JP3203722B2 - Method for oxidizing reduced polyoxoanionic compounds - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for oxidizing a reduced polyoxoanionic compound using a catalyst.

[0002]

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

[0003] In general, polyoxoanionic compounds are known to be strong oxidants, and many of their redox reactions are reversible. For example, G. A. Tsig
dinos et al. (Topp. Curr. Chem., 7
6, 1 (1978)) report that the oxidation-reduction reaction is reversible from the measurement of cyclic voltammetry of a heteropolyoxoanion composed of phosphorus, molybdenum and the like. It is also known that in this redox reaction, the reduced polyoxoanionic compound is reversibly oxidized by an oxidizing agent, particularly oxygen, in the solution.

[0004] For example, K. I. Matveev et al. (Ki
net. Katal. , 18, 862 (1977)),
And P. Argitis et al. (Inorg. Chem.,
25, 4386 (1986)) report that reduced heteropolyoxoanions consisting of phosphorus, molybdenum and vanadium are reversibly oxidized by oxygen. Also, E.I. 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 document (Inorg. Chem., 25, 4386 (1)
986), page 4388, left column, lines 49-51; 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), p. 5152, left column, lines 14-22), etc., the oxidation reaction of the reduced polyoxoanion compound is slow and does not proceed smoothly. There is a problem. Therefore, for example, in a process using a polyoxoanion compound as a catalyst, it has been desired to develop a method for smoothly oxidizing a reduced polyoxoanion compound with oxygen in a liquid phase.

[0006]

In view of the above situation,
The present inventors have studied in detail the oxidation reaction of a reduced polyoxoanionic compound. As a result, they have unexpectedly found that the use of a certain metal compound as a catalyst allows the oxidation reaction of the reduced polyoxoanion compound to proceed more smoothly, and completed the present invention.

That is, the present invention relates to a method for oxidizing a reduced polyoxoanionic compound with oxygen in a liquid phase, wherein lanthanum, zinc, bismuth, antimony, titanium, indium, samarium, cerium,
The present invention relates to a method for oxidizing a reduced polyoxoanion compound, characterized by using a metal compound containing at least one metal selected from zirconium, tantalum, vanadium, neodymium, gallium, nickel and niobium.

Hereinafter, the present invention will be described in more detail.

In the present invention, the polyoxoanionic compound is, for example, M.P. T. Heterop by Pope
oly and Isopoly Oxmetalla
As described in tes, those containing a polyoxoanion and one or more 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
e, an element selected from I, Co, Mn, and Cu,
L, M and N are Mo, W, V, Nb, Ta, Re
And O represents an oxygen element. In general, the polyoxoanion is composed of an isopolyoxoanion formed by condensation of oxyacids of transition metals L, M, and N in Formula (1) and an oxyacid of transition metals L, M, and N centered on heteroatom X. And a heteropolyoxoanion which is formed by condensing a condensed acid group by sharing oxygen. In addition, polyoxoanions are known as a single metal component type in which the elements of L, M, and N are all the same, and a mixed coordination type having two or more different elements of L, M, and N. I have. x is 0 for an isopolyoxoanion, and x is a natural number for a 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. A heteropolyoxoanion having a heteroatom X at its center is characterized by its structure. For example, in the formula (1), x =
1, a + b + c = 12 and z = 40 have three MOs
₆ octahedrons (M = Mo, W, V, etc.) share edges and M ₃ O
₁₃ and these four form one heteroatom X (X =
P, Si, etc.) are known as having a so-called “Keggin structure”. In the formula (1), those having x = 2, a + b + c = 18 and z = 62 are known as having a so-called “Dawson structure” in which six M ₃ O ₁₃ surround two heteroatoms X. Have been.

Among the polyoxo anions, in the formula (1), as the isopolyoxo anion where x = 0, 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- and the} like.

Further, among the polyoxo anions, in the formula (1), the heteropolyoxo anion is represented by x
= 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 polyoxo anion may be an isopolyoxo anion or a heteropolyoxo anion, but a heteropolyoxo anion which is stable in a reversible oxidation-reduction reaction is more preferable. In the formula (1), X, and L, M, and N may be elements independently selected from the above-described elements.
Even if all the elements M and N are the same,
Although it may be more than one kind, X is preferably an element selected from P, Si, and L, M, and N selected from Mo, W, and V.

