JPH0597416A - Carbon cluster - Google Patents

Abstract

PURPOSE:To produce a high purity carbon cluster with excellent productivity by heating a condensed polycyclic arom. compd. contg. 5- and 6-membered rings or a mixture of a 5-membered arom. compd. with a 6-membered arom. compd. to a specified temp. in an inert gaseous atmosphere. CONSTITUTION:A condensed polycyclic arom. compd. contg. 5- and 6-membered rings such as acenaphthene or acenaphthylene or a mixture of a 5membered arom. compd. such as cyclopentadiene or dicyclopentadiene with a 6-membered arom. compd. such as naphthalene or anthracene in (1:100) to (100:1) ratio is evaporated by heating in an inert atmosphere of Ar, etc., and the resulting vapor is heated to 500-2,500 deg.C by irradiation with IR, electron beams, laser beams, etc. A very high purity carbon cluster is produced with high production efficiency.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a carbon material.

[0002]

2. Description of the Related Art Amorphous carbon, graphite, diamond and the like have been known as carbon materials. on the other hand,
It has recently been reported that carbon clusters composed of carbon atoms 60 and 70 are generated by arc plasma decomposition of carbon and laser beam irradiation (Nature, 347, 354).
(1990)). The carbon clusters generated here have a spherical structure and various applications such as lubricants, conductive materials, superconducting materials, and synthetic raw materials are considered. However, the carbon decomposition by the above-mentioned technique requires a high temperature, so that the production rate is low, and the yield of these carbon clusters is as low as about 10% of the product. Further, there is a problem that purification of carbon clusters is complicated because of low yield.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to obtain high-purity carbon clusters synthesized in high yield and at high speed, and to establish a highly efficient synthesis method thereof.

[0004]

As a result of intensive studies to obtain a carbon cluster with high efficiency, the present inventor found the carbon cluster of the present invention and a method for producing the same, and completed the present invention. That is, the present invention relates to a condensed polycyclic aromatic compound containing a 5-membered ring and a 6-membered ring, or a 5-membered aromatic compound
It is a carbon cluster produced by heating a gas or vapor of a mixture of membered-ring aromatic compounds at a temperature of 500 ° C. or higher and lower than 2500 ° C. in an inert atmosphere.

The composition of the carbon cluster of the present invention can be investigated by elemental analysis and mass spectrometry. A hydrogen / carbon composition ratio can be determined by elemental analysis, and the carbon cluster of the present invention has a composition ratio of 0.1 or less. Further, the carbon number of the cluster can be obtained by mass spectrometry. The carbon cluster of the present invention is a molecule substantially composed of carbon having 20 (mass number 240) or more and 800 (mass number 9600) or less carbon atoms. Although the number of carbon atoms varies depending on the manufacturing conditions, it cannot be generally stated, but in the present invention, carbon clusters having 30 (mass number 360) or more and 200 (mass number 2400) or less are obtained in high yield. The carbon cluster of the present invention has a structure different from that of conventional carbon materials such as amorphous carbon, graphite and diamond. This structure can be examined by X-ray diffraction method, solubility, infrared absorption spectrum, NMR, electron microscope, tunnel microscope and the like.
For example, in the X-ray diffraction method, the carbon cluster of the present invention has a structure with an interplanar distance of 8 angstroms or more, which is different from the graphite structure (lattice constant 6.9 angstrom, 2.5 angstrom) and diamond structure (lattice constant 3.6 angstrom). I understand. Further, the carbon cluster of the present invention is characterized by high solubility in various solvents, which is different from the fact that conventional amorphous carbon, graphite and diamond are not dissolved in solvents. Examples of the solvent include carbon disulfide, benzene, toluene, xylene, chloroform and dichloromethane. The product of the present invention is characterized by containing a large amount of components soluble in these solvents, and the content rate thereof reaches 30% or more of the product. This suggests that a large amount of carbon clusters, which are solvent-soluble components, are generated. These are preferred because they can be easily separated and an efficient solvent extraction method can be used. Further, in the arc plasma decomposition method of graphite and laser light irradiation method, which are conventionally known methods for synthesizing carbon clusters, carbon clusters having carbon numbers of 60 and 70 are selectively generated. However, in the carbon cluster produced in the present invention, the carbon number of the carbon cluster can be changed by the aromatic hydrocarbon supplied.

