JP2008264761A - New alloy nano colloidal particle and chemical reaction using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for synthesizing PdZn alloy nano colloidal particles and utilizing them as a dehydrogenation catalyst of an alcohol compound or the like. <P>SOLUTION: A compound containing Pd in molecular structure, a compound containing Zn in molecular structure, a reducing agent, a coordinate organic molecule and a solvent are mixed to an uniform mixture. Heating the mixture starts reduction reaction to produce alloy PdZn particles and immediately after that, particle surfaces are covered with the coordinate organic molecules. By this method, the nano colloidal particle having uniform alloy PdZn inside the particle can be synthesized. Moreover such an alloy nano colloidal particle can be utilized as a catalyst for dehydrogenation reaction of the alcohol compound. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a novel alloy nanocolloid particle and a catalytic reaction using the same. More specifically, the present invention relates to a PdZn alloy nanocolloid particle and a catalyst used in a dehydrogenation reaction or hydrogenation reaction using the same.

  Alloy nanocolloid particles having an average particle diameter of about 1 to 50 nm (hereinafter referred to as “nanocolloid particles”) are expected to be applied in various fields because of their specific surface area. In particular, the catalyst used for the catalytic reaction is often a noble metal, and nanocolloid particles having a large specific surface area are preferred because of their excellent cost performance.

Bronstein et al. Have attempted to synthesize palladium-zinc (hereinafter abbreviated as PdZn) nanocolloidal particles using a polystyrene-vinylpyridine diblock polymer (J. Catal., 196, 302 (2000)). In this document, nanoparticles with a composition of Pd ₇₆ Zn ₂₄ and an average particle size of 1.5 to 2 nm are obtained, but vinylpyridine, which is a hydrophilic part in a polymer in a hydrophobic aqueous solvent, is a micelle. Since the nanoparticles are synthesized using the formation, the micelles are close to a solid state, the synthesized nanoparticles are not uniform at the atomic level, and fine zinc clusters are separated in the palladium particles. Cluster-in-cluster type particles.

  The same document discloses that the obtained nanocolloid particles can be used as a hydrogenation catalyst. Specifically, the carbon-carbon defect of 3,7-dimethyloctaen-6-ol-3 (DiHL) is disclosed. An example in which a saturated bond is hydrogenated has been reported.

By the way, an element selected from Group 10 of the Periodic Table of Elements, particularly palladium (hereinafter abbreviated as Pd), has a catalytic activity to dehydrogenate and carbonylate alcohol under a low pressure of ordinary pressure. Is well known. Recently, it has been reported that the use of PdZn instead of palladium results in higher activity than that of Pd (Applied Catalysis).
A: General Vol. 267, 9-16 (2004)). The reason is that Pd and Zn form an alloy. However, the average particle size and the particle size distribution of these nanoparticles are 3.24 nm for the activated carbon-supported product (standard deviation of particle size is 32% with respect to the average particle size) and 8.86 nm (52% for the zinc oxide-supported product). ) And the particle size distribution is known to be wide.
Journal of Catalysis, 196, 302-314 (2000) Applied Catalysis A: General Vol. 267, 9-16 (2004)

  The above PdZn is produced by impregnating a support such as activated carbon with a metal salt of Pd or Zn and then firing in a reducing atmosphere. The resulting particles have a wide particle size distribution and many particles smaller than 2 nm. Exists. Such fine particles are thermodynamically unstable and have a melting point lower than that of the bulk, and melt at a high temperature exceeding 200 ° C. or dissolve in a liquid phase reaction. For this reason, there is a problem of lack of durability when used in a catalytic reaction. On the other hand, when the particle diameter is 50 nm or more, the specific surface area with respect to the volume of the particles increases, and the activity per weight of the catalyst decreases.

  In addition, when an alloy is formed by this method, the composition of individual particles usually varies, which causes multiple crystal structures and reduces the proportion of crystal structures effective for catalytic reactions. was there. Therefore, even if PdZn nanocolloid particles are synthesized by the method of Bronstein etc., the particles obtained are not alloys, but show the properties as pure Pd, that is, the hydrogenation ability, but show the properties as the alloy PdZn, ie, the dehydrogenation ability I can't expect that.

  The present invention has been made as a result of investigations for improving the above-mentioned present situation, and it is an object of the present invention to provide a higher performance alloy nanoparticle and to provide a method of using it as a dehydrogenation catalyst for alcohol compounds and the like. .

