JPH05294606A - Selective conversion of high-molecular weight fullerene to c60 - Google Patents

Abstract

PURPOSE:To provide a process for converting a less important high-molecular weight fullerene having carbon atoms of >=70 (C70+) into more useful fullerene C60 in high selectivity and efficiency. CONSTITUTION:High molecular weight fullerene having carbon atoms of >=70 and a closed shell structure is hydrogenated under a hydrogen pressure of 30-180 kg/cm<2>G at 80-240 deg.C in the presence of a hydrogenation catalyst and the obtained hydrogenation product is dehydrogenated to effect selective conversion of the high-molecular weight fullerene into C60 fullerene.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for selectively converting high molecular weight fullerenes to C ₆₀ , and more specifically, it selects high molecular weight fullerenes having 70 or more carbon atoms into more useful fullerene C ₆₀ . Well on how to convert.

Fullerene C ₆₀ is expected to be used for various purposes including derivatives thereof. For example, fullerene C ₆₀ is used as a new material and a new material in various fields such as electrically conductive materials and electric / electronic materials such as superconductor materials. Alternatively, they are useful as raw materials for their synthesis.

[0003]

2. Description of the Related Art Recently, a new type of molecular carbon material called a closed shell type carbon cluster (spherical macromolecule) having 60, 70, 84 carbon atoms has been synthesized and attracted attention. Carbon clusters with this special structure
It is also called a fullerene, and depending on the number of carbon atoms constituting the molecular skeleton, it is called fullerene C ₆₀ , C ₇₀ , C ₈₄ or the like, or simply C ₆₀ , C ₇₀ , C ₈₄ or the like.
Since these fullerenes are new carbon materials and are expected to show unique physical properties because they have a special molecular structure, studies on their properties and application development are being actively pursued.

Among these fullerenes of various carbon numbers, C ₆₀ is a soccer ball type spherical non-saturated molecule composed of a 6-membered ring and a 5-membered ring and is the most basic fullerene with good symmetry. Since it is relatively stable and easy to manufacture, it has attracted particular attention in various research fields and applied fields, and is expected to be the most useful in terms of various new materials including its derivatives.

As described above, fullerene C ₆₀ is forming a major field of application, including its derivatives, and its usefulness has become clear, especially as a material for superconductors, etc. -Expectations as new materials and new materials are becoming reality in various fields of use including the electronic field.

However, although high molecular weight fullerenes having 70 or more carbon atoms such as C ₇₀ have been isolated and studied, they do not exhibit properties such as superconductivity as seen in fullerene C _60. Is becoming clear.

That is, regarding the industrial importance of these fullerenes, C ₆₀ is much larger than other fullerenes such as C ₇₀ , and establishment of a technique for obtaining fullerenes C ₆₀ with higher selectivity is required. Strongly desired.

By the way, these fullerenes are generally synthesized by evaporating graphite by arc discharge (resistance heating method) or by laser light, and in each case, various carbons are produced. Obtained as a soot containing a mixture of several fullerenes.
The fullerenes contained in this soot are at most 1
It is as small as 0% by weight. Of the fullerenes, usually about 80 to 90% is fullerene C ₆₀ ,
About 15% is C ₇₀ , and other high molecular weight fullerenes are also contained at a ratio of several%. As described above, fullerene C ₆₀ is the largest of the fullerenes obtained, but high-molecular-weight fullerenes (C ₇₀₊ ) having C ₇₀ or higher are also by-produced in a considerable proportion. The fullerenes obtained as a mixture in soot are separated and recovered as composition fullerenes, purified fullerenes, and isolated fullerenes by solvent extraction, chromatographic separation, or the like.

Here, as described above, the fullerene C ₆₀ exhibiting superconductivity and the like, which is regarded as the most important in industry and research and is in great demand, is required to further improve its production efficiency. There is. On the other hand, higher molecular weight fullerenes (C ₇₀₊ ) such as C ₇₀ do not occupy an industrially important position, so demand is low at present and particularly in the future as well. The increase is unlikely to be expected so far. Therefore, unless the technology for producing the fullerene C ₆₀ extremely selectively is developed, the fullerene C will increase as the production amount of fullerenes increases.
It is expected that the production of fullerenes other than ₆₀ will become increasingly excessive.

As described above, in the conventional production technology of fullerenes, there is a balance between the production amount (ratio) of shortage of fullerene C ₆₀ and excess of high molecular weight fullerene (C ₇₀₊ ) due to marked differences in demand and usefulness. Badness was a big problem.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances. An object of the present invention is to provide high molecular weight fullerenes (C) having a carbon number of 70 or more (C
It is to provide a method of efficiently converting ₇₀₊ ) into a more useful fullerene C ₆₀ with high selectivity.

