JP5299992B2 - Metal nanoparticle catalyst and oxygen oxidation method - Google Patents

Description

Aqueous solution The invention, metal nanoparticles as a catalyst, relates oxidation reaction method using the oxygen in the oxidizing agent, more particularly, the gold nanoparticles, where the amphiphilic polymer is dissolved in water And a method for producing an oxidized product by selectively oxidizing an organic compound by using oxygen as an oxidizing agent using the catalyst.

  In the present invention, for example, when an alcohol is oxidized to synthesize corresponding aldehydes, ketones, and carboxylic acids, these products are produced under mild conditions using oxygen contained in the air as an oxidizing agent. Is a highly active catalyst comprising an aqueous dispersion of metal nanoparticles and capable of serving as a medium, and a dispersion of metal nanoparticles. Is used to provide a new technology related to energy-saving and environment-friendly oxidation reactions that do not dissolve metals, can be recycled, and do not use organic media.

  Metal nanoparticles, particularly gold nanoparticles, are one of highly active catalysts. In the chemical industry, for example, oxidation reaction of carbon monoxide (Non-Patent Documents 1 to 4), α, β-unsaturated aldehyde Oxidation reaction (Non-patent documents 5), Alkene oxidation reaction (Non-patent documents 7 to), Alcohol oxidation reaction (Non-patent documents 9 to), Hydrogen peroxide solution synthesis (Non-patent documents 11 and 12), etc. And it plays a very important role.

  Alcohol oxidation reactions using gold nanoparticles have been extensively researched and developed so far, but nanoparticles easily aggregate and have a significantly reduced surface area that can be used as a catalyst. There exists a problem that activity falls easily. Therefore, gold nanoparticle catalysts using metal oxides such as alumina, silica, and titania as a support have been developed. However, since these catalysts are also heterogeneous catalysts, there are fewer opportunities for contact between the substrate and the catalyst and the reaction efficiency is low as compared with homogeneous catalysts.

  On the other hand, a method using a polymer as a carrier has also been reported (Patent Document 1). This method uses a catalyst in which a gold cluster is supported on a styrene polymer, and a catalyst is prepared for the purpose of performing an oxidation reaction in an organic medium as a heterogeneous catalyst.

  On the other hand, due to the recent increase in environmental problems, research and development of organic synthesis methods aiming at de-organic solvent has been actively carried out, for example, oxidation of alcohol using supercritical carbon dioxide, use of gold-supported metal oxide catalyst in water. The reactions that have occurred have been studied.

  Conventionally, as an industrial oxidation reaction, a method of synthesizing acetaldehyde from methanol by a dehydrogenation reaction using a metal catalyst (Carbide & Carbon Corp.), or an oxidative dehydrogenation reaction using a metal catalyst in the presence of oxygen. There are methods. These have a reaction temperature of 270 ° C. to 300 ° C., and the conversion rate is also limited to 30% to 50% in order to suppress by-products. In the presence of oxygen, acetaldehyde is synthesized by a catalytic reaction performed in the range of 450 ° C. to 550 ° C. while continuing to burn with oxygen. .

