JPH08268705A - Production of fullerene and device therefor - Google Patents

Abstract

PURPOSE: To provide an inexpensive method and device for continuously and stably synthesizing fullerene from a carbonaceous material by an arc-discharge process in good yield and in large quantities for a long time while sufficiently excluding the factors such as oxygen, moisture, etc., inhibiting the synthesis of fullerene. CONSTITUTION: A long-sized and flexible carbonaceous material 2 is arranged in the carbonaceous raw material feeder 1 such as creel and bobbin set in a treating chamber 6. The chamber 6 is transiently evacuated to a super-high vacuum of <=10<-2> mmHg to exclude oxygen, moisture, etc. An inert gas is then introduced into the chamber 6 to adjust the pressure in the chamber 6 to 5-500-mmHg. The atmosphere is maintained, the carbonaceous material 2 is continuously supplied closely to the counter electrode 4 set in the chamber 6, and a power is impressed between the material as an electrode and the counter electrode to generate an arc discharge. As fullerene is scattered, the fullerene is recovered from the soot accumulated in a soot receiver 5 surrounding the counter electrode 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fullerene manufacturing method and a manufacturing apparatus therefor, which employs an arc discharge method.
The present invention relates to a fullerene production method and a fullerene production apparatus capable of continuously producing a large amount of fullerenes stably from a carbonaceous raw material for a long time.

[0002]

2. Description of the Related Art Fullerene is a general term for spherical molecules composed of only carbon atoms. For example, 60 carbon atoms are arranged at each vertex of a soccer ball so that it can be described as a "soccer ball-like molecule". It is known that they are bonded to each other to form a hollow spherical molecule.

Since the existence of fullerenes was confirmed in 1985, various synthetic methods have been studied. A carbonaceous raw material typified by natural graphite is used as the raw material, and it is said that the carbonaceous raw material is decomposed and sublimated by heating at a high temperature of 3000 ° C. or higher to form atomic carbon, and these are recombined to form fullerene. As a method for high temperature heating in the production of fullerenes from carbonaceous raw materials, many proposals have been conventionally made by laser ablation method, resistance heating method, high frequency induction heating method, arc discharge method or a combination thereof. .

Among the fullerene production methods, the fullerene production method utilizing high temperature by the arc discharge method is to obtain a high temperature of 3000 ° C. or higher in a short time by local arc discharge between electrodes in an inert gas atmosphere. It is possible to synthesize fullerenes from carbonaceous raw materials with a relatively simple apparatus, and the total yield from carbonaceous raw materials is 1% or more, which is higher than other methods. For example, many proposals have been made as disclosed in Japanese Patent Laid-Open No. 5-502213 and Japanese Patent Laid-Open No. 5-116925.

[0005]

Problems to be Solved by the Invention
Japanese Laid-Open Patent Publication No. 213 discloses a basic technique for producing fullerene by an arc discharge method performed in an evacuated processing chamber at a pressure of about 50 to 400 torr below atmospheric pressure. However, according to the description of the publication, it is clarified that a graphite rod of a short length (about 1 cm in length) having a diameter of 0.25 inch is generally used as a carbonaceous raw material.
Therefore, since the carbonaceous material described in the publication is short, the carbonaceous material is continuously processed without breaking the depressurization condition in the processing chamber, that is, without returning to the atmospheric pressure, and a large amount of fullerene is obtained. Can't get

On the assumption that an attempt was made to expand this method to produce fullerenes in large quantities, for example, even if the carbonaceous raw material is replaced with a graphite rod of short length to long length, the same carbonaceous raw material is produced. Since it is a rigid long graphite rod, there is a problem that a large processing chamber corresponding to the size of the carbonaceous raw material is needed to accommodate the carbonaceous raw material, which is a cost disadvantage. . In addition, even if the processing chamber is enlarged and a long graphite rod is used as a carbonaceous raw material for a large amount of arc discharge treatment, a deposit made of a graphite substance containing nanotubes that grow by accumulating on the counter electrode. Since the discharge becomes unstable, the discharge current and the like fluctuate, and thus it is difficult to stably produce fullerene from a carbonaceous raw material, and as a result, the yield of fullerene is reduced, which is not preferable.

Further, in Japanese Patent Laid-Open No. 5-116925, a long carbon fiber wire is used as a carbonaceous raw material, and the carbonaceous raw material is continuously supplied to carry out arc discharge treatment to produce fullerenes. A manufacturing method is shown, and it is said that this method makes it possible to obtain fullerenes in large quantities. However, in the method described in the publication, since a long carbon fiber wire is installed outside the processing chamber and is introduced into the processing chamber from there, oxygen from the outside air in the processing chamber is introduced into the processing chamber at the carbon fiber wire inlet. Leakage such as intrusion of air is likely to occur, or oxygen or moisture remaining on the surface of the carbon fiber bundle or contained in the space may be entrained in the processing chamber. Therefore, in the method described in the publication, However, there is a problem in that components that inhibit fullerene synthesis, such as oxygen and water, cannot be sufficiently removed from the processing chamber, and the synthesis yield of fullerenes cannot be increased due to the influence of these components.