  As a result of intensive studies to solve the above problems, the inventors of the present invention mixed a compound containing Pd in the molecular structure, a compound containing Zn in the molecular structure, a reducing agent, a coordinating organic molecule, and a solvent. The nanoparticle colloidal particles, which are uniform in the interior of the alloy PdZn, are synthesized by a method in which a reduction reaction is initiated by uniformizing and heating to generate fine particles of the alloy PdZn, and immediately after that, the particle surface is covered with coordinating organic molecules. I found what I could do. And it discovered that the nanoparticle of such an alloy could be utilized as a catalyst for dehydrogenation reaction of an alcohol compound, and completed this invention.

That is, the first gist of the present invention is an element selected from group 10 of the periodic table (hereinafter referred to as “A”) and an element selected from group 12 of the periodic table (hereinafter referred to as “B”). )) And has an average particle size of 1 nm to 50 nm. (Claim 1) At this time, it is preferable that the standard deviation of the particle size is 30% or less with respect to the average particle size.
At this time, it is preferable that A is palladium and B is zinc. Moreover, it is preferable that it is a composition represented by the following general formula at this time.

A _(100-X) B _X
(X represents a number of 30 to 80)

  Furthermore, it is preferable that a coordinating organic molecule having a molecular weight of 15000 or less is bonded to the surface of the particle.

  The second gist of the present invention resides in a nanocolloid carrier in which the nanocolloid particles are supported on a carrier (claim 6).

  The third gist of the present invention resides in a catalyst for dehydrogenation reaction of an alcohol compound comprising the nano colloid particles or the nano particle colloid carrier (claim 7).

  The fourth gist of the present invention is to produce a homogeneous solution by mixing a compound containing A in the molecular structure, a compound containing B in the molecular structure, a reducing agent, a coordinating organic molecule and a solvent, Subsequently, the homogeneous solution is heated to produce fine particles of the alloy AB, and then the surface of the fine particles is covered with a coordinating organic molecule. 8).

  A fifth aspect of the present invention resides in a method for producing a carbonyl compound, characterized in that the alcohol compound is dehydrogenated using the nanocolloid particles or nanocolloid support.

  ADVANTAGE OF THE INVENTION According to this invention, the nanoparticle which can be utilized as a catalyst which can dehydrogenate reaction of alcohol can be provided, and the manufacturing method of a carbonyl compound can be provided using the particle | grain.

  The present invention will be described below with reference to embodiments. However, the present invention is not limited to the following embodiments, and can be arbitrarily modified and implemented without departing from the gist of the present invention.

[Nano colloidal particles]
The nanocolloid particles of the present invention are made of an alloy containing two or more metal elements, and usually a protective layer is formed on the surface thereof.

[Composition of nano colloidal particles]
The nanocolloid particles of the present invention are composed of an alloy containing two kinds of metal elements. One of the two types of metal elements is selected from elements selected from group 10 of the periodic table (hereinafter referred to as “A”), and the other is selected from group 12 of the periodic table. It is selected from elements (hereinafter referred to as “B”). Among the Group 10 elements, palladium (Pd) is preferably used, and among the Group 12 elements, zinc (Zn) is preferably used.

  The alloy has a plurality of crystal structures with different stable crystal phases depending on the composition at room temperature of about 20 ° C. Here, what is meant by the word “alloy” is different from a cluster-in-cluster structure or a core-shell structure in which A and B are individually present in the same particle, and is mixed at an atomic level. If they are mixed at the atomic level, the unit cell in the crystal structure is different from that in the case of a mixture of pure metals, so that the crystal structure can be known by an analysis technique such as X-ray diffraction.

  There are multiple types of stable crystal structures depending on the composition and temperature. These crystal structures can be known from the phase diagram of the alloy. When an alloy is used as a catalyst, it is usually difficult to confirm which crystal structure has a high activity.

Alloy AB is an alloy of Group 10 and Group 12, and is considered to have similar physical properties, so that a preferable range of composition can be defined by taking PdZn as an example.
_{Specifically,} when expressed as _{Pd (100-X) Zn X} , the range of preferred X as catalysts 30 or 80 or less, more preferably 40 or more 70 or less, and most preferably 45 or more and 60 or less.

  Moreover, materials other than the two types of alloys may be included as an additive. For example, elements of Groups 13 to 16, such as carbon (C) and oxygen (O) are mentioned. The ratio of these additives is 10% or less, preferably 5% or less, relative to the number of atoms in the alloy.