JP 2007-237116 A M.M. Haruta, N .; Yamada, T .; Kobayashi, S .; Iijima, J .; Catal. 1989, 115, 301-309 F. Moreau, G .; C. Bond, A.M. O. Taylor, J. et al. Catal. 2005, 231, 105-114 J. et al. Guzman, S.M. Carrettin, J. et al. C. Fierro-Gonzalez, Y.M. Hao, B .; C. Gates, A.M. Corma, Angew. Chem. Int. Ed. 2005, 44, 4778-4781 C. M.M. Yang, M .; Kalwei, F .; Schuth, K.M. J. et al. Chao, Appl. Catal. A 2003, 254, 289-296 J. et al. E. Bailie, G.M. J. et al. Hutchings, Chem. Commun. 1999, 2151-2152 J. et al. E. Bailie, H.C. A. Abdullah, J. et al. A. Anderson, C.I. H. Rochester, N.M. V. Richardson, N.A. Hodge, J .; G. Zhang, A .; Burrows, C.I. J. et al. Kiely, G.M. J. et al. Hutchings, Phys. Chem. Chem. Phys. 2001, 3, 4113-4121 B. Chowdhury, J .; J. et al. Bravo-Suarez, M.M. Date, S.M. Tsubota, M .; Haruta, Angew. Chem. Int. Ed. 2006, 45, 412-415 M.M. D. Hughes, Y. et al. J. et al. Xu, P .; Jenkins, P.M. McMorn, P.M. Landon, D.C. I. Enache, A .; F. Carley, G.C. A. Attard, G.M. J. et al. Hutchings, F.M. King, E .; H. Stitt, P.M. Johnston, K.M. Griffin, C.I. J. et al. Kiely, Nature 2005, 437, 1132-1135 F. Porta, L .; Prati, J .; Catal. 2004, 224, 397-403 A. Abad, P .; Conception, A.M. Corma, H .; Garcia, Angew. Chem. Int. Ed. 2005, 44, 4066-4069 P. Landon, P.M. J. et al. Collier, A.M. F. Carley, D.C. Chadwick, A.M. J. et al. Papworth, A.M. Burrows, C.I. J. et al. Kiely, G.M. J. et al. Hutchings, Phys. Chem. Chem. Phys. 2003, 5, 1917-1923 J. et al. K. Edwards, B.M. E. Solsona, P.M. Landon, A.M. F. Carley, A.M. Herzing, C.I. J. et al. Kiely, G.M. J. et al. Hutchings, J. et al. Catal. 2005, 236, 69-79

  Under such circumstances, the present inventors can solve the problems in the above-mentioned conventional technology in view of the above-mentioned conventional technology, and are energy-saving and environmentally low-load, while using oxygen as an oxidizing agent in water. However, earnest research was conducted with the goal of developing a catalyst for the efficient oxidation of alcohols under mild conditions.

  As a result, the present inventors disperse the metal nanoparticles in an aqueous solution of an amphiphilic polymer, so that the heterogeneous catalytic reaction with the metal nanoparticles is performed as in the homogeneous catalytic reaction. It has been found that the metal nanoparticles in the aqueous solution can cause an oxidation reaction and are stable even when used in the reaction or heated, and can be reused. Through repeated research, the present invention has been completed.

  The present invention generally provides an oxidation reaction catalyst that can be used as a stable and highly active catalyst or as a medium by dispersing unstable metal nanoparticles in an aqueous solution of an amphiphilic polymer. In addition, for example, in an oxygen oxidation reaction of alcohol, an efficient reaction is performed by a simple method of bubbling oxygen under mild conditions and without particularly applying pressure. It is an object of the present invention to provide an oxidation reaction method that can be put to practical use as an energy-saving industrial production technology that can be used in place of a conventional energy-loaded oxidation reaction.

  Furthermore, the present invention provides a new oxidation reaction method that does not use an organic medium, uses water as a medium, uses oxygen as an oxidizing agent, is mild, energy-saving, environmentally friendly, and does not discharge waste as much as possible. It is intended to do.

The present invention for solving the above-described problems comprises the following technical means.
The (1) metallic nanoparticles, are dispersed in an aqueous solution of the amphiphilic polymer, a catalyst to stabilize the nanoparticles, a catalyst for use in the oxidation reaction using oxygen as oxidizing agent, the metal The nanoparticles are gold nanoparticles, the gold nanoparticles have a size ranging from 2 nanometers to 20 nanometers, and the amphiphilic polymer is a polyethylene oxide-polypropylene oxide-polyethylene oxide block A catalyst for oxygen oxidation reaction of an organic compound, characterized in that it is a copolymer and has a molecular weight of 1000 to 10,000, and the oxidation reaction is a reaction for producing a ketone, carboxylic acid or ester by oxidation of an alcohol .
( 2 ) The catalyst for oxidation reaction according to (1 ) , wherein the catalyst contains sodium carbonate.
( 3 ) An oxidation reaction method for oxidizing an organic compound by oxygen using an oxidation reaction using oxygen as an oxidizing agent, using the oxidation reaction catalyst according to (1),
An oxidation reaction method, wherein the oxidation reaction is an oxidation reaction for producing a ketone, a carboxylic acid, or an ester by oxidation of an alcohol.
( 4 ) A corresponding ketone, carboxylic acid or ester is produced by oxidation of an alcohol using oxygen as an oxidizing agent using the oxidation reaction catalyst according to (1) or (2). A method for producing an alcohol oxidation product.