In the present invention, the polyoxo anion may be of the above-mentioned single metal component type or of the mixed coordination type. Furthermore, the polyoxoanion has various structures, for example, it is known that the heteropolyoxoanion has various structures such as a Keggin structure and a Dawson structure.However, in the present invention, what kind of polyoxoanion is There is no particular problem even if it has a simple structure. In general, it is known that polyoxo anions are often in a dissociation equilibrium state of polyoxo anions having a plurality of different compositions and structures in a solution, but in the present invention, polyoxo anions are dissolved in a solution. A plurality of different compositions and structures of polyoxoanions may be in a dissociation equilibrium state.

On the other hand, many cationic species are known as counter cations of polyoxoanionic compounds. For example, H ⁺ , various metal ions such as L
alkali metal ions such as i ⁺ , Na ⁺ , K ⁺ , and Ca
Known are alkaline earth metal ions such as ²⁺ and Mg ²⁺ , and nonmetallic cations such as onium such as ammonium ions and alkylammonium ions (secondary and quaternary ammonium ions). In the present invention,
These counter cations may be one type selected from these counter cations, or two or more types.

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

In the present invention, the reduced polyoxoanionic compound is a reduced polyoxoanionic compound obtained by reducing the above-mentioned polyoxoanionic compound. It is known that a reaction in which a polyoxoanion compound is reduced is a reaction in which a polyoxoanion is generally reduced to generate a reduced polyoxoanion. Therefore, the reduced polyoxoanion compound contains a reduced polyoxoanion and a counter cation. The reduced polyoxo anion 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 elements as in the formula (1) or numbers. N represents the number of reduced electrons of the reduced polyoxoanion, and usually, n is 0 <n ≦ 6.

In the formula (2), the reduced polyoxoanions correspond to the values of n = 1, 2, 3, 4, 5, and 6, respectively, and are 1, 2, 3, 4, 5, and 6 electrons, respectively. Represents a reduced polyoxoanion. Examples of these reduced polyoxo anions include those in which the above-mentioned isopolyoxo anions have been reduced and those in which the heteropolyoxo anions have been reduced.

In the present invention, the reduced electron number n of the reduced polyoxoanion does not necessarily have to be a positive integer. This is because in a mixture of reduced polyoxoanions having different numbers of reducing electrons in which n = 1 to 6, n may not be an apparent integer. Further, a reduced polyoxoanion and a non-reduced polyoxoanion may coexist. In addition, the electrons generated by the reduction and present in the reduced polyoxo anion are localized in the specific metal constituting the polyoxo anion, but are present throughout the polyoxo anion. Either can be used even if delocalized. Further, the reduced polyoxo anion may be in a dissociation equilibrium state of the reduced polyoxo anion of a plurality of different compositions or structures, wherein the reduced polyoxo anion has a different number of reduced electrons. It may be dissociated into reduced polyoxo anions or unreduced polyoxo anions.

On the other hand, when the polyoxoanion compound is reduced and a reduced polyoxoanion compound is prepared, 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 used as a counter cation or may be replaced with a counter cation of the polyoxoanion compound before undergoing reduction.

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

The above-mentioned various reduced polyoxoanionic compounds include those having water of crystallization.

The present invention oxidizes the thus prepared reduced polyoxoanionic compound in the presence of the catalyst of the present invention. In the present invention, the oxidation of the reduced polyoxoanion compound means that the number of reduced electrons of the reduced polyoxoanion compound is reduced. Accordingly, the reduced polyoxoanionic compound is oxidized, and the reduced polyoxoanionic compound in a more oxidized state, or the original polyoxoanionic compound, and a mixed equilibrium state thereof may be used. .

In the present invention, in the reaction of oxidizing the reduced polyoxoanionic compound, as a catalyst,
Metal compounds 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 one
There is no particular limitation as long as it contains the above-mentioned metal compound.
Examples of such a metal compound include inorganic salts such as hydrochloride, nitrate, sulfate, carbonate and phosphate of the metal, organic salts such as acetate, and complex salts such as acetylacetonate complex, carbonyl complex and ammine complex. And the like, and these inorganic salts, organic salts, complex salts and the like may be hydrates.
Further, as the metal compound, the above-mentioned metal, metal oxide, or the like can also be used. Further, these metal compounds may be supported on a carrier or the like, for example, silica, alumina, activated carbon, or other known carriers. These metal compounds may be used alone or in combination of two or more as a mixture or a composite compound.