[0012]

The present inventors have found that if a high molecular weight fullerene having a carbon number of more than 60, such as fullerene C ₇₀ , can be converted into fullerene C ₆₀ with good selectivity, the method described above can be used. We thought that it was extremely effective as a means to solve the problem, and conducted intensive studies on the method.

As a result, the fullerene C ₇₀ or the like has 70 carbon atoms.
When the above high molecular weight fullerenes (C ₇₀₊ ) are hydrogenated under various reaction conditions (temperature and hydrogen pressure) using various hydrogenation catalysts, these C ₇₀₊ are simply hydrogenated. In other words, a very specific reaction, which is a combination of selective reduction of carbon number to 60 and hydrogenation, easily occurs, and it is converted to fullerene C ₆₀ hydride (hydrogenate) with good selectivity and high yield. I found a very important fact. Further, the C ₇₀₊ hydrogenation product thus obtained (that is, the hydrogenated fullerene containing the hydrogenated fullerene C ₆₀ derived from the raw material fullerene C ₇₀₊ ) may be used as a mixture or after appropriate separation. It was found that dehydrogenation can be easily carried out under various conditions, and hydrogenation fullerene C ₆₀ can be easily converted to fullerene C ₆₀ by this dehydrogenation. That is, by combining these unique hydrogenation reactions and ordinary dehydrogenation reactions, high-molecular-weight fullerenes having a carbon number of 70 or more, such as C ₇₀ , which is less important, are more efficiently and more efficiently selected as more important fullerene C _60. We were able to develop a new technology that could be well converted. In addition, in this new technology, hydrogenated fullerenes other than hydrogenated fullerene C ₆₀ produced by hydrogenation of the raw material fullerene C ₇₀₊ can be converted to the corresponding fullerene by dehydrogenation, and again, Raw material fullerene C
Since it can be effectively used as _70+, etc., it was confirmed that this is also an efficient process.

The present inventors have completed the present invention based on these findings.

That is, according to the present invention, a high molecular weight fullerene having a closed shell structure having a carbon number of 70 or more is added in the presence of a hydrogenation catalyst at a hydrogen pressure of 30 to 180 kg / cm ² G and a temperature of 80.
It provides a process for the selective conversion of high molecular weight fullerenes to C ₆₀ which is characterized by hydrogenating under the conditions of ˜240 ° C. and then dehydrogenating the resulting hydride.

In the method of the present invention, as a raw material or raw material component of the hydrogenation step, at least a high molecular weight fullerene having a closed shell structure and having 70 or more carbon atoms (hereinafter referred to as raw material fullerene C _70+). There is). As the raw material fullerene C ₇₀₊ , any kind and manufacturing method can be used as long as it has a closed shell structure composed of carbon atoms peculiar to fullerenes and has a carbon number of 70 or more. The raw material fullerenes C ₇₀₊ include fullerenes C _n (provided that n is
Represents an integer of 70 or more. ) Various fullerenes, specifically, for example, fullerenes,
Examples thereof include those represented by C ₇₀ , C ₇₆ , C ₇₈ , C ₈₀ , C ₈₂ , C _{84 and the} like. In addition, these may be used individually by 1 type, and 2 or more types may also be used as a mixture etc. Further, these fullerenes having 70 or more carbon atoms can be used as a variety of purities or purities containing other components, as long as the object of the present invention is not impaired. For example, other fullerenes (For example, fullerene C ₆₀ etc.) and a mixed fullerene of a mixture and other fullerenes such as fullerene C _{60 and the} like, and further used as a low-purity state containing soot together You can also Furthermore, if it is converted into a hydride of fullerene C _{60 under} the hydrogenation conditions in the method of the present invention, derivatives of various fullerenes having 70 or more carbon atoms (for example, metal-encapsulated fullerenes C
₇₀₊ , already hydrogenated fullerenes C ₇₀₊ , alkylated fullerenes C _70+, etc.) can also be used as raw material fullerenes C ₇₀₊ or components thereof.