Next, the present invention will be described in more detail.
The present invention is a catalyst in which metal nanoparticles are dispersed in an aqueous solution of an amphiphilic polymer to stabilize the nanoparticles, and is a catalyst for use in an oxidation reaction using oxygen as an oxidant. An amphiphilic polymer is a catalyst for oxygen oxidation reaction of an organic compound, characterized in that the amphiphilic polymer is a polyalkylene oxide block copolymer.

  In addition, the present invention is an oxidation reaction method characterized in that an organic compound is oxidized with oxygen by an oxidation reaction using oxygen as an oxidizing agent, using the oxidation reaction catalyst. Furthermore, the present invention provides the production of an alcohol oxidation product characterized by producing a corresponding ketone, carboxylic acid or ester form by oxidation of an alcohol using oxygen as an oxidant using the above-mentioned oxidation reaction catalyst. Method.

In the present invention, the amphiphilic polymer is a polyethylene oxide-polypropylene oxide-polyethylene oxide type block copolymer having a molecular weight of 1000 to 10,000, an oxidation reaction is caused by oxidation of alcohol, ketone, carboxylic acid, or It is important that the reaction be an ester product. Then, in the present invention, the metal nanoparticles are gold nanoparticles, the size of the particles to be in the range of 2 nm to 20 nm and aspect of implementation, the catalyst, the sodium carbonate Containing is a preferred embodiment.

  The present invention adapts a catalyst made of metal nanoparticles stably dispersed in an aqueous solution of an amphiphilic polymer to an oxidation reaction using oxygen, thereby exhibiting an extremely high catalytic activity and is mild. Although it is a condition, a method that can be put into practical use as an energy-saving industrial production technology that enables an efficient reaction by bubbling oxygen without applying pressure, and that can replace the conventional oxidation reaction. It is to provide.

  The present invention is basically applicable to various kinds of organic reactions by using various kinds of metal nanoparticles by carrying out the reaction using the stabilized nanoparticles as a catalyst. Therefore, the type of metal and the type of reaction are not particularly limited.

  In order to demonstrate the effectiveness of the present invention, the present inventors dispersed metal nanoparticles such as gold nanoparticles in an aqueous solution of an amphiphilic polymer, using oxygen oxidation reaction of benzyl alcohol as a model reaction, Various studies were repeated on reaction yield and reaction selectivity. As a result, 99% conversion can be obtained in 8 hours under mild conditions, and benzaldehyde, benzoic acid and benzyl benzoate can be obtained with high selectivity, and other by-products can be obtained. It was confirmed that the product was easily separated because the medium was water.

In the present invention, as the metal nanoparticles child, gold nanoparticles are used.

Their to, the oxidation reaction using oxygen oxidant, for example, nanoparticles of gold having uniform size are used.

In the present invention, the smaller the size of the metal nanoparticles, the larger the surface area and the higher the activity. In the present invention, the size is in the range of 2 nm to 20 nm. If the size of the metal nanoparticles is uniform, the reaction selectivity will be improved. However, in the present invention, metal nanoparticles of these sizes may be present stably.

