JPH0250043B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a ternary residual compound having homogeneous and stable compositional properties consisting of a transition metal, graphite and an organic molecule.

Graphite crystal is manufactured by stacking regular hexagonal network planes three-dimensionally with an interlayer distance of 3.35 Å due to covalent bonds of carbon atoms, and the layer planes are bonded by weak van der Waals forces. Various graphite intercalation compounds are produced by allowing ions, atoms, etc. to penetrate between the layers under appropriate conditions. A variety of substances are known to form graphite intercalation compounds, such as halogen elements, alkali metals, inorganic acids, and chlorides and fluorides of various metals, but many of the intercalation compounds obtained are It is extremely unstable and has a tendency to rapidly decompose and change in quality. Among these, graphite intercalation compounds of transition metals are
Since it is expected to have unique physical properties compared to those created by other chemical species, many examples of research have been conducted to date.
However, it is either impossible to produce the product using the production techniques known so far, or there are objections to the product, and no established method for synthesis has been found at present. For this reason, although it is promising in terms of physical properties, it has not yet reached a state where it can fully demonstrate its additional functions.

The present invention uses a specific reaction method to generate a ternary intercalation compound in which transition metals and organic molecules such as THF or DME are homogeneously interposed between graphite layers, and furthermore, most of the transition metals and organic molecules are By performing a stabilization treatment while remaining between the graphite layers, we succeeded in converting it into a ternary residual compound with an extremely stable form and unique physical properties in the air, leading to its development.

That is, the method for producing a transition metal-graphite-organic molecule-based ternary residual compound provided by the present invention is to react a potassium-graphite intercalation compound (CnK) obtained by reacting graphite and potassium with tetrahydrofuran (THF) or Once the interlayer of the ternary system is formed by a substitution reaction in contact with ions of a transition metal selected from iron, cobalt, nickel, manganese, copper, molybdenum, chromium, zinc, ruthenium, palladium, and platinum in dimethoxyethane (DME), The structural feature is that a compound is generated, and then the intercalation compound is immersed in water to perform a stabilization treatment.

The synthesis of potassium-graphite intercalation compound (CnK) is
There are two methods: a method in which graphite and potassium are stirred and mixed while being heated to approximately 200℃ in an argon stream, or a method in which potassium vapor is uniformly brought into contact with heated graphite in a vacuum or an argon atmosphere to cause a vapor-solid reaction. , purer and lower stage products can be obtained in the latter method.

The generated CnK is subjected to a substitution reaction with a transition metal in THF or DME that has been sufficiently dehydrated by distillation purification. Transition metals as chemical species include iron, cobalt,
Nickel, manganese, copper, molybdenum, chromium,
It is selected from zinc, ruthenium, palladium and platinum and is used in the form of salts, especially chlorides. However, if these salts contain water,
It decomposes CnK in THF or DME, inhibits normal reactions, and significantly reduces the production yield of transition metal-graphite-organic molecular intercalation compounds. Therefore, in order to carry out the substitution reaction effectively, it is an important condition to use an anhydrous metal salt.

Taking THF and anhydrous chloride of a transition metal as an example, the substitution reaction proceeds according to the following reaction formula.

CnK+MClnTHF ---→ MCn(THF)p+nKCl where M is a transition metal, THF is a tetrahydrofuran molecule, and n (n〓8) and p (0<p3) are series numbers.

In order to efficiently complete the above substitution reaction,
It is effective to gradually add, while stirring, a THF or DME solution in which an anhydrous salt of a transition metal has been fused in advance to THF or DME to which CnK has been added. Also, the amount of transition metal anhydride added is
It is desirable to use an excess amount relative to CnK, and to maintain the reaction atmosphere in an inert gas such as argon or nitrogen.

The product obtained by the substitution reaction has the form of a ternary intercalation compound in which transition metal and THF or DME molecules are homogeneously intercalated and dispersed between graphite interlayers, but it is unstable and rapidly decomposes and deteriorates when exposed to air. exhibits physical properties.