Next, a method for producing a carbon cluster of the present invention will be described. The carbon cluster of the present invention is a condensed polycyclic aromatic compound containing a 5-membered ring and a 6-membered ring as a raw material, or
A carbon cluster is synthesized by using a mixture of a six-membered ring aromatic compound and a six-membered ring aromatic compound and heating the gas or vapor of this raw material at a temperature of 500 ° C or higher and lower than 2500 ° C in an inert gas atmosphere. is there.

Examples of the fused polycyclic aromatic compound containing a 5-membered ring and a 6-membered ring used here include acenaphthene, acenaphthylene, azulene, benzofluorene, bifluorenylidene, cyclophenanthrene, decacyclene, fluoranthene, fluorene. , Phenylanthracene, tetraphenylcyclopentadienone, clopentazyl,
It is also possible to use a mixture of corannulene, benzofuran, benzimidazole, indole, benzthiazole, thionaphthene, dibenzfuran and derivatives thereof, and a mixture of a 5-membered aromatic compound and a 6-membered aromatic compound. As the 5-membered ring aromatic compound, cyclopentadiene, dicyclopentadiene, pyrrole, bipyrrole, terpyrrole, oligopyrrole, thiophene, bithiophene, terthiophene, oligothiophene, pyrazole,
Examples thereof include imidazole, oxadiazole, thiadiazole, furan, oxazole, triazole and thiazole. As a 6-membered ring aromatic compound mixed with these 5-membered ring aromatic compounds, naphthalene, anthracene, naphthacene, pentacene, hexacene, heptacene, phenanthrene, biphenylene, acenaphthene,
Pyrene, chrysene, benzophenanthrene, benzanthracene, perylene, benzoperylene, dibenzanthracene, dibenzphenanthrene, antoanthrone,
Coronene, hexachrysene, dibenzoperylene, benzobisanthrone, terylene, diphenylnaphthacene, acedianthrone, ovalen, dibenzocoronene, diperinaphthylene, quaterrylene, methylcholanthrene, phenylanthracene, pyranthrone, tetraphenylcyclopentadyl, biphenylene, terphenylene And so on. The mixing ratio of the 5-membered aromatic compound and the 6-membered aromatic compound varies depending on the kind of the compound, but is 1:
A range of 100 to 100: 1 is preferred. These aromatic compounds are brought into a gas or vapor state in an inert gas atmosphere. As this method, for example, a method in which an aromatic compound is made into a gas or vapor by heating evaporation, reduced pressure evaporation, vaporization with a carrier gas, etc. is used. be able to. Here, the inert gas atmosphere is a state in which the partial pressure of an active gas such as oxygen or nitric oxide is low or zero, and is, for example, an inert gas atmosphere such as nitrogen, argon, xenon, or helium, or a reduced pressure or a vacuum atmosphere. is there.

Then, heating the gas / vapor of the condensed polycyclic aromatic compound containing a 5-membered ring and a 6-membered ring or the mixture of the 5-membered aromatic compound and the 6-membered aromatic compound in an inert gas atmosphere. To synthesize a carbon cluster. Examples of the heating method include irradiation with radiant energy such as infrared rays, visible rays, electron beams, radiation, X-rays, and laser beams. A method of heating by applying external energy such as discharge plasma or high frequency heating can also be used. The heating temperature is not limited because it varies depending on the holding time (reaction time) of the raw material at that temperature and the kind of the raw material, but is preferably in the temperature range of 500 ° C. or higher and lower than 2500 ° C. for high efficiency synthesis. This temperature is 500
If the temperature is lower than 0 ° C, the thermal decomposition of the raw material is insufficient, resulting in a low yield of carbon clusters. If the temperature is 2500 ° C or higher, carbon having a graphite structure is easily generated and a large amount of energy is consumed, which is not preferable.

Since the product obtained in the present invention contains a large amount of carbon cluster components soluble in the solvent, the solvent extraction operation can be simplified or omitted when the soluble components are used. The carbon cluster of the present invention can be applied to various applications such as a lubricant, a conductive material, a superconducting material, and a synthetic raw material, and can be processed into a bulk form, a thin film form, a composite material, and the like to be a functional material on an industrial scale. It is useful.

