JP2002331244A - Supported type titanium dioxide catalyst and method for oxidizing aromatic compound using the catalyst - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photocatalyst useful for efficiently oxidizing an aromatic compound. SOLUTION: The supported type titanium dioxide catalyst is obtained by supporting titanium dioxide fine particles on the surfaces of rutile type titanium dioxide particles in a dispersed state. In this catalyst, it is preferable to support titanium dioxide fine particles with a specific surface area of 30 m<2> /g or more on the surfaces of the rutile type titanium dioxide particles in a dispersed state. The ratio of the titanium dioxide fine particles supported on the surfaces of the rutile type titanium dioxide particles in a dispersed state and the rutile type titanium dioxide particles is, for example, former/latter (weight ratio) = about 0.1/99.9-99.5/0.5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel titanium dioxide catalyst, a method for oxidizing an aromatic compound using the catalyst, and a method for producing an aromatic compound containing an oxygen atom.

[0002]

2. Description of the Related Art Oxygen atom-containing aromatic compounds (aromatic oxidation products) such as aromatic aldehydes and quinones obtained by oxidation of aromatic compounds are compounds useful as organic synthetic chemicals or intermediate materials thereof. is there. As a method for oxidizing an aromatic compound, a method using a reagent comprising a combination of hydrogen peroxide and a reducing agent such as iron (II) sulfate, ascorbic acid, ethylenediaminetetraacetic acid, hydrogen peroxide and boron trifluoride etherate, aluminum chloride And a method using a reagent composed of a combination of an organic peracid or a peroxide and a Lewis acid, and the like. However, these methods generally have drawbacks such as low yield, reaction rate and selectivity of the reaction are easily affected by reaction conditions. In addition, since relatively expensive reagents and reagents that require complicated post-treatment are used, they cannot be said to be industrially advantageous.

[0003] On the other hand, research has been made vigorously to convert light energy into chemical energy using a semiconductor photocatalyst and to use the converted energy for decomposing harmful substances or synthesizing useful compounds. In this method, the reaction can be performed at about room temperature,
It has great advantages such as being mild to the environment,
In recent years, studies have been made on the oxidation of aromatic compounds. For example, Japanese Patent Application Laid-Open No. 2000-336051 discloses a method for producing hydroxynaphthalenes, which comprises oxidizing naphthalenes under ultraviolet irradiation in the presence of a semiconductor photocatalyst such as titanium dioxide. However, this method is not always satisfactory in terms of the yield and selectivity of the oxidation reaction product.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a photocatalyst useful for efficiently oxidizing an aromatic compound. Another object of the present invention is to provide a method for efficiently oxidizing an aromatic compound under light irradiation. Still another object of the present invention is to provide a method for efficiently producing a corresponding oxygen atom-containing aromatic compound by oxidizing an aromatic compound under light irradiation.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies in order to achieve the above object, and as a result, have found that the use of a titanium dioxide photocatalyst having a specific structure can efficiently oxidize aromatic compounds. The present invention has been completed.

That is, the present invention provides a supported titanium dioxide catalyst in which titanium dioxide fine particles are dispersed and supported on the surface of rutile type titanium dioxide particles. In a preferred embodiment of this catalyst, fine particles of titanium dioxide having a specific surface area of 30 m ² / g or more are dispersed and supported on the surface of rutile titanium dioxide particles having a particle diameter of 100 nm or more. The ratio of the titanium dioxide fine particles dispersed and supported on the surface of the rutile type titanium dioxide particles to the rutile type titanium dioxide particles is the former /
The latter (weight ratio) = 0.1 / 99.9 to 99.5 / 0.5
The degree is preferred.

The present invention also provides the oxidation of aromatic compounds with molecular oxygen and / or peroxides under light irradiation in the presence of the supported titanium dioxide catalyst to produce corresponding oxidation products. A method for oxidizing an aromatic compound is provided.