The ternary intercalation compound is then stabilized by immersion in water. Through this treatment, the intercalation compound undergoes permanent decomposition while retaining its compositional form as it is, and is converted into a stable residual ternary compound consisting of transition metal-graphite-organic molecules. The remaining compounds after the treatment are further washed with water to dissolve and remove most of the remaining potassium components and potassium chloride precipitated by the substitution reaction.

The ternary residual compound produced through the above process has a layered structure in which most of the transition metals and organic molecules such as THF or DME remain between the graphite layers, and are no longer susceptible to decomposition and alteration in the air. It has extremely stable physical properties. This is thought to be based on a unique manufacturing form in which transition metals are held in a stable state between graphite layers by organic molecules coexisting with them, and due to this structure, magnetic property when iron, cobalt, etc. are used as chemical species. , or unique physical properties such as expansion changes (surface area increase effect) due to the release of organic molecules upon heating.

As described above, according to the present invention, it is possible to easily produce a ternary residual compound that has effective properties applicable to a wide range of applications and is extremely stable in air, which is expected as a transition metal-graphite intercalation compound. Profit is brought.

Hereinafter, the present invention will be explained based on examples.

Example 1 Natural graphite powder [Nippon Graphite Industries Co., Ltd.
Co., Ltd.] and a metal potassium piece with the oxidized surface removed [Kanto Kagaku Co., Ltd., reagent grade 1] separated and charged.
After sealing, the natural graphite powder was periodically stirred while maintaining the reaction tube at a temperature of 250 to 255°C. During the heating process, metallic potassium was melted and vaporized, and reacted with natural graphite powder in the vapor state. The reaction product is a powder with a chemical composition of C ₈ K, with X-ray diffraction results of 5.37 Å and
It was confirmed that this was a pure first stage potassium-graphite intercalation compound showing a maximum peak at a position of 2.67 Å. FIG. 1 shows the X-ray diffraction pattern.

Pour 10 ml of THF that has been sufficiently dehydrated and distilled into a side-armed flask, and add 2.0439 (8.97 mmol) of the above C ₈ K to it.
was added and soaked. Separately, 2.2116 g ( _17.04 m
mol) was added to dehydrated and distilled THF, and a portion was dissolved.

Then, after replacing the atmosphere in the flask with side arms with argon gas, CoCl ₂ was dissolved while stirring.
The THF solution was added dropwise over 1 hour. At the beginning of the application, the blue color of the THF solution disappeared immediately, and the color of C ₈ K changed from gold to black. Subsequently, the mixed solution in the flask was stirred for 48 hours to complete the substitution reaction. A black flaky powder and white crystals of potassium chloride precipitated at the bottom of the flask.

For comparison, 2.0439 g (15.1 mmol) of C ₈ K, 3.6768 g (15.5 mmol) of hydrated cobalt chloride (CoCl ₂ 6H ₂ O)
When we conducted a production experiment using the same method under quantitative conditions of (mol), we found that C ₈ K decomposed due to the water content of cobalt chloride before the substitution reaction between potassium and cobalt, resulting in the formation of black flake-like powder. was hardly recognized.

As a result of X-ray diffraction of the obtained flaky powder product, clear peaks appeared at positions such as 8.9 Å and 4.45 Å. Figure 2 shows the X-ray diffraction pattern, which is significantly different from Figure 1 (C ₈ K diffraction pattern) and very similar to the KC ₂₄ (THF) ₂ intercalation compound (first stage). It was in the form of
This indicates that THF molecules (5.55 Å) form the spacing between graphite layers (planar spacing 5.55 Å + 3.35 Å = 8.9 Å), and since it has a high degree of magnetism in THF solution, cobalt and THF It was confirmed that this was a cobalt-graphite-THF intercalation compound [CoC ₂₄ (THF) ₂ ] in which molecules were homogeneously interposed between graphite layers.

Then, the above-generated ternary intercalation compound was separated from THF in a nitrogen stream, immediately immersed in water for stabilization treatment, and then filtered and washed in the air repeatedly. The processed material is kept at 80℃ in the air.
It was dried and stored at a temperature of Through stabilization treatment, the ternary intercalation compound was converted into an extremely stable flake-like residual compound that did not change in quality during filtration, water washing, or storage.