Although 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, it is usually used per mole of the reduced polyoxoanion compound. , A metal compound in an amount of 0.0001 to 50 mol, preferably 0.000 to 50 mol.
It is about 5 to 20 mol, more preferably about 0.002 to 5 mol.

The oxidation reaction of the reduced polyoxoanionic compounds in the present invention can be carried out in a solution in which they are dissolved. Any solvent may be used as long as the reduced polyoxoanionic compound can be dissolved therein. Usually, water can be used and the reaction can be carried out in an aqueous solution. In the present invention, an aqueous solvent may be used alone, or acetonitrile, γ-butyrolactone, dimethylformamide, methyl ethyl ketone, sulfolane, ethanol, tertiary butyl alcohol, dioxane,
A polar solvent such as acetic acid may be mixed. 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 is a solution that can be a solution under the oxidation reaction conditions.
The oxidation reaction can be carried out at a concentration between about% by weight (saturated solution).

In the present invention, the oxidation reaction of the reduced polyoxoanionic compound is carried out by coexisting oxygen as an oxidizing agent. Although there is no particular limitation on the oxygen that can be used, usually, pure oxygen or air diluted with an inert gas such as nitrogen can be used. It is also possible to use an oxidizing agent in which oxygen has already been activated, such as an organic peracid or hydrogen peroxide, in combination. Although the abundance ratio of oxygen to the reduced polyoxoanionic compound is not particularly limited, usually, in the present oxidation reaction, an excess of 2 mol or more relative to the reduced polyoxoanionic compound is used. An amount of oxygen can be present. Since oxygen is consumed in the oxidation reaction, the reaction can be appropriately supplemented with oxygen. In the method of supplementing oxygen, the above-mentioned abundance ratio may not be particularly excessive. The reaction temperature in the present invention is not particularly limited, but is generally 0 to 200 ° C, preferably 30 to 150 ° C. The reaction pressure is from normal pressure to
It can be selected appropriately within a wide range of high pressure, and usually,
The range is from normal pressure to about 100 kg / cm ² . At this time, the partial pressure of oxygen can be appropriately selected in a range from normal pressure to about 50 kg / cm ² .

In the method of the present invention, the reaction is performed in a batch mode,
Any method such as a semi-batch method and a continuous method may be used. Usually, normal pressure, or a pressurized batch method, a normal pressure, or a pressurized semi-batch method, or a normal pressure, or a continuous pressurized method A method or the like can be adopted.

The reaction time in the present invention depends on the type of the reduced polyoxoanionic compound, the amount of the catalyst, the reaction pressure,
Since it depends on the reaction conditions such as the reaction temperature, the reaction method, etc., it cannot be uniquely defined. The reaction can be carried out. 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 described in detail with reference to the following Examples, but it goes without saying that the present invention is not limited by these Examples.

Hereinafter, in Examples and Comparative Examples, the degree of progress of the oxidation reaction is represented by the oxidation rate of the reduced polyoxoanionic compound shown below. The oxidation rate of the reduced polyoxoanion compound is calculated by the following equation (3). Oxidation rate (%) of reduced polyoxoanion compound = (AB) × 100 / A (3) where A and B are: A = reduced polyoxoanion compound before oxidation reaction Number of reduced electrons of the compound B = Number of reduced electrons of the reduced polyoxoanion compound after the oxidation reaction However, the reduced polyoxoanion compound is completely oxidized by the oxidation reaction, and the unreduced polyoxoanion In the case of a system compound, B = 0. .

In the above formula (3), the oxidation rate (%) of the reduced polyoxoanion compound is reduced by how much the number of reduced electrons of the reduced polyoxoanion compound is oxidized. The closer the value is to 100%, the more the oxidation reaction has progressed.