[0008] The present invention further provides a method of oxidizing an aromatic compound with molecular oxygen and / or peroxide under light irradiation in the presence of the above-mentioned supported titanium dioxide catalyst to form a corresponding aromatic aldehyde compound and / or a corresponding aromatic aldehyde compound. Alternatively, the present invention provides a method for producing an oxygen atom-containing aromatic compound for producing quinones.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION [Supported Titanium Dioxide Catalyst] The feature of the supported titanium dioxide catalyst of the present invention is that titanium dioxide fine particles are formed on the surface of rutile type titanium dioxide particles (hereinafter sometimes referred to as "particle A"). (Hereinafter may be referred to as “particle B”). Such a titanium dioxide catalyst has remarkably high photocatalytic activity as compared with unsupported ordinary rutile-type titanium dioxide, anatase-type titanium dioxide, or a simple mixture thereof.

According to the studies conducted by the inventors so far, rutile-type titanium dioxide has a higher oxidizing power than anatase-type titanium dioxide, but generally has a smaller amount of oxygen adsorbed on the particle surface and has a lower reducing side. Has the disadvantage that the electron transfer to oxygen, which is the reaction of In addition, the potential of the conductor of the rutile type titanium dioxide is -0.5 V [vs.
(Saturated calomel electrode)], from the relationship with the potential of one-electron reduction of oxygen -0.56 V, it is inferred that the transfer process of the excited electrons to oxygen is rate-limiting. However, when titanium dioxide fine particles such as anatase type titanium dioxide are carried on the surface of such rutile type titanium dioxide, the surface area of the catalyst apparently increases, and the amount of adsorbed oxygen increases, so that the reduction reaction of oxygen (oxygen It is considered that the transfer of the excited electrons to the substrate is greatly promoted, whereby the reaction efficiency (catalytic activity) is dramatically increased.

In the supported titanium dioxide catalyst of the present invention, the particle diameter of the particles A may be large enough to function as a carrier for titanium dioxide fine particles (particles B), for example, 100 nm or more (about 100 to 2000 nm). ), Preferably 150 nm or more (150 to 1000 n
m). The particle diameter of the particles B can be appropriately selected within a range in which the particles B can be supported on the particles A as a carrier.
m (about 1 to 90 nm), preferably 70 nm or less (for example, about 2 to 70 nm). The specific surface area of the particles B is preferably 30 m ² / g or more (for example, 30 m ² / g).
~200m about ² / g), more preferably 40 m ² / g
This is the above (for example, about 40 to 150 m ² / g). If the specific surface area of the particles B is too small, the catalytic activity tends to decrease. The particles B may be any of anatase-type titanium dioxide fine particles, rutile-type titanium dioxide fine particles, and a mixture thereof.

In the supported titanium dioxide catalyst of the present invention, if the ratio of the particles B to the particles A (the former / the latter) is too large, the particles B cover the surface of the particles A as a carrier,
Excitation light does not effectively hit the particles A, and the catalytic activity tends to decrease. Conversely, if the ratio between the particles B and the particles A (the former / the latter) is too small, the catalytic activity tends to decrease, probably because the amount of adsorbed oxygen does not increase so much. Therefore, the ratio of the particles B to the particles A (the former / the latter) is generally 0.1 / 99.9 to 99.5 / 0.5, preferably 1/99 to 95/5, more preferably 2/9. 98-65
/ 35, particularly preferably about 5/95 to 50/50 (particularly 15/85 to 45/55).

[0013] The supported titanium dioxide catalyst of the present invention is prepared, for example, by placing a rutile-type titanium dioxide powder functioning as a carrier and a titanium dioxide powder dispersed and supported on the surface thereof in an appropriate solvent and subjecting the powder to ultrasonic treatment for a predetermined time. Can be prepared. In addition, although anatase type titanium dioxide generally has very small primary particles, it forms a large aggregate having an average particle size of about 10 μm, and when this is subjected to ultrasonic treatment together with rutile type titanium dioxide particles, anatase type titanium dioxide is obtained. The primary particles generated by dissolving the aggregates of titanium dioxide are dispersed and supported on the rutile titanium dioxide particles.