FIG. 3 shows the X-ray diffraction pattern measured for the residual compound obtained. This figure exhibits the same pattern as graphite except that each diffraction line is broad, and in many cases, lines other than the 00l diffraction line are very weak or barely visible. Furthermore, although the 00l diffraction line sometimes has a tail toward the lower angle side, no diffraction line corresponding to metallic cobalt or other cobalt compounds was observed.

FIG. 4 shows the results of compositional analysis using an X-ray microphone analyzer. Although the shape confirms that a large amount of cobalt is present in the remaining compound, surface analysis reveals that its distribution is homogeneous and dispersed without local aggregation. Note that most of the potassium chloride was removed by washing with water, and only a small amount of potassium and chlorine remained.

The resulting residual compound is cobalt-graphite-
It is a ternary material that maintains the compositional properties of a THF-based intercalation compound, and is a magnetic material that exhibits an S-shaped hysteresis loop magnetic curve. Furthermore, when this was heat-treated, THF molecules volatilized from between the graphite layers at temperatures above 150°C, causing a rapid swelling phenomenon, and it had the unique physical property of losing magnetism at this stage.

Similarly to the above example, iron, nickel, manganese,
When experiments were conducted using anhydrous chlorides of copper, molybdenum, chromium, and zinc, ternary residual compounds consisting of benign transition metal-graphite-organic (THF) molecules were obtained for each chemical species. Ta.

Example 2 C ₈ K synthesized by the same method as Example 1 was added to dehydrated and distilled DME, and a DME solution of anhydrous ruthenium chloride (RuCl ₃ ) was added dropwise with stirring.
Subsequently, the mixture was stirred for 8 hours to complete the substitution reaction. The substitution reaction produced a ternary intercalation compound of ruthenium-graphite-DME molecules.

The above three-component intercalation compound was stabilized by immersing it in water without contacting it with air, followed by repeated filtering and washing in the air.

The obtained product is Ruthenium-Graphite-DME
The residual compound had a homogeneous composition and had extremely stable physical properties in air and water.
When this ternary residual compound was heated to 150°C,
DME molecules devolatilized and rapidly swelled, making the product suitable for catalytic applications.

As a result of performing the same reaction stabilization treatment as described above using anhydrous chlorides of palladium and platinum, a homogeneously stable ternary residual compound of a transition metal-organic (DME) molecular system was obtained.

[Brief explanation of drawings]

Fig. 1 shows the X-ray diffraction pattern of the potassium-graphite intercalation compound which is the starting material of the present invention, and Fig. 2 shows the ternary system (cobalt-graphite-
The X-ray diffraction pattern of the THF molecule) intercalation compound, Figure 3 shows the cobalt-graphite-
This is an X-ray diffraction pattern of a THF-based ternary residual compound. FIG. 4 shows a compositional analysis pattern of the above-mentioned cobalt-graphite-THF ternary residual compound using an X-ray microprobe analyzer.

Claims (1)

[Claims] 1 A potassium-graphite intercalation compound (CnK) obtained by reacting graphite and potassium is mixed with iron, cobalt, nickel, manganese, copper, and molybdenum in tetrahydrofuran (THF) or dimethoxyethane (DME). , contact with a transition metal selected from chromium, zinc, ruthenium, palladium, and platinum to generate a ternary intercalation compound through a substitution reaction, and then stabilize the intercalation compound by immersing it in water. A method for producing a ternary residual compound consisting of a transition metal, graphite, and an organic molecule, characterized by the following. 2 Gradually add a solution of anhydrous transition metal chloride in tetrahydrofuran (THF) or dimethoxyethane (DME) to which potassium-graphite intercalation compound (CnK) has been added while stirring. A method for producing a ternary residual compound comprising a transition metal-graphite-organic molecule according to claim 1, which comprises adding the ternary residual compound to a molecule to complete the substitution reaction.