  In the present invention, it is necessary to disperse the metal nanoparticles in an aqueous solution of an amphiphilic polymer in order to stabilize the metal nanoparticles. As the amphiphilic polymer used in the present invention, many of the polymers that are particularly soluble in water have an effect of stabilizing metal nanoparticles, and any polymer that is soluble in water can be used. Preferably, it is a polyalkylene oxide type block copolymer having a molecular weight of 1,000 or more and 10,000 or less, and further a polyethylene oxide-polypropylene oxide-polyethylene oxide type block copolymer having a molecular weight of 1,000 or more and 10,000 or less. Most preferably it is.

In the present invention, an aqueous solution of an amphiphilic polymer is used to stabilize the metal nanoparticles, but the mixing ratio between the metal nanoparticles and the polymer is metal nanoparticles (gold nanoparticles ) / polymer. values (molar basis in units structure) 1 on 0.01 or more is a prime suitable. 00 or less, more preferably over 0.05 or more 0. 5 or less, and most preferably 0.1 or more and 0.2 or less.

  In the present invention, for example, carboxylic acid is generated by oxygen oxidation of alcohol. Therefore, the catalytic activity of the metal nanoparticles dispersed in the aqueous amphiphilic polymer solution varies depending on the acidity of the liquid. Therefore, in the catalyst dispersion in the present invention, the reaction can be allowed to proceed by setting the acidity of the solution to preferably pH 4 to 14, and more preferably the pH is set to 7 to 14. Can be advanced.

  When adjusting the pH of the aqueous solution, alkali metal or alkaline earth metal such as sodium hydroxide, potassium hydroxide, sodium hydrogen carbonate, potassium hydrogen carbonate, sodium carbonate, potassium carbonate, sodium methoxide, potassium methoxide, etc. The pH is preferably adjusted with hydroxide, carbonate or alkoxide, and organic amines such as ammonia, ethylamine, methylamine, diethylamine, dimethylamine, triethylamine, and trimethylamine, and salts thereof, more preferably alkali metals. It is preferable to adjust the pH with, for example, sodium carbonate.

  The oxidation reaction in the present invention means a method for producing a corresponding ketone, aldehyde, carboxylic acid, and ester body by oxidation of alcohol using oxygen or a gas or air containing oxygen as an oxidizing agent. It is. At that time, depending on the type of alcohol, the concentration of oxygen can be set. However, the concentration of oxygen used for oxidation is preferably not less than oxygen (20.9 Vol%) and not more than 100% oxygen contained in air. It is.

  The alcohol used in the oxidation reaction in the present invention includes aromatic and aliphatic alcohols, and the following compound group of Chemical Formula 1 can be oxidized.

(In the formula, R ₁ and R ₂ are the same or different, and are hydrogen, an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, or an aryl group, which may have a substituent. Or a member that is bonded to each other to form a ring, wherein the substituent is an aryl group, alkyl group, alkenyl group, alkynyl group, alkoxy group, formyl group, carbonyl group, carboxyl group, An alkoxycarbonyl group, a hydroxyl group, a mercapto group, a halogen, a sulfonyl group or an amino group.)

  Moreover, as a compound obtained, the compound group described below can be obtained. As a compound group to be obtained, the following chemical group 2 ketone, aldehyde compound group,

(In the formula, R ₁ and R ₂ are the same or different, and are hydrogen, an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, or an aryl group, which may have a substituent. Or a member that is bonded to each other to form a ring, wherein the substituent is an aryl group, alkyl group, alkenyl group, alkynyl group, alkoxy group, formyl group, carbonyl group, carboxyl group, An alkoxycarbonyl group, a hydroxyl group, a mercapto group, a halogen, a sulfonyl group or an amino group.)

  In addition, a compound group of carboxylic acid of the following chemical formula 3,

(In the formula, R ₁ is a member that forms hydrogen or an alkyl group, alkenyl group, alkynyl group, cycloalkyl group, or aryl group, which may have a substituent. The substituent is an aryl group, alkyl group, alkenyl group, alkynyl group, alkoxy group, formyl group, carbonyl group, carboxyl group, alkoxycarbonyl group, hydroxyl group, mercapto group, halogen, sulfonyl group or amino group.

  Furthermore, the compound group of the ester body of the following Chemical formula 4 can be mentioned.