Further, in the method described in the above publication, when the carbon fiber wire is energized and discharged, the carbon fiber wire is fed toward the counter electrode in the lateral or upward direction. Due to problems such as defects and wire breakage, there is a high probability that the carbon fiber wire will hang down due to its own weight and come into contact with the wall surface of the processing chamber to cause electric leakage, insulation failure, etc.

Therefore, in order to solve such a problem, the present invention sufficiently eliminates the factors that inhibit the synthesis of fullerenes such as oxygen and water when synthesizing fullerenes from a carbonaceous raw material by the arc discharge method. It is possible to produce a fullerene in a large amount continuously from a carbonaceous raw material stably for a long time, and further, a fullerene synthesis yield is good, and an inexpensive production method and its production apparatus are provided. And

[0010]

In order to solve the above-mentioned problems, the method for producing fullerene which can be continuously produced for a long time according to the present invention has a long and flexible carbonaceous raw material arranged in a processing chamber. Then, (2) the inside of the processing chamber is once brought to an ultrahigh vacuum of 10 ^-2 mmHg or less, (3) an inert gas is introduced into the processing chamber to adjust the pressure in the processing chamber to 5 mmHg to 500 mmHg, (4) The carbonaceous raw material is continuously supplied so as to approach the counter electrode installed in the processing chamber, and the carbonaceous raw material is used as an electrode to apply electric power between both electrodes to cause an arc discharge to produce a carbonaceous material. It is characterized in that fullerene is produced from raw materials.

The fullerene production apparatus of the present invention, which can be continuously produced for a long time, includes (1) a carbonaceous raw material supply device capable of arranging and supplying a long flexible carbonaceous raw material,
A transport device that can guide the carbonaceous raw material to any position on the counter electrode, the rotatable counter electrode that is installed so as to face the tip of the carbonaceous raw material, and a soot receiver that is installed around the counter electrode. A vacuum device capable of removing oxygen and moisture in the processing chamber by exhausting gas in the processing chamber is provided on a wall which is provided inside the hermetically sealed processing chamber and (2) which constitutes the processing chamber. And an inert gas inlet for introducing an inert gas from the outside of the processing chamber into the inside of the processing chamber are installed. (3) The processing chamber applies power to the carbonaceous raw material and a counter electrode. It is characterized in that plasma is generated by an arc generated at the time.

In the present invention, "fullerene" means
It refers to a spherical or substantially spherical closed carbon cluster such as C ₆₀ , C ₇₀ , and C ₇₈ , and usually C ₆₀ and C ₇₀ are the main constituents.

In the present invention, "long product" refers to a product having a length of 1 m or more.

In the present invention, "long time" means a range of time in which the raw material of the long product can be continuously processed to the end.

"Carbonaceous raw material" used in the present invention
A flexible long carbonaceous raw material is used, and specifically, a carbon fiber bundle, a carbon film, a carbon rod, and a mixture of one or more carbonaceous powders are used. It For the carbon fiber bundle, a bundle of dozens or hundreds of carbon fibers may be used. Since the carbon fiber bundle and the carbon film itself have a long and flexible property, they can be used alone.

When two or more kinds of carbonaceous raw materials are used in combination, for example, a carbon rod or carbonaceous powder is combined with a long and flexible carbonaceous raw material to more specifically For example, a long carbon fiber braid is filled with carbonaceous powder or a short carbon rod, or a long carbon film is entangled with carbon fibers. By enclosing a carbonaceous powder or a short carbon rod in a long carbon film, it can be used as a flexible long carbonaceous raw material. These carbonaceous raw materials in the present invention are flexible enough to be compactly wound around a carbonaceous raw material supply device such as a creel or bobbin.

The carbonaceous raw material used in the present invention preferably has a volume resistivity of 10 ⁻³ Ω · cm or less and an effective area of 1 mm ² or more. The volume resistivity is 10 ⁻³ Ω · c
The carbon content of the carbonaceous raw material is 96% if it is larger than m.
The above is not the case, the graphite layer is not sufficiently developed, and the graphitivity is low. When such a carbonaceous raw material having a low carbon content is used for the production of fullerenes, the yield of fullerenes obtained by arc discharge is reduced, which is not preferable. The reason for this is not clear, but carbonaceous raw materials with low graphitization do not decompose carbon to the atomic level during arc discharge, and carbon is scattered in relatively large units, resulting in a low fullerene yield. Presumed. Usually, it is preferable to use a carbonaceous raw material obtained by carbonizing at 2000 ° C. or higher for efficient synthesis of fullerenes.

The reason why the effective cross-sectional area of the carbonaceous raw material used in the present invention is preferably 1 mm ² or more is
This is for ensuring a stable discharge and improving efficiency in terms of production such as fullerene synthesis rate and yield, and a particularly preferable range changes depending on the amount of electric power applied.