[Average particle size and particle size distribution of nano colloidal particles]
The average particle size of the nanocolloid particles of the present invention is 1 nm or more and 50 nm or less. Here, what is described as an average particle diameter means an average value obtained by observing with a transmission electron microscope and measuring the size of 300 particles individually.
Specifically, the calculation is performed as follows. That is,
Nano colloidal particles are dispersed in hexane at a concentration of 0.01 wt%, dropped onto a carbon grid for transmission electron microscope (TEM) observation, dried in air, and then set on a TEM sample stage. Three-field imaging is performed at a magnification of 600,000 times at an applied voltage of 200 kV of an electron beam during observation. Randomly select 300 particles from the captured particles and measure the horizontal length of the photo. These values are averaged to obtain an average particle size. Further, a value obtained by dividing the standard deviation of the measured value by the average particle size and multiplying by 100 is used as an index representing the particle size distribution.

  When considering use as a catalyst, it is preferable that the average particle size is small in order to increase the specific surface area. However, if it is too small, the crystal lattice of the nanocolloid particles becomes unstable and melts during the reaction at high temperature. Disappears. Further, when the average particle size is increased, the specific surface area is decreased, and the catalytic activity per weight of the alloy is decreased. For these reasons, the range of the average particle size is more preferably 2 nm or more and 25 nm or less, and most preferably 2.5 nm or more and 15 nm or less.

  When the particle size distribution is wide, small particles of 2 nm or less and large particles of 50 nm or more are included, so that the durability as a catalyst is lacking or the activity becomes low for the same reason as described above. Therefore, the standard deviation is preferably 30% or less with respect to the average particle diameter, more preferably 25% or less, and most preferably 20% or less.

[Protective layer of nano colloidal particles]
A protective layer is provided in order to improve the dispersibility with respect to the medium (after-mentioned) of a nano colloid particle. The organic compound forming the protective layer holds a portion having a coordination ability to the metal in the molecular structure, and is bonded to the surface of the alloy nanoparticle at the portion. Such an organic compound is called a coordinating organic compound.

  A specific type of the coordinating organic compound is not particularly limited as long as the reaction substrate can be brought into contact with the surface of the nanocolloid particles when used for the catalytic reaction, and an appropriate one may be selected according to the medium.

  Examples of such coordinating organic compounds include carboxylic acid compounds, amine compounds, phosphine compounds, phosphine oxide compounds, and the like. In addition, a coordination organic compound may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

  If the molecular weight of the coordinating organic compound is too small, the protective layer becomes thin, particles are aggregated, and the specific surface area is reduced. On the other hand, if the molecular weight becomes too large, the protective layer becomes too thick to be supported on the carrier, and the reaction substrate cannot reach the particle surface and the activity is not increased. For these reasons, the preferred molecular weight is 50 or more and 15000 or less, more preferably 100 or more and 5000 or less, and most preferably 200 or more and 500 or less.

[Production method of nano colloidal particles]
The production method of the nano colloidal particles in the present invention can be produced using, for example, a known product solvent precipitation method, thermal decomposition method, reverse micelle method, polyol method and the like.

Hereinafter, an example of a method for producing PdZn nanocolloid particles will be described.
When producing PdZn nanocolloid particles, a coordinating organic compound, a reducing agent, and a solvent for forming a metal raw material and a particle protective layer are charged into a reactor and heated under an inert atmosphere to synthesize the particles. Among the metal raw materials, examples of the Group 10 element raw materials include metal complexes such as palladium acetylacetonate, tetrakis (triphenylphosphine) palladium, tris (dibenzylideneacetone) dipalladium, and metal salts such as palladium chloride and palladium acetate. As the Group 12 element raw material, for example, metal complexes such as zinc acetylacetonate and zinc phthalocyanine, metal salts such as zinc chloride and zinc acetate, and organic metals such as dimethylzinc and diethylzinc can be used.

  The coordinating organic compound preferably has a high boiling point so that it can be applied to a reaction at a high temperature, but has a molecular weight limitation as described above. The ratio of the number of moles of the group 10 element used to the number of moles of the group 12 element is variable depending on the composition of the target alloy, but is usually 1/10 to 10, preferably 1/5 to 5, more preferably. 1/2 to 2. If the concentration of the metal raw material is too low, there is no precipitation as crystals and no particles are formed. On the other hand, if the concentration is too high, the degree of supersaturation is too large, resulting in fine particles, or secondary agglomeration of particles proceeds and cannot be recovered as single particles.

  Therefore, the concentration of the sum total of the metal raw materials in the reaction solution is usually 0.0005 to 5 mmol / mL, preferably 0.005 to 0.5 mmol / mL, and more preferably 0.01 to 0.1 mmol / mL.

  Coordinating organic substances are usually carboxylic acid compounds such as oleic acid, stearic acid, palmitic acid, adamantane carboxylic acid, alkylamine compounds such as oleylamine, octadecylamine, hexadecylamine, trioctylphosphine, triphenylphosphine, etc. Phosphine compounds, phosphine oxide compounds such as trioctyl phosphine oxide and tributyl phosphine oxide, and thiol compounds such as dodecane thiol, hexadecane thiol and octadecane thiol. Moreover, you may use these coordination organic substance in mixture of multiple types.