(In the formula, R ₁ is a member that forms hydrogen or an alkyl group, alkenyl group, alkynyl group, cycloalkyl group, or aryl group, which may have a substituent. The substituent is an aryl group, alkyl group, alkenyl group, alkynyl group, alkoxy group, formyl group, carbonyl group, carboxyl group, alkoxycarbonyl group, hydroxyl group, mercapto group, halogen, sulfonyl group or amino group.

  In the present invention, when an oxidation reaction is performed to obtain various ketones, aldehydes, carboxylic acids, esters and the like, water is used as a medium, and therefore the reaction temperature is usually 0 ° C. or higher and 100 ° C. or lower. However, this can be arbitrarily set according to the type of reaction substrate, target compound, conversion rate, yield, selectivity, and the like. In addition, the reaction time is usually 1 minute or longer and 48 hours or less, and this can be appropriately applied according to the substrate, the type of reaction, the catalyst, the type of the target compound, and the like.

  In the present invention, these are not particularly limited and can be arbitrarily set. As a typical example, for example, when an oxidation reaction of benzyl alcohol is performed, the conversion rate reaches almost 100% at a reaction temperature of 30 ° C. and a reaction time of 8 hours, and benzaldehyde, benzoic acid, and benzyl benzoate can be obtained. .

  In the present invention, a batch reactor is preferably used, but a continuous reactor can be used as appropriate. Furthermore, in a reaction system that does not use an organic solvent, since water is used as a medium, separation of water and a substrate or water and a product is often very easy, and a product phase is formed on the surface of an aqueous medium. Therefore, for many organic compounds, there is an advantage that a special separation and purification process of the product after the reaction can be omitted, and the product separation process becomes simple.

The following effects are exhibited by the present invention.
(1) Conventionally, metal nanoparticles are fine particles of several nanometers, and if there is no carrier such as a surfactant or an inorganic oxide, they are easy to aggregate and unstable, but an aqueous solution of an amphiphilic polymer Since the stability has been dramatically improved, it is possible to provide a recyclable and highly active catalyst.
(2) This catalyst does not use expensive or highly dangerous oxidizers such as hydrogen peroxide or other peroxides, and is inexpensive such as oxygen or oxygen-containing gas or air. Water can be used as a reaction medium while using a substance that is easy to handle, and even under mild conditions, an oxidation reaction of alcohol or the like can be carried out efficiently, and the corresponding ketone, aldehyde, carbon An oxidation reaction method capable of obtaining an acid, an ester or the like can be provided.
(3) Further, since the method of the present invention is a reaction using water as a medium without using any organic solvent, the reaction substrate and / or product can be easily separated and recovered, and the impurities can be removed. There is little discharge and both water and catalyst can be reused. Moreover, since the reaction temperature is overwhelmingly lower than that of the conventional oxidation method and the required input energy can be reduced, the present invention is useful as providing a new general chemical oxidation method with a low environmental load. It is.

  Next, the present invention will be specifically described based on examples, but the present invention is not limited to these examples.

In this example, gold nanoparticles were synthesized by the following method. An aqueous solution of P123 (amphiphilic polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO-PEO) block copolymer (average molecular weight: 5800)) was stirred at 35 ° C. for 30 minutes, and then an HAuCl ₄ aqueous solution (0.05 M, 4 mL) was added and immediately stirred vigorously.

Next, NaBH ₄ aqueous solution (0.1%, 6 mL) was slowly added thereto over 15 minutes. Immediately after the addition, it turned into a pale yellow solution, and after 5 minutes of stirring, it turned into a wine red solution. The gold nanoparticle dispersion was prepared in the same manner as the gold and P123 molar fractions of 1 to 7.

  When the visible absorption spectrum of the obtained dispersion was measured, absorption derived from surface plasmon absorption was observed at 520 nm, and it was confirmed that gold nanoparticles were generated. Furthermore, the visible absorption spectrum of the dispersion after the heat resistance experiment heated at 80 ° C. for 8 hours and after use in the reaction experiment was also measured. As a result, absorption was observed at 520 nm, and the nanoparticles dispersed in the polymer were found to be very stable. The visible absorption spectrum of the dispersion is shown in FIG.