In the conventional arc plasma method using graphite and the laser method, the generation rate is low. It is conceivable that a large amount of energy is required to generate carbon clusters because the raw material carbon has a high melting point of 3000 ° C. or higher. Since the raw material used in the production of the present invention has a low melting point and a high vapor pressure, carbon clusters can be synthesized at a relatively low temperature as compared with these conventional methods. The structure of the condensed polycyclic aromatic compound containing a 5-membered ring and a 6-membered ring as a raw material is a part of the carbon cluster constitutional structure, and the mixture of the 5-membered aromatic compound and the 6-membered aromatic compound is a carbon cluster- It is considered that the carbon clusters can be synthesized with high efficiency because it is a constituent substance of Furthermore, since the method of the present invention is simple, mass production of synthesis is easy. From these facts, the carbon cluster production method of the present invention is industrially useful.

[0011]

EXAMPLES Next, the present invention will be described in more detail with reference to Examples and Reference Examples.

[0012]

Example 1 1 g of decacyclene was put into an alumina boat (100 mm in length) and charged in a tubular quartz glass reaction vessel (30 mm diameter electric furnace core tube), and then a nitrogen gas flow of 500 ml / min. The atmosphere was replaced with a flow rate to make an inert atmosphere. Next, the reaction vessel was loaded into an electric furnace while flowing a nitrogen gas stream, and a part of the reaction vessel was heated and maintained at a temperature of 900 ° C. At the beginning of heating, the alumina boat part was placed outside the electric furnace, and then the reaction vessel was slid to heat the alumina boat from one side to evaporate decacyclene, and the vapor was heated in the electric furnace. At this time, the moving speed of the reaction container (quartz glass tube) was about 20 mm / min. Here, the reaction heating time was 5 minutes. The hot steam was introduced into a recovery container outside the reaction container with a nitrogen stream to obtain a product. About 700 mg of black powder product was obtained in the recovery container, and about 200 mg of black powder product was obtained on the tube wall of the reaction container.
Elemental analysis result of black powder C / H / 0 = 100 / 0.2
/0.1 (stoichiometry) and the product was found to consist essentially of carbon only. This powder 70
After dissolving and extracting 0 mg in dichloromethane, the solvent was distilled off from this solution in a reduced pressure atmosphere to obtain 500 mg of a black solid (yield of solvent-soluble component: 71%). As a result of mass spectrometric measurement of the black powder obtained here, a peak was observed in the region of carbon number 30 (mass number 360) to 800 (mass number 9600), and particularly from carbon number 40 (mass number 480) to 20.
The peak in the region of 0 (mass number 2400) was strong. Among these, the peak having 60 carbon atoms was the largest. When the structure of the solvent-extracted black solid was evaluated by a powder X-ray diffraction method, a diffraction pee with an interplanar distance of 10 angstrom was observed.

[0013]

Example 2 In the same manner as in Example 1, decacyclene 1 g was heated at 800 ° C. in an argon stream to obtain about 920 mg of a blackish brown powder product. As a result of elemental analysis of this product,
C / H / O = 100 / 1.0 / 0.1 (stoichiometric ratio). After extracting 500 mg of this powder with a solvent of carbon disulfide to extract a solvent-soluble component, the solution was distilled off under reduced pressure to obtain 420 mg of a blackish brown solid (yield of soluble content: 84%). As a result of mass spectrometric measurement of the blackish brown powder, a peak was observed in the region of 30 to 800 in terms of carbon number, and a peak in the region of 32 to 200 carbon was particularly strong.

[0014]

Example 3 As in Example 1, 1 g of acenaphthylene
Is heated at a temperature of 900 ° C in a nitrogen stream to give a black powder of about 9
Obtained 00 mg. Elemental analysis result of this black powder C / H
/O=100/0.5/0.2 (stoichiometric ratio). After solvent extraction of 500 mg of black powder with toluene,
The solvent was distilled off under reduced pressure to obtain 450 mg of a black solid (yield of soluble component: 90%). As a result of mass spectrometric measurement of the black powder obtained here, peaks were observed in the region of 30 to 800 carbon atoms, and peaks in the region of 50 to 200 carbon atoms were particularly strong.