  The amount of the coordinating organic compound used relative to the metal raw material is usually 0.01 to 200 times the molar amount, preferably 0.1 to 20 times the molar amount, and most preferably 0.5 to 5 times the amount. The reducing agent preferably has a high boiling point so as to be used for a high temperature reaction. Examples include diols such as hexanediol, hexadecanediol, triethylene glycol, and tetraethylene glycol, polyols such as polyethylene glycol, and the like. Depending on the type of raw material, the reduction reaction may proceed even without the use of a reducing agent.

  The amount of the reducing agent to be used with respect to the metal raw material is usually 0 to 100 times mol, preferably 0.1 to 10 times mol, and more preferably 0.5 to 5 times mol. As the solvent, those having a high boiling point are preferable so as to be used in a high-temperature reaction, and examples thereof include ethers such as dioctyl ether and diphenyl ether. Depending on the type and amount of the coordinating organic compound, the reduction reaction may proceed even without the use of a solvent.

  The amount of the solvent used is preferably 0 to 2000 mL / mmol, more preferably 2 to 200 mL / mmol, and most preferably 5 to 50 mL / mmol with respect to the number of moles of the metal raw material.

  The above raw materials are used after being mixed in the reactor, but there is no particular limitation on the order of mixing, and everything may be charged from the beginning, or a certain kind of raw material may be added after the start of heating. .

  The reaction is carried out under an inert atmosphere, and the inert atmosphere is usually carried out under a nitrogen or argon atmosphere. The reaction temperature is variable depending on the type of raw material and reducing agent, but is usually 80 to 500 ° C, preferably 150 to 450 ° C, more preferably 250 to 400 ° C. The reaction time refers to the time after the reaction temperature is reached, and is usually 0 to 120 minutes, preferably 1 to 60 minutes, and more preferably 5 to 30 minutes.

  In addition, the particle size and particle size distribution change depending on the rate of temperature rise until reaching the reaction temperature. A preferable temperature increase rate is 2 to 5000 ° C./min, preferably 5 to 1000 ° C./min, and more preferably 10 to 100 ° C./min.

  After the reaction, the reaction mixture is cooled to about 70 ° C. in an inert atmosphere, and a poor solvent such as ethanol is added to precipitate the nanoparticle colloidal particles, which are purified and collected by centrifugation or the like.

[Method of controlling particle size, particle size distribution and composition of nano colloidal particles]
In order to control the average particle size of the nanocolloid particles, for example, the concentration of the metal raw material may be changed. That is, the concentration of the metal raw material can be selected from 0.0005 to 5 mmol / mL, but among these, when the concentration is close to 5 mmol / mL, the degree of supersaturation increases during the reaction and many fine nuclei are generated. Therefore, the particle size becomes small. On the other hand, when the concentration is lower than 0.0005 mmol / mL, the diameter becomes larger.

  In order to control the particle size distribution of the nanocolloid particles, for example, the temperature increase rate during the reaction may be changed. That is, the rate of temperature rise can be selected from 2 to 5000 ° C./min. Among them, when the temperature is raised at a slow rate close to 2 ° C./min, nucleation continues and the particle size distribution becomes wider. Conversely, when the temperature is raised at a fast rate close to 5000 ° C./min, the nucleation is completed in a short time, so the particle size distribution tends to be narrow.

  In order to control the composition of the nanocolloid particles, for example, it is also effective to change the mixing ratio of the carboxylic acid compound and the alkylamine compound. For example, taking the production of PdZn alloy nanoparticles as an example, if a large amount of carboxylic acid is used, Pd will be excessive, and conversely if a large amount of alkylamine is used, Zn will be excessive.

  This is because, for example, when the affinity between carboxylic acid and Zn is high and there is a large amount of carboxylic acid, the amount of Zn taken into the particles decreases, resulting in an excess of Pd. Conversely, alkylamine has a high affinity with Pd and alkylamine In many cases, it is devised as one of the causes that the amount of Pd taken into the particles is reduced and Zn is excessive as a result.

[Supporting method of nano colloidal particles on a carrier]
The nanocolloid particles synthesized in this study can be used as a catalyst in a state dispersed in a liquid, but can be used by being supported on a carrier. It is preferable to use it as a supported catalyst by supporting it on a carrier because a catalytic reaction can be carried out with a flow device and productivity is improved.