  Gold nanoparticles were observed using a transmission electron microscope (TEM). Three types of samples were used: a dispersion immediately after gold nanoparticle synthesis, a dispersion after a heat resistance experiment heated at 80 ° C. for 8 hours, and a dispersion after use in the reaction. One drop was dropped on the grid and then dried. The images are shown in FIGS.

  Moreover, dispersion | distribution of the gold nanoparticle in each sample is shown in FIGS. From this, it was found that immediately after the synthesis of the gold nanoparticles, the average particle size was 7.3 nm and the dispersion was 4 nm to 12 nm. On the other hand, after the heat resistance experiment, it was found that the average particle diameter of the particles was 7.3 nm, showing almost the same dispersion as 4 nm to 12 nm, but a little wider. Further, it was found that the nanoparticles after the reaction were slightly dispersed due to a phenomenon such as aggregation, and the average particle size was increased to 8.8 nm.

  X-ray diffraction (XRD) of the obtained gold nanoparticles was measured. Peaks corresponding to diffraction on the (111), (200), and (311) planes of gold were obtained, confirming the formation of crystalline gold nanoparticles. A diagram of XRD is shown in FIG.

In this example, the gold nanoparticles dispersed in the above P123 aqueous solution were used as a catalyst, and an oxidation reaction of alcohol using oxygen as an oxidizing agent was performed. 15 mL of Na ₂ CO ₃ aqueous solution (0.25 M) and 15 mL of gold nanoparticle dispersion are added to a 50 mL two-necked flask equipped with a reflux tube, and stirred at a predetermined temperature with an oil bath while stirring with a magnetic stirrer. Until heated. While stirring, oxygen was bubbled and dissolved for 30 minutes.

  Thereafter, 0.75 mL of alcohol was added and reacted for a predetermined time while bubbling oxygen and stirring vigorously. In the reaction process, measurement was performed while sampling 1 mL of solution at predetermined time intervals. After completion of the reaction, 1 mL of diluted hydrochloric acid (2M) was added, and extraction was performed 3 times with diethyl ether. The product was analyzed by gas chromatography to determine yield, selectivity and the like.

Using benzyl alcohol as a raw material, the reaction temperature was traced under the conditions of a reaction temperature of 30 ° C. and the presence of Na ₂ CO ₃ . The result is shown in FIG. In the figure, ■ represents the conversion rate of benzyl alcohol, □ represents the selectivity of benzaldehyde which is one of the products, Δ represents the selectivity of benzoic acid, and ▽ represents the selectivity of benzyl benzoate. In 8 hours, the conversion was almost 100%. Although more reactions were carried out, no change in conversion rate or other compound selectivity was observed.

  The selectivity of benzaldehyde reached a maximum (49%) 30 minutes after the start of the reaction, but as the reaction proceeded, the oxidation reaction progressed and the selectivity of benzoic acid increased. On the other hand, it was found that benzyl benzoate is produced by condensation (esterification) of benzyl alcohol and benzoic acid. The selectivity for benzyl benzoate remained almost unchanged after 1 hour. Moreover, other by-products were not obtained, and it was found that the oxidation reaction proceeds selectively by using gold nanoparticles as a catalyst.

Next, oxidation reactions of various alcohols were performed. As a catalyst, gold nanoparticles were added in an amount of 0.015 mmol in terms of molecule, Au: P123 = 1: 7 (molar ratio), 0.75 mmol of alcohol, and 3.75 mmol of Na ₂ CO ₃ were added. The reaction was carried out at a temperature of 30 ° C. while bubbling. As a result, it was found that all benzyl alcohol systems react at a conversion rate of 94% or more.

