containing 1 wt% H ₃ PO ₄ ) was obtained.

The above-mentioned 0.02 mol / l 4 electron-reduced polyoxoanion compound H ₇ PMo ₁₂ O ₄₀
30 ml of an aqueous solution (containing 1 wt% H ₃ PO ₄ ) (4-electron reduced polyoxoanion compound H ₇ PMo)
₁₂ O _{40 (} 0.60 mmol content) and lanthanum nitrate hexahydrate 0.0520 g (0.1
(2 mmol) was charged into a 100 ml autoclave equipped with a Teflon stirring blade, oxygen 4 kg / cm ² (absolute pressure) was injected, and the reaction was carried out at 60 ° C. for 30 minutes while stirring at 800 rpm. In the reaction, oxygen was supplied and supplemented so that the pressure during the reaction became constant. After completion of the reaction, the reaction solution was allowed to cool, and then the reaction solution was titrated with a KMnO ₄ solution. As a result, the oxidation rate of the polyoxoanion compound reduced by this reaction was 23.6%.

That is, the polyoxoanion compound H ₇ PMo ₁₂ O ₄₀ which has been reduced by four electrons by this reaction
This means that the reduced electrons of are no more than 23.6%.

Example 22 In a 500 ml four-necked flask equipped with a dropping funnel, a reflux condenser, a 100 ° C. thermometer and a magnetic stirrer, H ₅ PMo ₁₀ V ₂ O ₄₀ was added as a polyoxoanion compound.
・ 31H ₂ O (manufactured by Nippon Inorganic Chemical Co., Ltd.) 114.79 g (5
0 mmol) and 100 ml of water were added to dissolve the polyoxoanion compound. H ₂ NNH ₂ · in 50 ml of water
1.25 g (2.5 mmol) of H ₂ O was dissolved and placed in a dropping funnel. This was added dropwise to the above polyoxoanion compound solution under N ₂ atmosphere over 30 minutes while stirring. Furthermore, the polyoxoanion compound was reduced by heating and stirring at 40 ° C. for 3 hours and at 60 ° C. for 3 hours.
The solution after the reaction was deep blue-green. The reaction solution was cooled to room temperature and then diluted with water to prepare a reduced polyoxoanion compound as a 0.2 mol / l aqueous solution.

From the visible-near infrared absorption spectrum measurement, the number of reducing electrons of the obtained reduced polyoxoanion compound was 2 electrons. In this way, 0.2 mol
/ L Two-electron reduced polyoxoanion compound H
₇ PMo ₁₀ V ₂ O ₄₀ aqueous solution was obtained.

The above-mentioned 0.2 mol / l 2 electron-reduced polyoxoanion compound H ₇ PMo ₁₀ V ₂ O
₄₀ ml of an aqueous solution of 30 ml (two-electron reduced polyoxoanion compound H ₇ PMo ₁₀ V ₂ O ₄₀ 6.0
(containing mmol) and lanthanum nitrate-6 as a catalyst
Hydrate 0.0520 g (0.12 mmol) was charged into a 100 ml autoclave equipped with a Teflon stirring blade,
Oxygen 4 kg / cm ² (absolute pressure) was press-fitted, stirring speed 80
The mixture was reacted at 60 ° C for 30 minutes while stirring at 0 rpm. In the reaction, oxygen was supplied and supplemented so that the pressure during the reaction became constant. After completion of the reaction, the reaction solution was allowed to cool and then the reaction solution was subjected to visible-near infrared absorption spectrum measurement. As a result, the oxidation rate of the polyoxoanion compound reduced by this reaction was 1
It was 6.6%.

That is, a polyoxoanion compound H ₇ PMo ₁₀ V ₂ O which has been reduced by two electrons by this reaction
The reduced electrons of ₄₀ are 16.6% gone.

Example 23 The same reaction as in Example 22 was carried out except that 0.0194 g (0.12 mmol) of zinc sulfate was used instead of lanthanum nitrate hexahydrate. .. As a result, the oxidation rate of the reduced polyoxoanion compound was 18.1%.

[0064]

INDUSTRIAL APPLICABILITY In the present invention, a reduced polyoxoanion compound can be smoothly oxidized by oxygen by using a metal compound as a catalyst. The oxidation of a reduced polyoxoanion compound, which has been a problem in the past, can be catalytically promoted by the present invention, and the present invention is directed to a process using a polyoxoanion compound as a catalyst. It has extremely high utility value industrially.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical display location B01J 27/25 M 7038-4G C01G 39/00 Z 8516-4G 41/00 A 8516-4G

Claims (1)

[Claims] 1. A method for oxygen-oxidizing a reduced polyoxoanion compound in a liquid phase, wherein lanthanum, zinc, bismuth, antimony, titanium, indium, samarium, cerium, zirconium, tantalum are used as catalysts.
A method for oxidizing a reduced polyoxoanion compound, which comprises using a metal compound containing at least one metal selected from vanadium, neodymium, gallium, nickel and niobium.