[0014] As the solvent used in the ultrasonic treatment,
There is no particular limitation, for example, aliphatic hydrocarbons such as hexane, alicyclic hydrocarbons such as cyclohexane, aromatic hydrocarbons such as toluene, halogenated hydrocarbons such as methylene chloride, ethers such as diethyl ether and tetrahydrofuran, Examples thereof include nitriles such as acetonitrile, esters such as ethyl acetate, ketones such as acetone, amides such as N, N-dimethylformamide, water, and mixed solvents thereof. Preferred solvents include polar solvents such as acetonitrile, water, or mixed solvents thereof.

The temperature of the ultrasonic treatment is not particularly limited, but is usually about 0 to 100 ° C, preferably about 10 to 50 ° C. The ultrasonic treatment time is, for example, 10 minutes or more (1
0 to 120 minutes), preferably 15 minutes or more (15 to 6 minutes).
0 minutes). If the ultrasonic treatment time is too short, it is difficult to form a structure in which anatase-type or rutile-type fine particles are dispersed and supported on rutile-type particles.

[Aromatic Compound Oxidation Method and Oxygen Atom-Containing Aromatic Compound Production Method] In the method of the present invention, the aromatic compound used as the substrate has an aromatic carbon ring or heterocyclic ring, and The compound is not particularly limited as long as it has at least one site to be oxidized. As the compound having an aromatic carbon ring, for example, benzene, naphthalene, biphenyl, indene, indane, tetralin, 2,2'-binaphthyl, acenaphthene, fluorene, phenanthrene, anthracene, triphenylene,
Pyrene, chrysene, naphthacene, coronene and the like. Further, as a compound having an aromatic heterocyclic ring,
Nitrogen-containing compounds such as pyridine, indole and quinoline,
Examples include oxygen-containing compounds such as furan and benzofuran, and sulfur-containing compounds such as thiophene and benzothiophene.

Aromatic carbocycle in the aromatic compound
Alternatively, a substituent is bonded to the heterocycle as long as the reaction is not inhibited.
May be combined. As the substituent, for example, halogen
Atom, hydroxyl group, mercapto group, substituted oxy group
[For example, methoxy, ethoxy, propoxy, isopro
Alkoxy groups such as oxy and butoxy groups (preferably C
_1-4Aryloxy such as phenoxy group)
A group such as an acetyloxy or propionyloxy group;
Siloxy group etc.), substituted thio group (for example, methylthio
E, alkylthio groups such as ethylthio group), carbo
Xyl group, substituted oxycarbonyl group (for example, methoxy
Carbonyl, ethoxycarbonyl, propyloxycal
C such as bonyl group_1-4Alkoxy-carbonyl group
), Substituted or unsubstituted carbamoyl groups, acyl groups (ace
C such as tyl, propionyl and benzoyl groups_2-11Acyl
Group), cyano group, nitro group, substituted or unsubstituted amino
Group (for example, amino group; N, N-dimethylamino group, etc.)
N, N-di C_1-4Alkylamino group; N-acetyla
NC such as a mino group_2-11Acylamino group), alk
(E.g., methyl, ethyl, propyl, isopropyl
C, such as butyl, butyl, isobutyl and t-butyl groups_1-4A
Alkyl group), alkenyl group (for example, vinyl group,
C such as a ril group_2-4Alkenyl group), alkynyl group
(For example, C such as ethynyl group)_2-4Alkynyl group
), Cycloalkyl groups (eg, cyclopentyl,
3- to 8-membered cycloalkyl groups such as clohexyl
), Aryl groups (eg, phenyl, naphthyl, etc.)
C_6-14Aryl group).