In the method of the present invention, the above-mentioned raw material fullerene C ₇₀₊ is used as a raw material or raw material component and hydrogenated using hydrogen gas in the presence of a suitable hydrogenation catalyst. , Hydrogen pressure is 30 ~ 180kg / c
It is important to work under specific conditions in the m ² G range and in the temperature range 80-240 ° C. By carrying out the hydrogenation under these conditions, at least the raw material fullerene C ₇₀₊ can be converted into a hydride of fullerene C ₆₀ with high selectivity and high efficiency. Depending on the conditions, it is possible to convert all of the raw material fullerenes C ₇₀₊ into hydrogenated fullerenes C ₆₀ , but usually it is a hydrogenated product of the raw material fullerenes C _{70 +} together with the hydrogenated fullerenes C _60. Hydrogenated fullerenes C ₇₀₊ are also produced. When a raw material containing fullerene C ₆₀ is used, the fullerene C _{60 in} this raw material is hydrogenated as it is and hydrogenated fullerene C ₆₀
It will be ₆₀ .

[0018] Here, if the the hydrogen pressure in the hydrogenation reaction is less than 30kg / cm ² G, even if the hydrogen feedstock fullerenes C ₇₀₊ as a raw material fullerenes C ₇₀₊ like hydrogenation reaction proceeded The conversion and selectivity to the fullerene C ₆₀ are insufficient, while the hydrogen pressure is 180 kg /
Even if the pressure exceeds cm ² G, the conversion rate to hydrogenated fullerene C ₆₀ and the selectivity are not further improved, which is rather disadvantageous in terms of equipment cost and energy cost.

When the reaction temperature in the hydrogenation reaction is lower than 80 ° C., the reaction of the raw material fullerenes C _{70+ to} the hydrogenated fullerene C ₆₀ does not proceed at a sufficient rate, and the hydrogenation reaction itself is slow. On the other hand, if the reaction temperature is higher than 240 ° C., decomposition of fullerenes such as raw material fullerenes C ₇₀₊ and produced hydrogenated fullerenes C ₆₀ and hydrogenated fullerenes is likely to occur, and in any case, the object of the present invention Can not be fully achieved.

The reaction time for suitably carrying out this hydrogenation reaction varies depending on various conditions such as the type and proportion of the hydrogenation catalyst used, the composition of the starting materials, the reaction temperature and the hydrogen pressure, so it should be set uniformly. However, usually 0.1 to 10
About 0 hours is sufficient.

The hydrogenation catalyst used in the hydrogenation reaction is not particularly limited, and is a known homogeneous catalyst or heterogeneous catalyst used or proposed as a hydrogenation catalyst for hydrocarbons, or a mixture thereof. Various hydrogenation catalysts such as those based on the above can be used. Examples of such hydrogenation catalysts include Cr, Fe, Co, Ni, Mo, Ru,
There are various forms of catalysts made of various metals including transition metals such as Rh, Pd, W, Re, Os, Ir, and Pt. Typical examples of them are, for example, Pt colloid. , Metal catalysts such as metal colloids represented by Raney nickel, Ranel ruthenium, Raney cobalt, etc., metal oxides represented by platinum black, palladium black, ruthenium black, rhodium black, rhenium black, chromium oxide, molybdenum oxide, etc. Catalysts, metal sulfide-based catalysts represented by molybdenum sulfide, rhenium sulfide, and the like, metal compound-based catalysts such as various metal complex-based catalysts, and various types of these metals or metal compounds supported on various carriers. Supported catalyst (for example, Pd /
Carbon, Ru / carbon, Ni / diatomaceous earth, Pd / silica, Pd / alumina, Pd / silica alumina, Ru / silica, Pt / silica, Pt / alumina, Ni / silica,
Various materials such as Co / alumina, molybdena / alumina, chromia / alumina, Rh / silica, Re / silica and the like can be mentioned. Among these, Pd / carbon, Ru / carbon, nickel / diatomaceous earth, and the like can be particularly preferably used. In addition, these hydrogenation catalysts may be used alone, or may be used in combination by mixing two or more kinds or forming a composite.

As the hydrogen gas used in the hydrogenation reaction, not only pure ones but also various ones of various purities or grades such as those for various industrial uses can be used, and also to be used as the hydrogen gas-containing gas. You can

Although the hydrogenation reaction can be carried out without a solvent, it is usually preferable to carry out the reaction in a suitable solvent (or dispersion solvent) from the viewpoint of improving the reactivity. As this solvent, various ones can be used, for example,
Examples thereof include aromatic compounds such as benzene, toluene, xylene and mesitylene, alicyclic hydrocarbon compounds such as cyclohexane, methylcyclohexane and dimethylcyclohexane, and alkanes such as hexane, heptane, octane and decane. These may be used as a single solvent alone, or two or more may be used as a mixed solvent.