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

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 used as a polyoxoanion compound.
· _30H 2 O (Nippon Muki Chemical Co., Ltd.) 144.66g (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-mentioned aqueous solution of the polyoxoanion compound under stirring in an N ₂ atmosphere over 30 minutes. Furthermore, the polyoxoanionic 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. After the reaction solution was cooled to room temperature, it was diluted with water and the reduced polyoxoanionic compound was prepared to be a 0.2 mol / l aqueous solution. As a result of titration with a KMnO ₄ solution, the number of reduced electrons in the obtained reduced polyoxoanionic compound was 2 electrons. Thus, 0.2 mol / l
Two-electron reduced polyoxoanion compound H ₅ P
An Mo ₆ W ₆ O ₄₀ aqueous solution was obtained. 0.2 mol of the above
/ L 2-electron reduced polyoxoanion compound
30 ml of an aqueous solution of H ₅ PMo ₆ W ₆ O ₄₀ (two-electron reduced polyoxoanion compound H ₅ PMo ₆ W
₆ O ₄₀ 6.0 mmol) and lanthanum nitrate hexahydrate (La (NO ₃ ) ₃ .6H) as a catalyst
₂ O) _0.0520g of (0.12 mmol) were charged into a Teflon stirring blade with 100ml autoclave, press-fitting the oxygen 4 kg / cm ² (absolute pressure), agitation speed 800
The reaction was carried out 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 completion of the reaction, the reaction solution is allowed to cool, and then the reaction solution is treated with KMn
As a result of titration with an O ₄ solution, the oxidation rate of the polyoxoanionic 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.
_This means that 18.1% of the ₄₀ reduced electrons have been lost.

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 polyoxoanionic compound.
(0.12 mmol), except that the same reaction as in Example 1 was performed. As a result, the oxidation rate of the reduced polyoxoanionic compound was 13.5%.

Comparative Example 1 The same reaction as in Example 1 was performed, except that lanthanum nitrate hexahydrate was not added in the oxidation of the reduced polyoxoanionic compound.
As a result, the oxidation rate of the reduced polyoxoanionic 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 polyoxoanionic compound.
Example 1 except that 7 g (0.12 mmol) was used.
And the same reaction was performed. As a result, the oxidation rate of the reduced polyoxoanionic 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 polyoxoanionic compound.
(0.12 mmol), except that the same reaction as in Example 1 was performed. As a result, the oxidation rate of the reduced polyoxoanionic compound was 10.8%.

Example 5 In Example 1, titanium oxide tetrahydrate (Ti (SO ₄ ) ₂ .4H ₂ ) was used in place of lanthanum nitrate hexahydrate in the oxidation of the reduced polyoxoanionic compound.
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 polyoxoanionic compound is 1
0.6%.

Example 6 In Example 1, in place of lanthanum nitrate hexahydrate in the oxidation of the reduced polyoxoanionic compound, indium sulfate nonahydrate (In ₂ (SO ₄ ) _3.
The same reaction as in Example 1 was performed except that 0.0816 g (0.12 mmol) of 9H ₂ O) was used. As a result, the oxidation rate of the reduced polyoxoanionic 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
The same reaction as in Example 1 was performed except that 0.0533 g (0.12 mmol) of (H ₂ O) was used. As a result, the oxidation rate of the reduced polyoxoanionic 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
Except ₂ O) for using 0.0521g (0.12mmol) was conducted in exactly the same reaction as in Example 1. As a result, the oxidation rate of the reduced polyoxoanion compound was 8.6%.

Example 9 In Example 1, the reduced polyoxoanion was used.
Of lanthanum nitrate hexahydrate in the oxidation of compounds
In addition, zirconium chloride octahydrate (ZrCl ₂O ・
8H₂O) using 0.0387 g (0.12 mmol)
Except for this, 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, 0.0430 g of tantalum chloride (TaCl ₅ ) was used instead of lanthanum nitrate hexahydrate in the oxidation of the reduced polyoxoanionic compound.
The same reaction as in Example 1 was performed except that 12 mmol) was used. As a result, the oxidation rate of the reduced polyoxoanionic compound was 5.5%. Example 11 In Example 1, instead of lanthanum nitrate hexahydrate in the oxidation of the reduced polyoxoanionic compound, 0.0195 g of vanadyl sulfate (VOSO ₄ ) (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 polyoxoanionic 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
Except ₂ O) for using 0.0526g (0.12mmol) was conducted in exactly the same reaction as in Example 1. As a result, the oxidation rate of the reduced polyoxoanionic 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
Except ₂ O) for using 0.0460g (0.12mmol) was conducted in exactly the same reaction as in Example 1. As a result, the oxidation rate of the reduced polyoxoanionic 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 polyoxoanionic compound was 4.0%.
Met.