Further, a non-aromatic carbon ring or heterocyclic ring may be condensed with the aromatic carbocyclic ring or heterocyclic ring in the aromatic compound. Examples of such a non-aromatic carbon ring include a 3- to 8-membered cycloalkane ring such as a cyclopentane ring and a cyclohexane ring. As the non-aromatic heterocyclic ring, at least one heteroatom selected from a nitrogen atom, an oxygen atom, and a sulfur atom such as a pyrrolidine ring, an oxolane ring, a thiolane ring, a piperidine ring, and a tetrahydropyran ring may be used. And a 3- to 8-membered heterocyclic ring.

In the method of the present invention, the amount of the supported titanium dioxide catalyst used is, for example, 1 to 100 parts by weight, preferably 5 to 60 parts by weight, and more preferably 100 parts by weight of the aromatic compound used as the substrate. Is about 10 to 30 parts by weight.

In the method of the present invention, an aromatic compound as a substrate is oxidized with molecular oxygen and / or peroxide under light irradiation. As the light to be irradiated, ultraviolet light having a wavelength of 390 nm or less is usually used, but visible light can also be used. The preferred wavelength range of light is 420 nm or less (part of visible light and ultraviolet light).

As molecular oxygen, pure oxygen may be used, or oxygen or air diluted with an inert gas such as nitrogen, helium, argon or carbon dioxide may be used. The amount of molecular oxygen used is, for example, 0.5 mol or more, preferably 1 mol or more, per 1 mol of the aromatic compound used as the substrate. Often an excess molar molecular oxygen is used relative to the aromatic compound.

The peroxide is not particularly limited, and any of peroxide, hydroperoxide and the like can be used.
Representative peroxides include hydrogen peroxide, cumene hydroperoxide, t-butyl hydroperoxide, triphenylmethyl hydroperoxide, t-butyl peroxide, benzoyl peroxide, and the like. Although pure hydrogen peroxide may be used as the hydrogen peroxide, it is usually used in a form diluted with an appropriate solvent, for example, water (for example, 30% by weight of hydrogen peroxide) from the viewpoint of handleability. Can be The amount of the peroxide used is, for example, about 0.1 to 5 mol, preferably about 0.3 to 1.5 mol, per 1 mol of the aromatic compound used as the substrate.

In the present invention, only one of molecular oxygen and peroxide may be used, but the combination of molecular oxygen and peroxide may greatly improve the reaction rate.

The reaction is usually performed in the presence of a solvent. Examples of the solvent include aliphatic hydrocarbons such as hexane, heptane, octane, ligroin, and petroleum ether; alicyclic hydrocarbons such as cyclopentane, cyclohexane, and cycloheptane; ethers such as ethyl ether, isopropyl ether, and tetrahydrofuran. Esters such as ethyl acetate; acetonitrile, propionitrile,
Nitriles such as butyronitrile and benzonitrile;
An aprotic polar solvent such as N-dimethylformamide;
Organic acids such as acetic acid; water; and mixed solvents thereof.

The reaction temperature can be appropriately selected in consideration of the reaction rate and the reaction selectivity, but is generally -20 ° C to 100 ° C.
It is about. The reaction is often performed near room temperature. The reaction may be performed by any method such as a batch system, a semi-batch system, and a continuous system.

By the above reaction, corresponding oxidative cleavage products (for example, aromatic aldehyde compounds), quinones, and oxygen-containing aromatic compounds such as hydroxyl-containing aromatic compounds are formed from the aromatic compounds. For example,
From naphthalene, 2-formylcinnamaldehyde (oxidative cleavage product), 1,4-naphthoquinone and the like are produced. The production ratio (selectivity) of these products can be adjusted by appropriately selecting reaction conditions and the like.

The reaction product can be separated and purified by, for example, separation means such as filtration, concentration, distillation, extraction, crystallization, recrystallization, and column chromatography, or a combination of these. Further, the titanium dioxide catalyst can be easily separated by filtration, and the separated catalyst can be recycled after being subjected to a treatment such as washing as required.