[0015]

Example 4 Using the same reactor as in Example 1, 1 g of fluoranthene was loaded into a reaction vessel, and argon gas was added to 1 g.
The outlet of the reaction vessel was evacuated by a rotary pump while flowing at a rate of milliliter / minute, and the pressure inside the reaction vessel was maintained at 50 Torr. Then, the reaction vessel was heated at a temperature of 1100 ° C., and the same operation as in Example 1 was performed. When a trap was installed in front of the inlet of the rotary pump and cooled with dry ice / methanol, the reaction time of 5 minutes was about 700
mg of black product was recovered. In addition, about 200 mg of black powder was obtained from the wall of the reaction vessel. As a result of elemental analysis of the obtained black powder, C / H / O = 100 / 0.1 /
It was 0.04 (stoichiometric ratio). Black powder 500mg
Was subjected to solvent extraction with toluene, and the solvent was distilled off under reduced pressure to obtain 380 mg of a black solid (yield of soluble component: 76
%). As a result of mass spectrometric measurement of the black powder obtained here, a peak was observed in the region of 30 to 800 carbon atoms,
The peak in the region having 50 to 200 carbon atoms was particularly strong.

[0016]

Example 5 Using the same reaction vessel as in Example 1, 1 g of acenaphthene was charged into a platinum crucible and heated to 900 ° C. while supplying nitrogen gas at a rate of 1 liter / minute for synthesis. During the reaction, the exhaust containing the product was collected by a liquid nitrogen trap. After completion of the reaction, nitrogen in the trap was vaporized, and 600 mg of black powder was recovered. In addition, 170 mg of black powder produced was confirmed in the reaction vessel and was also collected. The obtained black powder (770 mg) was subjected to solvent extraction with chloroform to obtain 750 mg of a black solid (yield of soluble component: 97%). As a result of elemental analysis of the extracted black solid, C / H / O = 100 / 0.3 / 0.05
(Stoichiometric ratio). As a result of mass spectrometric measurement, peaks of 40 to 120 carbon clusters in terms of carbon number were observed.

[0017]

Example 6 A platinum crucible was filled with 1 g of anthracene and charged in the same reaction vessel as in Example 1. On the other hand, nitrogen gas was bubbled into dicyclopentadiene heated to 50 ° C. at a rate of 1 liter / minute to generate dicyclopentadiene vapor, and the gas was supplied to a reaction vessel at 900 ° C.
Synthesis was carried out by heating to ℃. During the reaction, the exhaust containing the product was collected by a liquid nitrogen trap. After completion of the reaction, when nitrogen in the trap was vaporized, about 800 mg of black powder was recovered. It was also found that about 100 mg of black powder was produced in the reaction vessel. Obtained black powder (50
(0 mg) was subjected to solvent extraction with chloroform to give 350
mg of black solid was obtained (yield of soluble component 70%). As a result of elemental analysis of the black solid after extraction, C / H / O = 100 /
It was 0.4 / 0.05 (stoichiometric ratio). The result of mass spectrometric measurement is 40 to 120 in terms of carbon number.
Carbon cluster peaks were observed

[0018]

[Comparative Example] High-purity carbon (atomic grade, made by Nippon Carbon) was attached to the arc electrode and the crucible using a vacuum arc furnace (made by Daia Vacuum), and the atmosphere pressure was 1 with helium gas.
After holding at 00 Torr, an alternating current was passed between the electrode and the crucible to generate arc plasma to heat the carbon.
After holding the arc plasma for 5 minutes, about 50 mg of soot-like product was obtained inside the arc furnace. As a result of the elemental analysis of this soot,
C / H / O = 100 / 0.2 / 0.1 (stoichiometric ratio). Next, 25 mg of soot was subjected to solvent extraction with toluene, and a solvent-soluble component was taken out. As a result, 3 mg of a black solid was obtained (yield of soluble content: 12%). As a result of mass spectrometric measurement of soot, a weak peak was observed in the region of 60 to 500 carbon atoms, and among them, the peaks of 60 and 70 carbon atoms were relatively strong.

[0019]

Since the carbon cluster of the present invention contains a large amount of a solvent-soluble component, the purification step can be simplified or omitted when using this component. Further, it is possible to obtain a carbon cluster of high purity, which is simpler, more productive and more efficient than the conventional production method.

[Brief description of drawings]

FIG. 1 is a mass spectrometric spectrum of carbon clusters produced in Example 1.

Claims (1)

[Claims] 1. A gas or vapor of a condensed polycyclic aromatic compound containing a 5-membered ring and a 6-membered ring or a mixture of a 5-membered aromatic compound and a 6-membered aromatic compound in an inert atmosphere at 500 ° C.
Carbon clusters produced by heating at a temperature above 2500 ° C.