The carbonaceous raw material in the present invention preferably has an apparent bulk density of 0.5 g / cm ³ or more. If the bulk density is less than 0.5 g / cm ³ , the stability of discharge during arc discharge becomes poor, and as a result, the synthesis efficiency of fullerene decreases.

Next, the method for producing fullerenes of the present invention will be described.

The above-mentioned carbonaceous raw material is held and arranged in a carbonaceous raw material supply device installed in the processing chamber. Since the carbonaceous raw material used in the present invention is a flexible and long material, it can be held in a compact and large amount around a carbonaceous raw material supply device such as a creel or bobbin.

The carbonaceous raw material is held in the carbonaceous raw material supply device.
The processing chamber in the arranged state is once brought to an ultrahigh vacuum of 10 ^-2 mmHg or less, and then an inert gas is continuously flowed into the processing chamber at a flow rate of 10 to 1000 ml / min, while the inside of the processing chamber is vacuum pumped. While evacuating, the pressure in the processing chamber is adjusted to be in the range of 5 mmHg to 500 mmHg.

Thus, the inside of the processing chamber is once reduced to 10 ^-2 mmHg.
By making the following ultra-high vacuum, the atmospheric gas in the processing chamber is removed to the outside of the reaction system, and the components that inhibit the fullerene synthesis contained in the processing chamber, such as oxygen and water, are moved to the outside of the reaction system. Can be eliminated. At this time, oxygen and water contained in the carbonaceous raw material placed in the processing chamber, for example, oxygen and water contained in the carbon fiber bundle can be simultaneously excluded from the reaction system. After that,
By adjusting the pressure in the processing chamber to a pressure range suitable for arc discharge of 5 mmHg to 500 mmHg, fullerene can be efficiently produced by arc discharge.

As the inert gas supplied into the processing chamber, helium gas, argon gas, krypton gas, nitrogen gas or a mixed gas thereof which does not inhibit the production of fullerene is preferably used.

Next, in the reaction chamber kept in the above-mentioned atmosphere, the carbonaceous raw material is taken out from the carbonaceous raw material supply device by the conveying device and continuously transported so as to approach the counter electrode installed in the processing chamber. Then, electric power is applied to the carbonaceous raw material and the counter electrode to cause arc discharge.

The method of transporting the carbonaceous raw material to the counter electrode is as follows. The carbonaceous raw material taken out from the carbonaceous raw material supply device can guide the carbonaceous raw material such as a double roller to an arbitrary position on the counter electrode. It is then transported to the counter electrode located below the carrier device, and supplied so that the carbonaceous raw material approaches the appropriate position of the counter electrode due to its own weight. Such a method of supplying and transporting the carbonaceous raw material to the opposite electrode in the present invention, even when a supply trouble occurs in the long carbonaceous raw material,
Since it is designed to approach an appropriate position on the counter electrode by its own weight, there is almost no electric leakage accident that the carbonaceous raw material comes into contact with the outer wall of the processing chamber other than the electrode during transportation of the carbonaceous raw material. It is highly likely.

In the method for producing fullerene of the present invention, it is desirable to rotate the counter electrode, and the long carbonaceous raw material is continuously supplied toward an eccentric position different from the center of rotation of the rotating counter electrode. However, by decomposing the carbonaceous raw material by arc discharge, it is possible to deposit the by-product as a dispersion on the counter electrode.
Regarding the method of rotating the counter electrode, arc discharge may be performed while continuously rotating, or arc discharge may be performed while rotating intermittently.

By causing the counter electrode to rotate in such a manner, the deposits deposited on the counter electrode do not concentrate and grow in one place on the counter electrode, and the deposits are uniformly dispersed and formed on the counter electrode. Therefore, it is possible to suppress the fluctuation of the discharge current during operation caused by the growth of the deposit such that the deposit functions as a counter electrode and the distance between the electrodes is shortened. It is possible to prevent deposits caused by the above from touching the wall of the processing chamber and causing insulation failure. And since the present invention can prevent such inconvenience as much as possible, there is an advantage that the discharge time of the fullerene manufacturing apparatus can be taken long, and it is possible to efficiently synthesize fullerenes from a carbonaceous raw material by arc discharge for a long time. It will be possible.

When the counter electrode is rotated intermittently,
When the counter electrode stopped rotating, electric power was applied between both electrodes to continue to generate fullerenes, and when the amount of deposits deposited on the counter electrode reached a certain amount, the electric power between the electrodes was The application is stopped, and then the counter electrode is rotated to a certain position so as to be displaced, the rotation of the counter electrode is stopped, and electric power is again applied between both electrodes to perform arc discharge to generate fullerenes.

Since the long carbonaceous raw material used in the present invention is particularly flexible enough to be wound on a creel, bobbin, etc., the carbonaceous raw material approaches the counter electrode by its own weight. When the arc discharge is continued and the counter electrode is continuously rotated while being discharged, the carbonaceous raw material may be pulled toward the deposit due to the arc discharge, and therefore the carbonaceous raw material may be interlocked with the rotation of the deposit. So
In order to avoid such interlocking of the carbonaceous raw material, it is advantageous to use the above-described method of intermittently performing discharge and rotation alternately.

