JPS6158401B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a carbon material made of carbon particles in which a metal or a metal compound is uniformly dispersed, and a method for producing the same. Carbon materials made of a mixture of metal or metal oxide and carbon powder have conventionally been used in toners, catalysts, and the like. Carbon materials made of this mixture are made by mixing carbon powder with a low specific gravity with metals such as iron powder with a high specific gravity, so it is impossible to obtain a uniformly dispersed mixture. Therefore, carbon materials made of such a mixture cannot be used as toners. However, there was a drawback that uniform printing was difficult. It is also known that carbon black is mixed with a metal salt and then thermally decomposed to deposit the metal on the surface of the carbon black for use as a catalyst. however,
This method has the disadvantage that the metal produced tends to aggregate on the surface, and because the metal is too active, it is easily oxidized and the catalytic activity decreases. The present invention has been made to solve these drawbacks, and involves heating a mixture or liquid material of a carbonizable organic compound and an organometallic compound to 350 to 900°C under a pressure of 1 to 3000 kg/ ^cm2 . This is based on the fact that, for the first time, a carbon material consisting of carbon particles in which a metal or a metal compound is uniformly dispersed can be obtained. To explain the structure of the present invention in more detail, carbonizable organic compounds, such as easily graphitized organic compounds such as styrene, anthracene, naphthalene, and vinyl chloride, which produce carbon by pressure heating, or divinylbenzene and paraterphenyl Carbonizable organic compounds made of polymerizable monomers such as non-graphitizable organic compounds such as biphenyl and phenol formaldehyde, specifically monomers such as styrene and divinylbenzene, or different types of carbonizable organic compounds. A combination of two or more organic compounds is used to form an organometallic compound, that is, Fe, Co,
More specifically, combinations of two or more types of polymerizable monomers containing transition metal elements such as Ni, Pt, and Rh include vinyl ferrocene monomers, vinyl nickelsene monomers, vinyl cobalt cene monomers, or organometallic compounds containing different metal elements. Mix the ingredients together to prepare a mixture. In this case, the blending ratio of the carbonizable organic compound and the organometallic compound can be arbitrarily selected depending on the purpose, but generally the molar ratio is 10:90 to 99.9:0.1, preferably 50:50 to
Mix 90:1. In addition, if both the carbonizable organic compound and the organometallic compound are solid at room temperature and normal pressure, they can be dissolved uniformly in a solvent such as toluene, benzene, or xylene, and then the solvent can be removed to form a mixture. When one is liquid, the other is dissolved therein to form a liquid. Then, the mixture or liquid substance is sealed in a metal container and heated at 350 to 900°C, preferably 400 to 800°C, for about 1 to 200 minutes under a pressure of 1 to 3000 kg/ ^cm2 , preferably 20 to 2000 kg/cm2 ^. Perform pressure heating. If both the carbonizable organic compound and the organometallic compound are polymerizable monomers, a more homogeneous product can be obtained by copolymerizing the mixture or liquid material before pressurizing and heating. This is preferable because it allows for Note that the atmosphere during pressurization and heating may be any of an inert gas atmosphere such as argon and helium, a reducing atmosphere such as CO and H ₂ , or a nitrogen atmosphere. Then, by pressurizing and heating, a carbon material in which metals or metal compounds are uniformly dispersed inside dense carbon particles is obtained, and the morphology of the produced carbon material depends on the pressurizing and heating conditions and the proportion of organometallic compounds. As the particles change, they change into spherical or hair-like shapes, or when individual particles are connected, they become polyhedral or porous. In either case, a carbon material can be obtained in which the metal or metal compound is uniformly dispersed within the carbon particles with a size of 20 Å to 500 Å. The type of metal compound in the carbon particles in this carbon material is influenced by the atmosphere during pressure heating and the type of organic compound that can be carbonized. For example, in an inert gas atmosphere or a reducing gas atmosphere, metal or metal carbide is generally formed. However, under a nitrogen atmosphere, metal nitrides may also be formed depending on the type of metal element and the pressure and heating conditions. In addition, by pressurizing and heating in the presence of water, water acts to break the carbon-carbon bonds of the raw material compound, changing the viscosity and volume fraction of the hydrocarbons produced by thermal decomposition, and changing the carbon-carbon bonds during the carbonization process. Since it affects the state, it becomes easy to control the shape of carbon.
In that case, metals or metal oxides are formed within the carbon particles. Furthermore, when vinylferrocene is used as an organometallic compound, the organic compound that can be carbonized is divinylbenzene, which produces cementite (Fe 3 C) when heated under pressure, whereas styrene produces cementite (Fe ₃ C).
metal is produced. When the carbon particles are spherical, the size of the carbon particles can range from about 200 Å to about 20 μm depending on the type and proportion of organic compounds that can be carbonized under pressure and heating conditions. Then, if necessary, the pressurized and heated product is heat-treated at 300 to 1000°C for about 1 hour in an oxygen-containing atmosphere, so that the generated carbon reacts with oxygen and evaporates as CO gas, creating a porous carbon material. Obtainable. For example, when a spherical carbon material in which magnetite is dispersed, obtained by pressurizing and heating in the coexistence of water, is heat-treated at a temperature of 800°C or less in an oxygen-containing atmosphere, it becomes porous with open pores communicating from the carbon particle surface to the inside. High quality magnetite-containing carbon spherical particles can be obtained. The reason why metals or metal compounds are uniformly dispersed and generated within carbon particles by pressurizing and heating carbonizable organic compounds and organometallic compounds is as follows.
Although it is not clear, it can be considered as follows. In other words, the decomposition of the raw material compound, the formation of carbon-carbon bonds, and the formation of carbon occur due to pressurized heating, but by pressurizing and heating both at the same time, carbon-carbon bonds are formed between the organic compound and the organometallic compound. It is considered that carbon particles containing uniformly dispersed metals or metal compounds are generated because carbonization occurs while generating and incorporating metal elements. Next, the reason for limiting the numerical range of the present invention is as follows:
If the pressure during pressure heating is lower than 1Kg/ ^cm2 ,
The yield of the carbon material obtained was poor, 3000Kg/cm ²
Higher pressures make the pressure vessel larger and more expensive, which is economically disadvantageous and industrially unfavorable. Further, at temperatures lower than 300°C, carbonization does not occur sufficiently, and at temperatures above 900°C, the properties of the product do not change significantly, although the heating equipment becomes expensive. Next, the present invention will be explained by examples. Example 1 Divinylbenzene or styrene as a carbonizable organic compound and monovinylferrocene, monovinylnitkelsene, or monovinylcobaltocene as an organometallic compound are weighed in the proportions shown in Table 1, dissolved in benzene, and then the benzene is evaporated. After removal, it was sealed in a gold capsule in an argon gas atmosphere, and copolymerized for 2 hours by heating to 300° C. under a pressure of 1000 kg/cm ² using a hydrothermal synthesizer. The copolymer was once taken out from the capsule, and then heated and pressurized again in the capsule under the atmosphere and pressure/heating conditions listed in Table 1 to obtain the carbon material of the present invention. As a comparative example, a carbon material was obtained by pressurizing and heating a mixture of divinylbenzene and iron chloride. The morphology of the carbon produced, the type of dispersed particles, the size and dispersion state, etc. of these carbon materials were compared and measured, and the results are shown in Table 1.
The form of the generated carbon was determined using a scanning electron microscope, the type of dispersed particles was determined using an X-ray diffraction device, the size of the dispersed particles,
The dispersion state was observed and measured using an electron microscope. FIG. 1 shows an electron micrograph of sample No. 2, and FIG. 2 shows an electron micrograph of the vicinity of the surface of the spherical carbon material in FIG. As is clear from Table 1 and Figure 2, the carbon material obtained by the method of the present invention has a metal or metal compound (corresponding to A in Figure 2) with a size of 200 Å or less uniformly contained in the carbon material. In contrast, in the comparative example, metallic iron particles had a size of 1000 Å or more and were nonuniformly aggregated on the carbon particle surface.