  On the other hand, alkyl alcohol (1-heptanol) was hardly oxidized and the conversion rate remained at about 27%. However, it was found that the carboxylic acid was oxidized instead of the ketone body. Further, when the reaction temperature is examined in the range of 20 ° C. to 40 ° C. like cyclooctanol, the conversion rate of 58% in 24 hours (in the case of 30 ° C.) is increased to 92% in 9 hours by increasing the temperature. Rose to. In addition, the reaction stopped with the ketone body of cyclooctanone, and carboxylic acid or the like was not obtained.

  On the other hand, when a catalyst in which gold nanoparticles or palladium or gold / palladium nanoparticles were supported on an alumina support was used, there was almost no reaction, and the conversion rate was 9% or less. Therefore, the aqueous dispersion in which the gold nanoparticles are stabilized with P123 can be handled like an aqueous solution, and further exhibits a good catalytic ability for the oxidation reaction. Although it was a particle, it was found to be very stable.

  As described above in detail, the present invention relates to a metal nanoparticle catalyst and an oxygen oxidation method. According to the present invention, metal nanoparticles can be stabilized by dispersing them in an amphiphilic polymer aqueous solution. It is possible to provide a highly active and recyclable catalyst capable of oxidizing alcohol using oxygen as an oxidizing agent. By using this catalyst, it is possible to efficiently synthesize ketones, aldehydes, carboxylic acids, and esters from various oxidation reactions.

  In addition, the present invention can be synthesized under mild conditions without using an organic medium, and generates no waste as much as possible. Therefore, the present invention is useful for providing an energy-saving environmentally low load type organic compound oxidation reaction method. It is.

UV-visible absorption spectrum of a dispersion of gold nanoparticles dispersed in an aqueous solution of P123 (amphiphilic polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO-PEO) block copolymer (average molecular weight: 5800)), and In the figure, (a) is the dispersion after heating the dispersion at 80 ° C. for 8 hours, (b) is the dispersion before heating, and (c) is used for the oxidation reaction. A later dispersion. The transmission electron microscope (TEM) photograph of the dispersion liquid after heating a dispersion liquid at 80 degreeC for 8 hours is shown. The transmission electron micrograph of the dispersion liquid just after adjustment is shown. The electron micrograph of the dispersion liquid after using for an oxidation reaction is shown. The particle size distribution in a dispersion liquid after heating a dispersion liquid at 80 degreeC for 8 hours is shown. The particle size distribution of the dispersion immediately after adjustment is shown. The particle size distribution of the dispersion liquid after being used for the oxidation reaction is shown. The powder X-ray diffraction of the gold nanoparticle disperse | distributed to P123 aqueous solution is shown. The oxidation reaction of benzyl alcohol by the gold nanoparticle catalyst disperse | distributed to P123 aqueous solution is shown.

Claims (4)

The metal nanoparticles are dispersed in an aqueous solution of the amphiphilic polymer, a catalyst to stabilize the nanoparticles, oxygen A catalyst for use in oxidation reactions with the oxidant, the metal nanoparticles Gold nanoparticles, the gold nanoparticles having a size in the range of 2 to 20 nanometers, and the amphiphilic polymer is a polyethylene oxide-polypropylene oxide-polyethylene oxide block copolymer A catalyst for oxygen oxidation reaction of an organic compound, wherein the molecular weight is 1000 to 10,000, and the oxidation reaction is a reaction for producing a ketone, a carboxylic acid, or an ester by oxidation of an alcohol. The oxidation catalyst according to claim 1, wherein the catalyst contains sodium carbonate. An oxidation reaction method for oxidizing an organic compound by oxygen using an oxidation reaction using oxygen as an oxidant using the oxidation reaction catalyst according to claim 1,
An oxidation reaction method, wherein the oxidation reaction is an oxidation reaction for producing a ketone, a carboxylic acid, or an ester by oxidation of an alcohol. 3. Production of an alcohol oxidation product, wherein the corresponding ketone, carboxylic acid or ester is produced by oxidation of an alcohol using oxygen as an oxidizing agent using the catalyst for oxidation reaction according to claim 1 or 2. Method.