[0028]

According to the present invention, an aromatic compound can be efficiently oxidized under light irradiation, and for example, an aromatic aldehyde compound and an oxygen-containing aromatic compound such as quinones can be efficiently produced. .

[0029]

EXAMPLES The present invention will be described below in more detail with reference to Examples, but the present invention is not limited to these Examples. Analysis and identification of the reaction products are performed by capillary gas chromatography, high performance liquid chromatography,
The measurement was performed by GC-mass spectrum and nuclear magnetic resonance spectrum. The specific surface area of titanium dioxide is determined by Micromeritics
The measurement was performed using a surface area measuring device “FlowSorb II 2300” manufactured by the company.

Example 1 An anatase type titanium dioxide powder [trade name "ST-01", anatase type content 100%, Ishihara Sangyo Co., Ltd.] was placed in a 30 ml internal irradiation type reactor equipped with a cooling pipe and an oxygen supply pipe. ), Average particle diameter 7 nm, specific surface area 236 m ² /
g] and rutile-type titanium dioxide powder [trade name “NS-5”
1 ", rutile type (rutile type content 98.6%), manufactured by Toho Titanium Co., Ltd., average particle diameter 200 nm, specific surface area 6.
5m ² / g] and the ratio of anatase-type titanium dioxide to rutile-type titanium dioxide is 9/1 (total amount: 0.015 g), and 0.1 g of naphthalene and acetonitrile are added thereto. 3.63 g, water 0.3 g
And sonicated at room temperature for 30 minutes. While stirring the reaction solution with a stirrer piece, oxygen gas was blown at a flow rate of 2 ml / min at room temperature, and light irradiation was performed for 1 hour using a 500 W ultra-high pressure mercury lamp. At this time, in order to avoid direct excitation of naphthalene due to light irradiation, 340
Light was irradiated through a filter that cuts light of sub-nm or less. Light irradiation was performed while dispersing the titanium dioxide powder using a stirrer. The reaction mixture was filtered, and the filtrate was quantitatively analyzed by high performance liquid chromatography. as a result,
6.9 μmol of 2-formylcinnamaldehyde,
2.7 μmol of 1,4-naphthoquinone was produced. [Spectral data of 2-formylcinnamaldehyde] ¹ H-NMR (CDCl ₃ ) δ: 6.67 (1H, dd,
J = 16.1, 7.8 Hz), 7.6-8.0 (4H,
m), 8.58 (1H, d, J = 16.1 Hz), 9.
81 (1H, d, J = 7.8 Hz), 10.23 (1
H, s) MS (m / z): 131 (M ⁺ -29).

Example 2 An anatase type titanium dioxide powder [trade name "S"
T-01 ", content of anatase type 100%, manufactured by Ishihara Sangyo Co., Ltd., average particle diameter 7 nm, specific surface area 236 m ² /
g] and rutile-type titanium dioxide powder [trade name “NS-5”
1 ", rutile type (rutile type content 98.6%), manufactured by Toho Titanium Co., Ltd., average particle diameter 200 nm, specific surface area 6.
5m ² / g] as in Example 1 except that the ratio of anatase-type titanium dioxide to rutile-type titanium dioxide was weighed so that the former / latter = 7/3 (total amount 0.015 g). Was performed. As a result, 10.9 μmol of 2-formylcinnamaldehyde and 2.2 μmol of 1,4-naphthoquinone were produced.

Example 3 An anatase type titanium dioxide powder [trade name "S"
T-01 ", content of anatase type 100%, manufactured by Ishihara Sangyo Co., Ltd., average particle diameter 7 nm, specific surface area 236 m ² /
g] and rutile-type titanium dioxide powder [trade name “NS-5”
1 ", rutile type (rutile type content 98.6%), manufactured by Toho Titanium Co., Ltd., average particle diameter 200 nm, specific surface area 6.
5m ² / g] as in Example 1 except that the ratio of anatase-type titanium dioxide to rutile-type titanium dioxide was weighed such that the former / latter = 5/5 (total amount 0.015 g). Was performed. As a result, 15.1 μmol of 2-formylcinnamaldehyde and 2.8 μmol of 1,4-naphthoquinone were produced.