The material used for the counter electrode for producing the fullerene of the present invention is preferably a processed product of a graphite plate, and its shape and size is preferably a disc shape having a diameter of 5 cm or more.

The method of applying electric power to the carbonaceous raw material and the counter electrode is, for example, to set a specific portion in contact with the carbonaceous raw material supplied or conveyed by the carbonaceous raw material supply device or the conveyance device as a conductive material, Electric power can be applied to the carbonaceous raw material and the counter electrode through this conductive portion. For example, electric power can be applied to the carbonaceous raw material by energizing a roller portion of a carbonaceous raw material supply device or a conveying device such as a double roller.

The electric power applied to the carbonaceous raw material is a voltage of 10 to 100 V in order to efficiently synthesize fullerenes.
Then, it is preferable to flow a current having a current density of 100 to 1000 A / cm ² . The current used for discharging may be alternating current or direct current.

Since the synthesis rate of fullerene varies depending on the material of the raw material, the applied power, and the state of the atmosphere, these conditions must be taken into consideration in the production of fullerene. To efficiently produce fullerenes from a carbonaceous raw material by arc discharge for a long time, for example,
This can be performed by controlling the feeding speed of the carbonaceous raw material so that a preset current during arc discharge can be kept constant.

During operation of the fullerene production apparatus of the present invention, it is necessary to cool the roller section and the counter electrode of the transfer apparatus with water or air. Further, by guiding the inert gas introduced into the processing chamber to the vicinity of the arc discharge and spraying the inert gas at a specific flow rate, the counter electrode and the carbonaceous raw material can be cooled and the yield of fullerene can be increased. it can.

The substance produced from the carbonaceous raw material by the arc discharge in the present invention is a soot-like black powder and a component containing fullerene which is scattered in the processing chamber and a deposit which is vapor-deposited on the counter electrode side and firmly stacked to grow. Divide into components that consist of things. This deposit does not contain fullerenes, but is a component made of a graphite material containing nanotubes and the like. This deposit can be recovered from the counter electrode and reused as a carbonaceous raw material. The soot containing the scattered fullerene is collected in the soot receiver installed around the counter electrode. Fullerene in recovered soot is about 5 to 20% by weight
Exist in proportions.

By immersing this soot in an organic solvent such as toluene, the fullerene is separated into a part soluble in the organic solvent and a part insoluble in the organic solvent. The presence of fullerene is confirmed because the solution turns brown when dissolved in an organic solvent. Fullerene dissolved in an organic solvent mainly contains C ₆₀ , C ₇₀ , C _{78 and the} like. Usually, in the fullerene production method of the present invention, about 80% of C ₆₀ is contained in the fullerene dissolved in the organic solvent, and the remaining components are mixed with a high molecular weight fullerene such as C ₇₀ . .

The fullerene confirmation means and the yield measurement can be performed, for example, as follows. Soot 1
About 100 g of toluene is added to g to dissolve the fullerenes in the soot in toluene. Next, the soot in the solution is filtered so that the resulting filtrate becomes brown, or by subjecting the filtrate to a high performance liquid chromatogram,
Make sure it contains fullerenes. By evaporating toluene from this filtrate, fullerenes are obtained as solids (crystals). This weight is measured to determine the yield.

On the other hand, the fullerene solution obtained by filtering off the soot component that is insoluble in the organic solvent is separated and purified by passing through a column filled with activated carbon and the like to obtain high-purity C ₆₀ as a product. To be Alternatively, the components such as C ₆₀ , C _70, or C ₇₈ can be separately collected by a separation and purification method such as high performance liquid chromatogram.

In the present invention, these long carbonaceous raw materials are tightly and in large quantities wound around a carbonaceous raw material supply device such as a creel or bobbin and installed in the reaction chamber.
It is a batch processing period until the carbonaceous raw material placed in the processing chamber is consumed under the condition that oxygen, water, etc., which have an adverse effect on fullerene production, are excluded as much as possible. It is possible to efficiently supply fullerene by supplying a large amount of raw material on the counter electrode continuously for a long period of time without returning to atmospheric pressure.

The fullerenes synthesized by the method and apparatus for producing fullerenes of the present invention have electric / electronic materials such as electrodes, sensors or electronic elements, magnetic materials such as toners, pharmaceutical raw materials, and light conversion functions. It is effective for optical materials, superconducting materials, energy storage materials, etc.

[0042]

【Example】

[Embodiment 1] FIG. 1 shows an example of a fullerene production apparatus utilizing arc plasma discharge. In FIG. 1, reference numeral 1 denotes a carbonaceous raw material supply device such as a creel or bobbin which holds a long flexible carbonaceous raw material 2 by winding or the like. Reference numeral 3 denotes a transporting device that can transport the carbonaceous raw material 2 supplied from the carbonaceous raw material supply device 1 and guide it to an arbitrary position on the counter electrode 4. For example, as shown in FIG. used. The counter electrode 4 has a disk shape and is rotatable, and the tip of the counter electrode 4 that hangs due to its own weight of the carbonaceous raw material 2 conveyed from the conveying device 3 faces the disk-shaped horizontal surface of the counter electrode 4. . Around the counter electrode 4, a soot receiver 5 for collecting scattered fullerenes is surrounded.