  Examples of usable carriers include silica gel, activated carbon, alumina, zeolite and other porous materials having a large specific surface area, fine carbon such as carbon black, and the like. If impurities are contained, the impurities may cause a side reaction, so that a pure material is preferable. Silica gel is preferably used.

  There is no limitation on the shape of the silica gel, but a uniform spherical shape with a size of about 2 to 10 mm is preferable in order not to block the reactor. When preparing a supported catalyst, nano colloidal particles are dispersed in a hydrophobic solvent such as hexane, and the liquid is brought into contact with beads of silica gel. Thereafter, a supported catalyst having nano colloidal particles supported on the surface can be obtained by filtration. The concentration of the nanocolloid particles in the supported catalyst is 0.1 to 90 wt%, preferably 0.5 to 50 wt%, more preferably 1 to 10 wt% with respect to the support.

[How to use nano colloidal particles]
Nano colloidal particles synthesized in this study can be used as catalysts. After synthesis, the nanocolloid particles isolated by centrifugation are dispersed in the reaction raw material and heated at normal pressure to be used as a dehydrogenation catalyst. At this time, the nanocolloid particles may be used in a state of being dispersed in a solvent that is not a reaction raw material, and the concentration of the nanocolloid particles in the reaction solution is 0.5 to 5000 mg / mL, preferably 5 to 500 mg / mL, More preferably, it is 10-250 mg / mL.

  Alcohol compounds are often used as reaction raw materials when used as a catalyst. Examples thereof include monovalent alcohol compounds such as methanol, ethanol, propanol and butanol, divalent alcohol compounds such as ethylene glycol, propanediol and butanediol, and polyhydric alcohol compounds such as polyethylene glycol, preferably divalent. Alcohols and polyhydric alcohols, most preferably divalent alcohols.

  The reaction temperature is 80 to 230 ° C., preferably 100 to 220 ° C., and most preferably 150 to 215 ° C. when dehydrogenating 1,4-butanediol at normal pressure. Further, the synthesized nanocolloid particles may be used by being supported on the above-mentioned carrier. In this case, a reaction using a distribution device is also possible, so that productivity is improved. When carrying out the flow reaction, the flow rate of the raw material liquid with respect to the nanocolloid supported catalyst is 0.01 to 200 mL / g · Hr, preferably 0.02 to 100 mL / g · Hr, more preferably 0.05 to 50 mL / g · Hr. It is.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to the following examples, and may be arbitrarily modified and implemented without departing from the gist of the present invention. it can.

[Analysis method]
The method for obtaining the average particle size is as follows. Nanocolloid particles were dispersed in hexane at a concentration of 0.01 wt%, dropped on a carbon grid for transmission electron microscope (TEM) observation, dried in air, and then set on a TEM sample stage. The TEM model was a Hitachi transmission electron microscope H-9000UHR. Three-field imaging was performed at a magnification of 600,000 times at an applied voltage of 200 kV of an electron beam during observation. Randomly 300 particles were selected from the captured particles and the horizontal length of the photo was measured. These values were averaged to obtain an average particle size. The method for obtaining the particle size distribution is as follows. The standard deviation of the measured particle size value is divided by the average particle size, and a value obtained by multiplying the value by 100 is used as an index representing the particle size distribution.

  When elemental analysis was performed using TEM, measurement was performed using FEI Tecnai G2 F20 microscope attached to TEM. At that time, there were a case where composition analysis was performed for the entire wide field of view including about a hundred particles and a case where composition analysis was performed by focusing on one particle.

When analyzing the average composition of more particles as a whole, the atomic absorption spectrometer Jobin
It calculated | required using ICP-AES JY38S made from Yvon.

  RINT200PC made by Rigaku was used as the X-ray diffractometer. CuKα rays (wavelength 1.542 angstroms) were used as the X-ray light source. For example, the sample was dispersed in hexane at a concentration of 10 mg / mL, dropped on a quartz substrate having a size of 15 mm square, dried and dropped repeatedly to prepare a laminated film of nanocolloid particles and used for measurement.

  In order to evaluate the dehydrogenation reaction performance of 1,4-butanediol, Shimadzu Gas Chromatography GC-14A was used. DB-WAX manufactured by Agilent Technologies was used for the column. 1 mL of the reaction solution was extracted from the flask and filtered, and 0.1 g of the reaction solution was diluted with 10 mL of dioxane and analyzed.