Example 4 An anatase type titanium dioxide powder [trade name "S"
T-01 ", content of anatase type 100%, manufactured by Ishihara Sangyo Co., Ltd., average particle diameter 7 nm, specific surface area 236 m ² /
g] and rutile-type titanium dioxide powder [trade name “NS-5”
1 ", rutile type (rutile type content 98.6%), manufactured by Toho Titanium Co., Ltd., average particle diameter 200 nm, specific surface area 6.
5m ² / g] as in Example 1 except that the ratio of anatase-type titanium dioxide to rutile-type titanium dioxide was the former / latter = 3/7 (total amount 0.015 g). Was performed. As a result, 15.6 μmol of 2-formylcinnamaldehyde and 3.7 μmol of 1,4-naphthoquinone were produced.

Example 5 An anatase type titanium dioxide powder [trade name "S"
T-01 ", content of anatase type 100%, manufactured by Ishihara Sangyo Co., Ltd., average particle diameter 7 nm, specific surface area 236 m ² /
g] and rutile-type titanium dioxide powder [trade name “NS-5”
1 ", rutile type (rutile type content 98.6%), manufactured by Toho Titanium Co., Ltd., average particle diameter 200 nm, specific surface area 6.
5 m ² / g] as in Example 1 except that the ratio of anatase-type titanium dioxide to rutile-type titanium dioxide was weighed such that the former / latter = 1/9 (total amount 0.015 g). Was performed. As a result, 15.7 μmol of 2-formylcinnamaldehyde and 1.8 μmol of 1,4-naphthoquinone were produced.

Example 6 An anatase type titanium dioxide powder [trade name "S"
T-01 ", content of anatase type 100%, manufactured by Ishihara Sangyo Co., Ltd., average particle diameter 7 nm, specific surface area 236 m ² /
g] and rutile-type titanium dioxide powder [trade name “NS-5”
1 ", rutile type (rutile type content 98.6%), manufactured by Toho Titanium Co., Ltd., average particle diameter 200 nm, specific surface area 6.
5m ² / g] was measured as in Example 1 except that the ratio of anatase-type titanium dioxide to rutile-type titanium dioxide was 1/49 (the total amount was 0.015 g). Was performed. As a result, 12.8 μmol of 2-formylcinnamaldehyde and 0.9 μmol of 1,4-naphthoquinone were produced.

Example 7 An anatase type titanium dioxide powder [trade name "S"
T-01 ", content of anatase type 100%, manufactured by Ishihara Sangyo Co., Ltd., average particle diameter 7 nm, specific surface area 236 m ² /
g] and rutile-type titanium dioxide powder [trade name “NS-5”
1 ", rutile type (rutile type content 98.6%), manufactured by Toho Titanium Co., Ltd., average particle diameter 200 nm, specific surface area 6.
5m ² / g] was measured as in Example 1 except that the ratio of anatase-type titanium dioxide to rutile-type titanium dioxide was 1/98 (the total amount was 0.015 g). Was performed. As a result, 10.1 μmol of 2-formylcinnamaldehyde and 0.8 μmol of 1,4-naphthoquinone were produced.

Example 8 An anatase type titanium dioxide powder [trade name "S"
T-01 ", content of anatase type 100%, manufactured by Ishihara Sangyo Co., Ltd., average particle diameter 7 nm, specific surface area 236 m ² /
g] and rutile-type titanium dioxide powder [trade name “NS-5”
1 ", rutile type (rutile type content 98.6%), manufactured by Toho Titanium Co., Ltd., average particle diameter 200 nm, specific surface area 6.
5m ² / g], except that the ratio of anatase-type titanium dioxide to rutile-type titanium dioxide is the former / latter = 1/374 (total amount 0.015 g),
The same operation as in Example 1 was performed. As a result, 8.0 μmol of 2-formylcinnamaldehyde and 0.75 μmol of 1,4-naphthoquinone were produced.