The carbonaceous raw material supply device 1, the transfer device 3,
The counter electrode 4 and the soot receiver 5 are installed in a processing chamber 6 capable of maintaining a high vacuum state. On the wall of the processing chamber 6,
An exhaust port 10 communicating with a vacuum pump 11 for exhausting the gas in the processing chamber 6 to create a high vacuum state is installed, and the atmosphere in the processing chamber 6 is inert at a desired gas pressure suitable for arc discharge. An inert gas inlet 8 communicating with an inert gas cylinder 9 for creating a gas atmosphere is installed. The tip of the inert gas introduction port 8 introduced into the processing chamber 6 should be close to the vicinity where these arc discharges are performed so that the tip portions of the counter electrode 4 and the carbonaceous raw material 2 can be cooled. Is desirable to stabilize and increase the yield of fullerene. Power is supplied to the transfer device 3 and the counter electrode 4 from a power source 7 provided outside the processing chamber 6.

In the fullerene manufacturing apparatus of FIG. 1, an AC power source was used as the power source 7, and the current was set to 90A and the voltage was set to 20V. The carbonaceous raw material 2 is made of Toho Rayon Co., Ltd.'s Besfite (registered trademark) HM35-12K carbon fiber (volume resistivity: 1.0 × 10 ⁻³ Ω · cm), and 24 fibers are bundled and the diameter is 5 mm. A carbon fiber bundle having a length of 10 m was used. The apparent bulk density of this carbon fiber bundle was about 1.0 g / cm ³ . The carbon fiber bundle is wound around a creel as the carbonaceous material supply device 1 in the processing chamber 6, and is separated by 10 mm between the tip of the carbon fiber bundle and the counter electrode 4 through a double roller as the transport device 3. I placed it.

After arranging the carbonaceous raw material 2 in this way, the processing chamber 6 is closed and the gas therein is vacuum pump 11
The pressure in the processing chamber 6 is reduced to 1
After setting to 10 ⁻² mmHg, helium gas was introduced into the processing chamber 6 through the inert gas inlet 8. The helium gas flow rate was set to 300 ml / min, and the pressure in the processing chamber 6 was set to 30 mmHg by balancing the inflow amount of helium gas and the exhaust of the vacuum pump 11.

Next, the power source 7 is turned on and the feeding double roller is rotated to direct the carbonaceous raw material 2 toward the counter electrode 4 by about 10 mm /
Moved at a feed speed of minutes. Discharge started after about 60 seconds, and the carbonaceous raw material 2 was continuously supplied at a feeding speed of 5 to 20 mm / min while observing the change in the current value. The current value during arc discharge was about 90 A, and the apparent current density was about 460 A / cm ² .

Further, the operation of once stopping the arc discharge at intervals of 30 minutes, then rotating the counter electrode 4 by about 25 ° and restarting the discharge was repeated, and the deposit accumulated on the side of the counter electrode 4 was dispersed. . After operating for about 10 hours to carry out the discharge treatment, the power supply 7 was turned off, and it was left for 10 minutes to cool. The inside of the processing chamber 6 was returned to atmospheric pressure, and the soot accumulated in the soot receiver 5 was recovered, and the amount thereof was 62 g. The remaining carbon fiber bundle was about 3.7 m, and the total weight of the carbonaceous raw material 2 decomposed by discharge was 125 g.

The soot thus obtained was immersed in toluene to dissolve the fullerenes contained in the soot in toluene.
The weight of the extracted fullerenes was 3.0 g, and the yield from the raw materials was 2.4%.

[Comparative Example 1] Carbon materials were produced under the same conditions as in Example 1 except that the same fullerene production apparatus and the same carbonaceous raw material as in Example 1 were used, and only the helium gas pressure in the production conditions was changed to 1 mmHg. The raw material was continuously supplied for 10 hours to the counter electrode side and subjected to arc discharge treatment.

After the end of the arc discharge, the power source was turned off and the soot was collected. The amount of soot collected was 68 g. The remaining carbon fiber bundle was about 3.5 m, and the total weight of the carbonaceous raw material decomposed by arc discharge was 130 g.

The soot thus obtained was immersed in toluene to dissolve the fullerenes contained in the soot in toluene.
The weight of the extracted fullerenes was 0.83 g, and the yield from the raw materials was 0.64%. From this result, it is understood that when the pressure of helium gas is too low, the yield of fullerene is reduced.

[Comparative Example 2] Carbon materials were produced under the same conditions as in Example 1 except that the same fullerene production apparatus and the same carbonaceous raw material as in Example 1 were used and only the helium gas pressure in the production conditions was changed to 750 mmHg. The raw material was continuously supplied for 10 hours to the counter electrode side and subjected to arc discharge treatment.