<Example 1>
[Synthesis 1 of PdZn nano colloidal particles]
In a 50 mL four-neck round bottom flask, 152 mg (0.5 mmol) of palladium acetylacetonate manufactured by Aldrich as a raw material of palladium, 132 mg (0.5 mmol) of zinc acetylacetonate monohydrate manufactured by Strem as a raw material of zinc, as a reducing agent Aldrich 1,2-hexanediol 260 mg (1.0 mmol), Aldrich oleic acid 0.64 mL (molecular weight 282.46, 2.0 mmol) as a coordinating organic compound, another coordinating organic compound Aldrich oleylamine (2.72 mL, molecular weight 267.49, 8.0 mmol), octyl ether 17 mL (56.6 mmol) as a solvent, and magnetic stirrer bar are charged, and a reflux tube is provided to allow argon gas to flow. It was set in the reactor.

  The remaining flask mouth was covered with a natural rubber septa, and a thermocouple was inserted into one of them so that the internal temperature of the flask could be measured. While rotating with a magnetic stirrer at a rotation speed of 800 times per minute, vacuuming was performed, and the operation of introducing argon gas and abdominal pressure was repeated three times to keep the system in an argon atmosphere. The flask contents were turbid brown. When the temperature was raised to 295 ° C. at a heating rate of 10 ° C./min using a mantle heater, the reaction solution turned black, indicating that the reduction reaction proceeded. After maintaining at 295 ° C. for 30 minutes, the mantle heater was removed and the mixture was cooled to 70 ° C. When ethanol bubbled with nitrogen from the septa was added to the 40 mL flask, the liquid color changed to black turbidity and nanocolloid particles were precipitated.

When this liquid was centrifuged at a speed of 4000 revolutions per minute for 1 minute, the supernatant became clear and brown, and the black solid at the bottom of the centrifuge tube was recovered by decantation. Next, a colorless and transparent liquid obtained by adding 100 μL of oleic acid and 100 μL of oleylamine to 40 mL of hexane bubbled with nitrogen was added to the black precipitate in total and subjected to ultrasonic treatment for 1 minute in an ultrasonic cleaning bath to obtain a uniform black liquid. This liquid was centrifuged again at a speed of 4000 rpm for 1 minute to obtain a black PdZn nanocolloid particle dispersion with a supernatant. When the metal concentration in the liquid was measured by ICP elemental analysis, Pd was 0.187 wt%, Zn was 0.085 wt%, and the composition of the alloy was Pd ₅₇ Zn ₄₃ .

  The operation of dipping 0.5 mL of the PdZn nanocolloid particle dispersion liquid drop by drop on the glass substrate and drying was repeated to produce a PdZn nanoparticle laminated film. When this film was analyzed by a powder X-ray diffractometer (CuKα ray), it showed a main peak at 40.9 °. In addition to the main peak, there was a peak at 43.9 °, and it was confirmed to exist as a shoulder on the right side of the main peak. These peak positions coincided with the peak positions of PdZn in the alloy.

  When one drop of the PdZn nanocolloid particle dispersion was dropped on a carbon grid, dried, and observed with a transmission electron microscope, many particles having a size of 5 to 10 nm were present. Since each particle was independent, it was found that a coordinating organic compound was present on the surface of the particle to form a protective layer. The average particle size was 8.5 nm. Moreover, the standard deviation of the particle diameter with respect to the average particle diameter was 19.3%.

  When the composition of each particle was analyzed by TEM-EDX, all the analyzed particles contained Pd and Zn. From these facts, it became clear that uniform PdZn alloy nanocolloid particles that are not core-shell structures or cluster-in-cluster could be synthesized.

<Example 2>
[Supporting PdZn Nanocolloidal Particles on Silica Gel Support]
Example 1 A white silica gel particle of 10 to 20 mesh (particle size: 780 to 1,700 μm) of silica gel carrier CARiACT Q-15 (average pore size: 15 nm) manufactured by Fuji Silysia Chemical Co., Ltd. was placed in a 30 mL vial. 10.8 mL of PdZn nanocolloid particle dispersion was poured from above. Covered and left to stand at room temperature for 3 days. When the silica gel particles were collected by filtration through a membrane filter, the color changed to black, and a nanocolloid support was obtained. The filtrate had a uniform transparent light black color. When the nanocolloid carrier was analyzed by ICP elemental analysis, it contained 1.35 wt% Pd and 0.74 wt% Zn.

<Example 3>
[Supporting PdZn nanocolloid particles on activated carbon support]
5 g of black pellets (major axis 6 mm, minor axis 2 mm) of activated carbon Sorbororit 2X (average pore size: 920 nm) manufactured by Norit were placed in a 30 mL vial.
20 mL of dZn nanocolloid particle dispersion was poured from above. Covered and left to stand at room temperature for 3 days. The activated carbon pellets were collected by filtration through a membrane filter to obtain a nanocolloid carrier. The filtrate was colorless and uniform and transparent. When the nanocolloid carrier was analyzed by ICP elemental analysis, it contained Pd 1.1 wt% and Zn 0.5 wt%.