[Table] Example 2 A part of the carbon material of sample No. 7 of Example 1 was
Heat treatment was carried out in air at a temperature of 400°C for 2 hours.
This heat treatment resulted in a weight reduction of 10% by weight. As a result of comparative observation using a scanning electron microscope of the carbon materials before and after heat treatment, the size of the carbon particles was 8μ in each case, and no change in particle size was observed. Numerous pores were observed, forming porous spherical particles. In order to examine the catalytic performance of this porous spherical particle containing the metal nickel, we prepared a comparative sample in which nickel was supported on the surface of 8μ carbon particles consisting only of carbon. As a result of measuring the conversion rate of the mixed gas into methane, it was found that the conversion rate using the porous spherical carbon particles of the present invention was 95%, while the conversion rate was approximately 50% using the comparative sample. It was hot. As described above, the carbon material of the present invention has extremely fine metals or metal compounds uniformly dispersed inside carbon particles by heating a carbonizable organic compound and an organometallic compound under pressure. In addition, by heat treatment if necessary, a porous carbon material can be obtained, and the obtained carbon material can be used as a toner, a catalyst, or a magnetic material, and is extremely useful industrially. A carbon material and its manufacturing method.

[Brief explanation of the drawing]

Fig. 1 is a scanning electron micrograph of the iron-dispersed spherical carbon material of the present invention as Sample No. 2 of Example 1, and Fig. 2 is an electron micrograph showing the vicinity of the particle surface of the carbon material of the present invention of Fig. 1. be.

Claims (1)

[Claims] 1. A carbon material comprising carbon particles in which a metal or a metal compound is uniformly dispersed. 2. The carbon material according to claim 1, wherein the carbon particles are spherical. 3. The carbon material according to claim 1 or 2, wherein the metal element of the metal or metal compound is at least one selected from transition metals. 4. A carbon material characterized by heating a mixture or liquid material of a carbonizable organic compound and an organometallic compound, both of which are made of polymerizable monomers, to 350 to 900°C under a pressure of 1 to 3000 Kg/ ^cm2 . manufacturing method. 5. The method for producing a carbon material according to claim 4, wherein the pressurized and heated product is heat-treated in an oxygen-containing atmosphere. 6. The method for producing a carbon material according to claim 4, wherein the mixture or liquid material of a carbonizable organic compound and an organometallic compound is copolymerized before heating. 7 Claim 4, wherein the metal element of the organometallic compound is at least one selected from transition metals.
6. A method for producing a carbon material according to item 5, item 6, or item 6. 8. The method for producing a carbon material according to claim 6 or 7, wherein the carbonizable organic compound is at least one of divinylbenzene or styrene, and the organometallic compound is a vinylferrocene monomer. 9. The method for producing a carbon material according to any one of claims 4 to 8, wherein the pressurized heating is performed in the presence of water.