After the arc discharge was completed, the power was turned off and the soot was collected. The amount of soot collected was 37 g. The remaining carbon fiber bundle was about 3.8 m, and the total weight of the carbonaceous raw material decomposed by arc discharge was 123 g.

The soot was immersed in toluene to dissolve the fullerenes contained in the soot in toluene. The weight of the extracted fullerenes was 0.67 g, and the yield from the carbonaceous raw material was 0.54%. From this result, it is understood that the yield of fullerene tends to decrease in the region where the pressure of helium gas is high.

Comparative Example 3 As the carbonaceous raw material, Vesfite (registered trademark) HTA-12K carbon fiber manufactured by Toho Rayon Co., Ltd. (volume resistivity: 1.5 × 10 ⁻³ Ω · cm) was used. The bundle was bundled into a carbon fiber bundle having a diameter of 5 mm and a length of 10 m. The apparent bulk density of this carbon fiber bundle is about 1.1 g.
/ Cm ³ .

The above carbon fiber bundle was continuously supplied to the counter electrode side for 10 hours under the same apparatus and the same manufacturing conditions as in Example 1,
Arc discharge treatment was performed.

After the arc discharge was completed, the power was turned off and the soot was collected. The amount of soot collected was 41 g. The remaining carbon fiber bundle was about 3.6 m, and the total weight of the carbonaceous raw material decomposed by arc discharge was 138 g.

The soot thus obtained was immersed in toluene to dissolve the fullerenes contained in the soot in toluene.
The weight of the extracted fullerenes was 0.41 g, and the yield from the raw materials was 0.30%. From this result, it is understood that the yield of fullerene tends to be influenced by the volume resistivity of the carbonaceous raw material.

Example 2 The same fullerene manufacturing apparatus as in Example 1 was used, a DC power source was used as a power source, and the fullerene current was set to 100 A and the voltage to 30 V.
As the carbonaceous raw material, a carbon composite of a carbon fiber braid and a graphite rod is used, and specifically, the carbon fiber braid is Vesfite (registered trademark) HTA-3 manufactured by Toho Rayon Co., Ltd.
2g of braid of 5g / m knitted with K carbon fiber in high temperature furnace
Heat treated at 800 ° C for 5 minutes (volume resistivity: 9.0
× 10 ⁻⁴ Ω · cm) and carbon for vacuum deposition (Hitachi Chemical Co., Ltd., volume resistivity: 3.5 × 10 ⁻⁴ Ω · cm) was used as the graphite rod.

Short carbon rods having a diameter of 5 mm and a length of 30 mm were packed in a line in the carbon fiber braid heat-treated as described above to prepare a composite fiber bundle having a length of 10 m. The apparent bulk density of this composite fiber bundle is about 1.2 / cm.
^{Was 3} . This composite fiber bundle was wound around the creel in the processing chamber, and was placed so that the distance between the tip of the composite fiber bundle and the counter electrode was 10 mm through the two continuous rollers.

After installing the raw materials, the processing chamber is closed, the gas inside is exhausted by a vacuum pump, and the pressure inside the processing chamber is set to 1 ×.
After the pressure was set to 10 ⁻² mmHg or less, helium gas was then introduced into the processing chamber. By balancing the flow rate of helium gas and the exhaust by the vacuum pump, the flow rate of helium gas is 200 ml / min and the pressure in the processing chamber is 100 mmHg.
Set to.

The power was turned on, the two rollers were rotated to start arc discharge, and the carbonaceous raw material was continuously supplied at a feed speed of 5 to 10 mm / min. The current value during arc discharge is almost 100 A, and the apparent current density is about 510 A.
Was / cm ² .

Further, the operation of once stopping the arc discharge at intervals of 30 minutes, then rotating the counter electrode by about 25 °, and starting the arc discharge again was repeated, so that the deposit accumulated on the counter electrode side was dispersed. After operating for about 10 hours to perform arc discharge treatment, the power supply was turned off and the mixture was left for 10 minutes to cool. The reaction chamber was returned to atmospheric pressure, and the soot accumulated in the soot receiver was recovered. The amount of soot collected was 57 g. The remaining composite fiber bundle was about 4.2 m, and the total weight of the carbonaceous raw material decomposed by arc discharge was 137 g.

The soot thus obtained was dipped in toluene to dissolve the fullerenes contained in the soot in toluene.
The weight of the extracted fullerenes was 4.8 g, and the yield from the carbonaceous raw material was 3.5%.

[Example 3] The same fullerene production apparatus as in Example 1 was used. A direct current power source was used as a power source, and the current was set to 100 A and the voltage was set to 20 V.
The carbonaceous raw material was carbon fiber (volume resistivity: Vesfite (registered trademark) UM46-12K manufactured by Toho Rayon Co., Ltd.).
1.0 × 10 ⁻³ Ω · cm) and 10 Besfite (registered trademark) UM63-12K carbon fibers (volume resistivity: 7.
Fifty (0 × 10 ⁻⁴ Ω · cm) were mixed and bundled into a composite fiber bundle having a diameter of about 5.5 mm and a length of 10 m. The apparent bulk density of this composite fiber bundle is about 1.0 g / c.
It was m ³ . The composite fiber bundle was wound around a creel in the processing chamber, and the composite fiber bundle was placed between the two rollers so that the distance between the tip of the composite fiber bundle and the counter electrode was 10 mm.