<Example 4>
[Dehydrogenation of alcohol in nano colloidal particle dispersion]
When 120 mL of the PdZn nanoparticle dispersion liquid of Example 1 was placed in a 25 mL round bottom flask and hexane in the PdZn nanoparticle dispersion liquid was distilled off while applying nitrogen gas, 1061 mg of a viscous black liquid was obtained. 1,4-Butanediol 5 mL (56.6 mmol) manufactured by Aldrich was added and the temperature was raised to 200 ° C. and kept for 5 hours. A part of the reaction solution was extracted with a glass syringe, diluted with acetone and analyzed by gas chromatography, and a peak of γ-butyrolactone was confirmed. The amount produced was 4.1 mmol. From this, it was found that cyclization dehydrogenation of 1,4-butanediol occurred using PdZn nanocolloid particles as a catalyst. Subsequently, the reaction temperature was raised to 215 ° C. and maintained for 3 hours. When a part of the reaction solution was extracted, diluted with acetone and analyzed by gas chromatography, the peak of γ-butyrolactone became large. On the other hand, it was found that the peak of 1,4-butanediol disappeared and the reaction proceeded 100%.

  40 mL of ethanol bubbled with nitrogen was added to the reaction solution, and purified by centrifugation to obtain a black solid. This solid was transferred to a 25 mL round bottom flask, 5 mL (56.6 mmol) of 1,4-butanediol was added, the temperature was raised to 215 ° C. and kept for 3 hours. When a part of the reaction solution was extracted and analyzed by gas chromatography, 25 mmol of γ-butyrolactone was produced. From this, it was found that the PdZn nanocolloid particles can be recycled as a catalyst.

  Further, when the crystal structure of the black solid recovered from the recycled reaction solution was analyzed with a powder X-ray diffractometer (CuKα ray), it showed a main peak at 40.9 °, almost the same as the diffraction pattern of the PdZn nanocolloid particles before the reaction. Matched. It was shown that there was no change in the crystal structure even after dehydrogenation of 1,4-butanediol at a high temperature of 215 ° C. From these results, it was found that the nanocolloid particles of the present invention are excellent in durability.

<Example 5>
[Dehydrogenation of alcohol on nano colloidal particle support system]
Nano colloidal particles using the silica gel of Example 3 in a glass flow reactor (length 180 mm, diameter 16 mm, holding a glass filter at the bottom) equipped with a flow path from a plunger pump for liquid chromatography at the bottom 3.1 g of support was placed. It was then plugged with glass wool and immersed in an oil bath. Subsequently, a vial bottle for collecting the liquid coming out from the upper part of the flow reactor was set. 1,4-butanediol was allowed to flow from the plunger pump to fill the flow reactor, the flow rate was set to 0.1 mL / min, and the oil bath was heated to 215 ° C. A thin, black and turbid reaction liquid flowed out during the temperature rise, but after reaching 215 ° C., a transparent liquid colored pale yellow flowed out. Moreover, generation | occurrence | production of the bubble was seen from the inside of a reactor.

  One hour after reaching 215 ° C., 1 mL fraction of the reaction solution was analyzed by gas chromatography and found to contain 7.2 wt% γ-butyrolactone. From this, it was found that the cyclization dehydrogenation reaction of 1,4-butanediol occurred using the PdZn nanocolloid particle carrier as a catalyst.

  Similarly, after 4 hours, it contained 9.7 wt% of γ-butyrolactone, and it was found that the PdZn nanoparticles functioned as a catalyst without desorption from the silica gel. After the reaction was stopped by cooling the oil bath, the plunger pump was stopped and the nanocolloid particle carrier was recovered from the flow reactor. Analysis of the nano colloidal particle carrier by ICP elemental analysis revealed that it contained Pd 1.27 wt% and Zn 0.58 wt%, which was almost the same as the value before use in the flow reaction. It was found that can be used.

<Example 6>
[Synthesis 2 of PdZn nano colloidal particles]
A PdZn nanocolloid particle dispersion was obtained by synthesizing in the same manner as in Example 1 except that 138 mg (0.455 mmol) of palladium acetylacetonate and 144 mg (0.545 mmol) of zinc acetylacetonate monohydrate were used. It was. When the metal concentration in the liquid was measured by ICP elemental analysis, Pd was 0.175 wt%, Zn was 0.102 wt%, and the composition of the alloy was Pd ₅₁ Zn ₄₉ .