Comparative Example 1 An anatase type titanium dioxide powder [trade name "ST-01", anatase type content 100%, Ishihara Sangyo Co., Ltd.] was placed in an external irradiation type reactor having a 30 ml inner volume equipped with a cooling pipe and an oxygen supply pipe. ), Average particle diameter 7 nm, specific surface area 236 m ² /
g] was weighed, and 0.1 g of naphthalene, 3.63 g of acetonitrile, and 0.3 g of water were added thereto. While stirring the reaction solution with a stirrer piece,
At room temperature, oxygen gas is blown at a flow rate of 2 ml / min,
Light irradiation was performed for 1 hour using a 500 W ultra-high pressure mercury lamp. At this time, in order to avoid direct excitation of naphthalene due to light irradiation, light irradiation was performed through a filter that cuts light of 340 nm or less. Light irradiation was performed while dispersing the titanium dioxide powder using a stirrer. The reaction mixture was filtered, and the filtrate was quantitatively analyzed by high performance liquid chromatography. As a result, 2-formylcinnamaldehyde contained 1.
4 μmol, 0.75 μmol of 1,4-naphthoquinone
Had been generated.

Comparative Example 2 Rutile-type titanium dioxide powder [trade name "N" was placed in a 30-ml internal irradiation reactor equipped with a cooling pipe and an oxygen supply pipe.
S-51 ", rutile type (rutile type content 98.6%), manufactured by Toho Titanium Co., Ltd., average particle diameter 200 nm, specific surface area 6.5 m ² / g]. .1 g, acetonitrile 3.63 g,
0.3 g of water was added. While stirring the reaction solution with a stirrer piece, oxygen gas was blown at a flow rate of 2 ml / min at room temperature, and light irradiation was performed for 1 hour using a 500 W ultra-high pressure mercury lamp. At this time, in order to avoid direct excitation of naphthalene due to light irradiation, light irradiation was performed through a filter that cuts light of 340 nm or less. Light irradiation was performed while dispersing the titanium dioxide powder using a stirrer.
The reaction mixture was filtered, and the filtrate was quantitatively analyzed by high performance liquid chromatography. As a result, 4.6 μmol of 2-formylcinnamaldehyde and 0.4 μmol of 1,4-naphthoquinone were produced.

Example 9 A reactor was charged with rutile-type titanium dioxide powder [Catalyst Society of Japan Reference Catalyst “JRC-TIO-3”, average particle diameter 40 nm, specific surface area 48.1 m ² / g] and rutile-type titanium dioxide powder [ Brand name “NS-51”, rutile type (rutile type content 9
8.6%), manufactured by Toho Titanium Co., Ltd., average particle size 20
0 nm and a specific surface area of 6.5 m ² / g] were measured in the same manner as in Example 1 except that the ratio was the former / the latter = 7/3 (total amount: 0.015 g). Was done. As a result, 2-formylcinnamaldehyde was reduced to 2
2.3 μmol, 1.9 μmo of 1,4-naphthoquinone
l had been generated.

Example 10 A reactor was charged with rutile-type titanium dioxide powder [Catalyst Society of Japan Reference Catalyst “JRC-TIO-3”, average particle size: 40 nm, specific surface area: 48.1 m ² / g] and rutile-type titanium dioxide powder [Product name "NS-51", rutile type (rutile type content 9
8.6%), manufactured by Toho Titanium Co., Ltd., average particle size 20
0 nm and a specific surface area of 6.5 m ² / g] were measured in the same manner as in Example 1 except that the ratio of the former and the latter was 5/5 (total amount: 0.015 g). Was done. As a result, 1-formylcinnamaldehyde was 1
6.4 μmol, 1.8 μmo of 1,4-naphthoquinone
l had been generated.