After installing the carbonaceous raw material in this way, the reaction chamber was closed, the gas inside was exhausted from the exhaust port by the vacuum pump, and the pressure in the processing chamber was adjusted to 1 × 10 ^-2 mmHg or less. Helium gas was introduced into the reaction chamber. The flow rate of helium gas at that time was set to 300 ml / min, and the pressure in the processing chamber was set to 20 mmHg.

The power supply was turned on, the feed roller was rotated to start arc discharge, and the carbonaceous raw material was continuously supplied at a feed speed of 5 to 10 mm / min. The current value at the time of arc discharge is about 98 A, and the apparent current density is about 500 A /
cm ² .

Further, the operation of once stopping the arc discharge at intervals of 30 minutes, then rotating the counter electrode by about 25 ° and restarting the arc discharge was repeated, so that the deposit accumulated on the counter electrode side was dispersed. After operating for about 10 hours to perform arc discharge treatment, the power supply was turned off and the mixture was left for 10 minutes to cool. The processing chamber was returned to atmospheric pressure, and the soot accumulated in the soot receiver was collected. The amount of soot collected was 70 g. The remaining composite fiber bundle was about 4.0 m, and the total weight of the carbonaceous raw material decomposed by discharge was 145 g.

The soot thus obtained was dipped in toluene to dissolve the fullerenes contained in the soot in toluene.
The weight of the extracted fullerenes was 6.6 g, and the yield from the raw materials was 4.6%.

[Comparative Example 4] The same fullerene producing apparatus as in Example 1 and the same raw material as in Example 3 were used, except that the current during arc discharge was set to 15 A and the voltage was set to 20 V. Under the same conditions as above, the carbonaceous raw material was continuously supplied for 10 hours to the counter electrode side, and the arc discharge treatment was performed.
The actual current value during arc discharge was about 14 A, and the apparent current density was about 71 A / cm ² .

After the arc discharge was completed, the power was turned off and the soot was collected. The amount of soot collected was 12 g. The remaining composite fiber bundle was about 8.0 m, and the total weight of the carbonaceous raw material decomposed by arc discharge was 40 g.

The soot thus obtained was immersed in toluene to dissolve the fullerenes contained in the soot in toluene, but the fullerenes were hardly extracted and the yield from the carbonaceous raw material was 0%. Met.

[Comparative Example 5] A carbonaceous raw material was supplied to the counter electrode side under the same fullerene production apparatus as in Example 1 and the same production conditions as in Example 3 to perform arc discharge treatment. However,
The operation of rotating the counter electrode intermittently during arc discharge was not performed, and the counter electrode was fixed and the carbonaceous raw material was decomposed by arc discharge.

50 minutes after the start of the arc discharge, the arc discharge current became 110 A or more and the current value became unstable, so the arc discharge was stopped.

When the inside of the processing chamber was checked by turning off the power supply, it was estimated that deposits were grown on the counter electrode with a length of about 5 cm, and the current value fluctuated due to this influence.

The amount of soot collected was 5.7 g. The remaining composite fiber bundle is about 9.5 m, and the total weight of the carbonaceous raw material decomposed by arc discharge in 50 minutes is 12
g. The obtained soot was immersed in toluene to dissolve the fullerenes contained in the soot in toluene.
The weight of the extracted fullerenes was 0.46 g, and the yield from the carbonaceous raw material was 3.8%.

[0077]

In the fullerene production method and apparatus according to the present invention, the treatment chamber in which the carbonaceous raw material is placed is once evacuated to a high vacuum, and then the pressure condition suitable for arc discharge is established. The high-vacuum treatment removes substances, such as oxygen and water, which are contained in the raw materials and have a bad influence on the production of fullerenes to the outside of the processing chamber, so that the fullerenes can be produced efficiently.

In the fullerene production method and the production apparatus thereof according to the present invention, since the long and flexible carbonaceous raw material is held by the carbonaceous raw material supply device installed in the treatment chamber, the carbonaceous material which can be placed in the treatment chamber Despite the large amount of raw materials,
The overall size of the device is also compact, and the device can be manufactured relatively inexpensively, which is advantageous in terms of cost.

The fullerene production method and the production apparatus therefor according to the present invention allow a large amount of carbonaceous raw material to be placed in the processing chamber, and further, arc discharge treatment can be performed for a long period of time without returning to atmospheric pressure. Fullerenes can be produced.