<Example 7>
[Synthesis 3 of PdZn nano colloidal particles]
A PdZn nanocolloid particle dispersion was obtained by synthesizing in the same manner as in Example 1 except that 122 mg (0.4 mmol) of palladium acetylacetonate and 158 mg (0.6 mmol) of zinc acetylacetonate monohydrate were used. It was. When the metal concentration in the liquid was measured by ICP elemental analysis, Pd was 0.162 wt%, Zn was 0.139 wt%, and the composition of the alloy was Pd ₄₂ Zn ₅₇ .

<Example 8>
[Synthesis 4 of PdZn nano colloidal particles]
A PdZn nanocolloid particle dispersion was obtained by synthesizing in the same manner as in Example 1 except that 76 mg (0.25 mmol) of palladium acetylacetonate and 198 mg (0.75 mmol) of zinc acetylacetonate monohydrate were used. It was. When the metal concentration in the liquid was measured by ICP elemental analysis, Pd was 0.079 wt%, Zn was 0.097 wt%, and the composition of the alloy was Pd ₃₃ Zn ₆₇ .

<Example 9>
[Synthesis 5 of PdZn nanocolloidal particles]
Example except that 152 mg (0.5 mmol) of palladium acetylacetonate, 132 mg (0.5 mmol) of zinc acetylacetonate monohydrate, 0.064 mL (0.2 mmol) of oleic acid, and nitrogen gas were circulated. 1 to obtain a PdZn nanocolloid particle dispersion. When the metal concentration in the liquid was measured by ICP elemental analysis, the composition of the alloy was Pd ₅₂ Zn ₄₈ . When observed with a transmission electron microscope, the average particle size of the PdZn nanocolloid particles was 7.8 nm, and the standard deviation was 20%.

<Comparative Example 1>
PdZn colloidal nanoparticles were synthesized by the same method as Bronstein et al. [J. Catal. 196, 302 (2000)]. The polystyrene-vinylpyridine diblock polymer used did not become uniform because micelles were formed in the flask. When the crystal structure of the product was analyzed with a powder X-ray diffractometer (CuKα ray), it showed a main peak at 40.1 °. Moreover, another peak existed at 46.6 ° and appeared as a shoulder on the right side of the main peak. These peak positions coincided with the peak positions of the metal Pd and were different from the peak positions of the PdZn alloy.

  114.6 mg of the synthesized particles and 5 mL (56.6 mmol) of 1,4-butanediol were placed in a 25 mL round bottom flask, heated to 215 ° C. and maintained for 1 hour. When the reaction solution was partially extracted with a glass syringe, diluted with acetone and analyzed by gas chromatography, no peak of γ-butyrolactone appeared. From this, it was found that the nanocolloid particles synthesized by the technique of Bronstein etc. do not possess the cyclization dehydrogenation ability of 1,4-butanediol.

2 is a powder X-ray diffraction pattern of PdZn nanocolloid particles obtained in Example 1. FIG. 2 is a powder X-ray diffraction pattern of PdZn nanocolloid particles obtained in Comparative Example 1. FIG.

Claims (9)

  An alloy comprising an element selected from Group 10 of the periodic table (hereinafter referred to as “A”) and an element selected from Group 12 of the periodic table (hereinafter referred to as “B”), Nanocolloid particles having a particle size of 1 nm to 50 nm.   Nanocolloid particles according to claim 1, characterized in that the particle size distribution has a standard deviation of the particle size of 30% or less with respect to the average particle size.   The nanocolloid particles according to claim 1 or 2, wherein A is palladium and B is zinc. The nanocolloid particle according to any one of claims 1 to 3, which has a composition represented by the following general formula.
A _(100-X) B _X
(X represents a number of 30 to 80)   The nanocolloid particles according to any one of claims 1 to 4, wherein a coordinating organic molecule having a molecular weight of 15000 or less is bonded to the surface of the particles.   A nanocolloid carrier in which the nanocolloid particles according to any one of claims 1 to 5 are supported on a carrier.   A catalyst for a dehydrogenation reaction of an alcohol compound, comprising the nanocolloid particles according to claim 1 or the nanocolloid carrier according to claim 6.   A compound containing A in the molecular structure, a compound containing B in the molecular structure, a reducing agent, a coordinating organic molecule and a solvent are mixed to form a homogeneous solution, and then the homogeneous solution is heated, The method for producing nanocolloid particles according to any one of claims 1 to 5, wherein fine particles of alloy AB are produced, and then the surface of the fine particles is covered with a coordinating organic molecule.   A method for producing a carbonyl compound, wherein the alcohol compound is dehydrogenated using the nanocolloid particles according to any one of claims 1 to 5 or the nanocolloid carrier according to claim 6.