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

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

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

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

Example 19 The same reaction as in Example 2 was performed, except that the reaction temperature was changed to 100 ° C. in the oxidation of the reduced polyoxoanionic 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
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 polyoxoanionic 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 Muki Chemical Co., Ltd.) 11.74g (5m
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 the dropping funnel. This was added dropwise to the above-mentioned aqueous solution of the polyoxoanion compound under stirring in an N ₂ atmosphere over 30 minutes. The polyoxoanionic compound was further 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 0.02 mol / l aqueous solution of the reduced polyoxoanionic compound (containing 1 wt% H ₃ PO ₄ ). . K
From the titration with the MnO ₄ solution, the reduced polyoxoanion compound obtained had 4 reduced electrons. Thus, the 0.02 mol / l 4-electron reduced polyoxoanion compound H ₇ PMo ₁₂ O
_{A 40} aqueous solution (containing 1% by weight of H ₃ PO ₄ ) was obtained.

The above 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)
0.60 mmol of ₁₂ O ₄₀ ) and 0.0520 g (0.10 g) of lanthanum nitrate hexahydrate as a catalyst
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 mixture was reacted at 60 ° C. for 30 minutes while stirring at a stirring speed of 800 rpm. In the reaction, oxygen was supplied and supplemented so that the pressure during the reaction became constant. After the reaction, the reaction solution was allowed to cool and titrated with a KMnO ₄ solution. As a result, the oxidation rate of the polyoxoanion compound reduced by the reaction was 23.6%.

That is, the polyoxoanion compound H ₇ PMo ₁₂ O ₄₀ reduced by four electrons by this reaction.
23.6% of the reduced electrons have disappeared.

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 (Nippon Muki Chemical Co., Ltd.) 114.79g (5
0 mmol) and 100 ml of water were added to dissolve the polyoxoanion compound. H ₂ NNH ₂
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 polyoxoanionic compound solution over 30 minutes while stirring under an N ₂ atmosphere. The polyoxoanionic compound was further 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-green. After the reaction solution was cooled to room temperature, it was diluted with water and the reduced polyoxoanionic compound was prepared to be a 0.2 mol / l aqueous solution.

From the measurement of visible-near infrared absorption spectrum, the reduced polyoxoanionic compound obtained had 2 reduced electrons. In this way, 0.2 mol
/ 12 Electron-reduced polyoxoanionic compound H
_An aqueous solution of ₇ PMo ₁₀ V ₂ O ₄₀ was obtained.

The above-mentioned 0.2 mol / l two-electron reduced polyoxoanion compound H ₇ PMo ₁₀ V ₂ O
30 ml of ₄₀ aqueous solution (two-electron reduced polyoxoanion compound H ₇ PMo ₁₀ V ₂ O ₄₀ 6.0
mmol) and lanthanum nitrate-6 as a catalyst
0.0520 g (0.12 mmol) of the hydrate was charged into a 100 ml autoclave with a stirring blade made of Teflon,
Oxygen 4 kg / cm ² (absolute pressure) is injected and stirring speed is 80
The reaction was carried out 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 the reaction was completed, the reaction solution was allowed to cool, and the reaction solution was measured for visible-near infrared absorption spectrum. The oxidation rate of the polyoxoanion compound reduced by this reaction was 1%.
It was 6.6%.

That is, the polyoxoanion compound H ₇ PMo ₁₀ V ₂ O reduced by two electrons by this reaction.
_This means that 16.6% of the ₄₀ reduced electrons have been lost.

Example 23 A reaction was carried out in the same manner as in Example 22 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 polyoxoanionic compound was 18.1%.

[0064]

According to the present invention, by using a metal compound as a catalyst, a reduced polyoxoanion compound can be smoothly oxidized by oxygen. Conventionally, oxidation of a reduced polyoxoanionic compound, which has been a problem, can be catalytically promoted by the present invention, and the present invention relates to a process using a polyoxoanionic compound as a catalyst. It is of extremely high utility value industrially.

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C01G 1/00 B01J 27/19 C01G 39/00 C01G 41/00

Claims (1)

(57) [Claims] 1. A method for oxygen-oxidizing a reduced polyoxoanionic compound in a liquid phase, wherein the catalyst comprises lanthanum, zinc, bismuth, antimony, titanium, indium, samarium, cerium, zirconium, tantalum,
A method for oxidizing a reduced polyoxoanion compound, comprising using a metal compound containing at least one metal selected from vanadium, neodymium, gallium, nickel and niobium.