Example 11 A reactor was charged with rutile-type titanium dioxide powder [catalyst, reference catalyst “JRC-TIO-3”, average particle diameter 40 nm, specific surface area 48.1 m ² / g] and rutile-type titanium dioxide powder [ Brand name “NS-51”, rutile type (rutile type content 9
8.6%), manufactured by Toho Titanium Co., Ltd., average particle size 20
0 nm and a specific surface area of 6.5 m ² / g] were measured in the same manner as in Example 1 except that the ratio was the former / the latter = 3/7 (total amount: 0.015 g). Was done. As a result, 1-formylcinnamaldehyde was 1
8.3 μmol, 2.3 μmo of 1,4-naphthoquinone
l had been generated.

Analysis of Particle Structure of Titanium Dioxide Catalyst Titanium dioxide catalyst prepared in Example 5 (catalyst after ultrasonic treatment), titanium dioxide catalyst prepared in Example 8 (catalyst after ultrasonic treatment), Comparative Example 1 Titanium dioxide catalyst used in
The particle image of the titanium dioxide catalyst used in Comparative Example 2 was observed with a scanning electron microscope (SEM). The SEM photographs are shown in FIGS.

[Brief description of the drawings]

FIG. 1 is a scanning electron micrograph showing the particle structure of a titanium dioxide catalyst (catalyst after ultrasonic treatment) prepared in Example 5 (corresponding to a horizontal length of the photograph = 1092 nm).

FIG. 2 is a scanning electron micrograph showing the particle structure of the titanium dioxide catalyst (catalyst after ultrasonic treatment) prepared in Example 8 (corresponding to a lateral length of the photograph of 800 nm).

FIG. 3 is a scanning electron micrograph showing the particle structure of the titanium dioxide catalyst used in Comparative Example 1 (corresponding to the horizontal length of the photograph = 1092 nm).

FIG. 4 is a scanning electron micrograph showing the particle structure of a titanium dioxide catalyst used in Comparative Example 2 (corresponding to the horizontal length of the photograph = 1092 nm).

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C07C 45/36 C07C 45/36 46/04 46/04 47/548 47/548 50/12 50/12 / C72B 61/00 300 C07B 61/00 300 (72) Inventor Teruhisa Yokono 3-9-11 Keyakizaka, Kawanishi-shi, Hyogo F-term (reference) 4G069 AA03 AA08 BA04A BA04B BA48A CB07 DA08 EA01X EA01Y EB18X EB18Y EC01X EC03Y EC22 FA01 FA02 FB06 FB58 FC08 4H006 AA02 AC44 BA10 BA30 BA95 BE30 4H039 CA62 CC40 CC50

Claims (5)

[Claims] 1. A supported titanium dioxide catalyst in which titanium dioxide fine particles are dispersed and supported on the surface of rutile titanium dioxide particles. 2. The supported titanium dioxide catalyst according to claim 1, wherein titanium dioxide particles having a specific surface area of 30 m ² / g or more are dispersed and supported on the surface of the rutile titanium dioxide particles having a particle diameter of 100 nm or more. 3. The ratio of the titanium dioxide fine particles dispersed and supported on the surface of the rutile type titanium dioxide particles to the rutile type titanium dioxide particles is the former / the latter (weight ratio) = 0.
The ratio is 1 / 99.9 to 99.5 / 0.5.
The supported titanium dioxide catalyst according to the above. 4. An aromatic compound is oxidized with molecular oxygen and / or peroxide under light irradiation in the presence of the supported titanium dioxide catalyst according to claim 1. A method for oxidizing an aromatic compound, which comprises producing an oxidation product. 5. An aromatic compound is oxidized with molecular oxygen and / or peroxide under light irradiation in the presence of the supported titanium dioxide catalyst according to any one of claims 1 to 3, A method for producing an oxygen-containing aromatic compound, which comprises producing an aromatic aldehyde compound and / or quinones.