The method for producing fullerene and the apparatus for producing the same according to the present invention, when the carbonaceous raw material is used as an electrode and arc-discharged with the counter electrode, the carbonaceous raw material is supplied from above by its own weight and is located below. Since discharge is performed between the counter electrodes and the counter electrode side is rotated intermittently or continuously in the fullerene manufacturing process, concentrated deposits are not deposited on the counter electrodes. Therefore, since it is possible to disperse and deposit the deposits evenly on the counter electrode,
The discharge abnormality caused by the grown deposit can be suppressed, and the fullerene can be manufactured efficiently and stably for a long time.

[Brief description of drawings]

FIG. 1 is a schematic view of a fullerene production apparatus of the present invention.

[Explanation of symbols]

 1 carbonaceous raw material supply device 2 carbonaceous raw material 3 carrier device 4 counter electrode 5 soot receiver 6 processing chamber 7 power supply 8 inert gas inlet 9 inert gas cylinder 10 exhaust port 11 vacuum pump

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyozo Miyata 3-18-26 Shimohoya, Hoya-shi, Tokyo

Claims (12)

[Claims] 1. A long, flexible carbonaceous raw material is placed in a processing chamber, (2) The processing chamber is once brought to an ultrahigh vacuum of 10 ^-2 mmHg or less, and (3) the processing chamber is provided. The pressure in the processing chamber is adjusted to 5 mmHg to 500 mmHg by introducing an inert gas, and (4) the carbonaceous raw material is continuously supplied so as to approach the counter electrode installed in the processing chamber. A method for producing fullerene capable of continuous production for a long time, which comprises producing a fullerene from a carbonaceous raw material by applying electric power between both electrodes using a carbonaceous raw material as an electrode to cause arc discharge. 2. The method for applying electric power between both electrodes is performed by applying electric power to a device for transporting and supplying a carbonaceous raw material to the counter electrode and to the counter electrode. A method for producing fullerene which can be continuously produced for a long time as described. 3. The method for applying an electric power between the both electrodes is performed by applying a current of 100 to 1,000 A / cm ^{2 to} the carbonaceous raw material, which enables continuous production for a long time. Fullerene manufacturing method. 4. The method for applying electric power between the two electrodes is such that the electric power is applied while supplying the carbonaceous raw material toward an eccentric position different from the center of rotation of the counter electrode that is continuously or intermittently rotating. 4. The method for producing fullerene which can be continuously produced for a long time according to claim 1, 2 or 3, wherein the deposition is performed while depositing a deposit to be deposited on the counter electrode so as to be dispersed on the counter electrode. 5. The method for producing fullerene according to claim 4, wherein when the counter electrode is rotated intermittently, electric power is applied between both electrodes to generate fullerene when the counter electrode stops rotating. However, the deposit is deposited on the counter electrode, and then the application of electric power between the electrodes is stopped, and then the counter electrode is rotated so as to shift the position of the counter electrode. A method for producing fullerene capable of continuous production for a long time, characterized by applying electric power. 6. The method for supplying the carbonaceous raw material so that the carbonaceous raw material is brought closer to the counter electrode, the carbonaceous raw material is transported by being sandwiched by a conveying device, and the carbonaceous raw material is directed toward a counter electrode located below the conveying device. The method for producing fullerene capable of continuous production for a long time according to claim 1, 2, 3, 4, or 5, wherein the fullerene is brought closer to itself by its own weight. 7. The carbonaceous raw material has a volume resistivity of 10 ⁻³ Ω.
A carbon fiber bundle having an effective area of 1 mm ² or more, a carbon film, a carbon rod, a carbonaceous powder, or a combination of two or more kinds.
A method for producing a fullerene according to 2, 3, 4, 5 or 6, which can be produced continuously for a long time. 8. The method for producing fullerene capable of continuous production for a long time according to claim 7, wherein the carbon fiber bundle is in the form of a braid, a twisted yarn, or a composite yarn. 9. The arc discharge is performed by controlling the feed speed of the carbonaceous raw material so as to keep the current during the arc discharge constant. The method for producing fullerene according to 6, 6, 7 or 8 which can be continuously produced for a long time. 10. (1) A carbonaceous raw material supply device capable of arranging and supplying a long flexible carbonaceous raw material, a conveying device capable of guiding the carbonaceous raw material to an arbitrary position on a counter electrode, The rotatable counter electrode facing the tip of the carbonaceous raw material, and the soot receiver installed around the counter electrode are provided inside a process chamber that can be sealed. (2) The process chamber An exhaust port connected to a vacuum device that can exhaust the gas in the processing chamber to remove oxygen and moisture in the processing chamber, and an inert gas from the outside of the processing chamber to the inside of the processing chamber. An inert gas inlet that can be used is installed, and (3) the processing chamber is configured so that plasma is generated by an arc generated when electric power is applied to the counter electrode and the carbonaceous raw material. Fullerene manufacturing equipment characterized by. 11. The fullerene production apparatus according to claim 10, wherein the carbonaceous raw material supply device has a function of holding and delivering the carbonaceous raw material. 12. The apparatus for producing fullerenes according to claim 10, wherein the conveying device is a double roller in which a portion in contact with the carbonaceous raw material is made of a conductive material.