Among these, aromatic hydrocarbon solvents such as benzene, toluene, xylene, and mesitylene have high solubility in various hydrogenated fullerenes and, at the same time, in various fullerenes. Since it has sufficiently high solubility, it is particularly preferable from the viewpoint of improving reactivity. However, when these aromatic compounds are used as a solvent or a component thereof, usually, these aromatic compounds are also hydrogenated and converted to the corresponding cycloalkanes accompanying the hydrogenation reaction. The hydrogen will be consumed accordingly. Therefore, cycloalkanes and alkanes are more advantageous in terms of a solvent that does not consume hydrogen excessively.

On the other hand, cycloalkanes and alkanes are
It shows a sufficiently high solubility for various hydrogenated fullerenes such as hydrogenated fullerene C ₆₀ , which is the main object compound of this hydrogenation reaction, but it is a fullerene such as raw material fullerenes C ₇₀₊ and graphite. It does not show sufficient solubility in other carbons. Therefore, by utilizing this fact, it is possible to further facilitate the separation of the produced hydrogenated fullerenes after the hydrogenation reaction.

By carrying out the hydrogenation reaction as described above, the raw material fullerene C ₇₀₊ can be converted into the hydrogenated fullerene C ₆₀ with a sufficiently high selectivity and conversion rate. Further, as described above, although depending on the condition all the raw material fullerenes C ₇₀₊ can be converted into the hydrogenation fullerene C _60, typically, water ingredients fullerenes C ₇₀₊ with hydrogenated fullerene C ₆₀ Hydrogenated fullerenes C _{70+, which} is an _additive, are also produced.

The hydrogenated fullerene C ₆₀ produced from the raw material fullerene C ₇₀₊ by the hydrogenation is usually a mixture of various hydrogenated fullerenes C ₆₀ having 60 carbon atoms but different H / C ratios. Obtained as. Specifically, for example, the general formula C ₆₀ H _m (m is usually 30 to 44
Indicates an integer of degree. ) Are obtained as a mixture of compounds having various H / C ratios. Specific examples of the resulting hydrogenated fullerene C ₆₀ compounds include, for example, C ₆₀ H ₃₀ , C ₆₀ H ₃₂ , C ₆₀ H ₃₄ , C ₆₀ H ₃₆ , and C ₆₀ H.
_{38, C 60 H 40, C} 60 H 42, C , etc. ₆₀ H ₄₄ can be exemplified. The proportions (composition ratios) of these compounds vary depending on the hydrogenation conditions and the like. Therefore, these ratios can be used to control the proportions thereof or selectively select hydrogenated fullerene C ₆₀ having a specific H / C ratio. It is also possible to generate it. Therefore, the method of the present invention is applicable to various raw material fullerenes C
It can also be used as a method for producing hydrogenated fullerene C ₆₀ from _{70+ with} various H / C ratios as described above. However, for the main object of the present invention, since the fullerenes C ₆₀ hydrogenated fullerene C ₆₀ was dehydrogenated mixture of hydrogenated fullerene C ₆₀ with a distribution of H / C ratio by the hydrogenation reaction It suffices to obtain, and not necessarily a specific H
The hydrogenated fullerene C ₆₀ having a / C ratio may not be selectively produced. In that case, the hydrogenation reaction can be selected much more freely, and it is possible to easily select the conditions such that the selectivity to the entire hydrogenated fullerene C ₆₀ and the conversion rate are increased.

On the other hand, the hydrogenation reaction usually produces a hydrogenated product of the raw material fullerene C ₇₀₊ , but this hydrogenated product is also generally produced as a mixture of various H / C ratios. For example, the hydrogenated fullerene C ₇₀ produced is usually
Examples thereof include compounds having various H / C ratios represented by the general formula C ₇₀ H _k (k usually represents an integer of about 30 to 46), and specific examples include C ₇₀ H _30. , C ₇₀ H ₃₂ , C
₇₀ H ₃₄ , C ₇₀ H ₃₆ , C ₇₀ H ₃₈ , C ₇₀ H ₄₀ , C ₇₀ H ₄₂ , C
And the like can be exemplified _{70 H 44, C 70 H 46} . These proportions can also be controlled by adjusting the hydrogenation conditions and the like, but for the main purpose of the present invention, the composition thereof may not be controlled. The hydrogenated fullerenes other than the hydrogenated fullerenes C ₆₀ thus obtained can be appropriately separated and recovered before dehydrogenation and can be used for various purposes. _It is also possible to return the fullerene such as _{70+ to} the fullerene and use it again as a raw material for the hydrogenation reaction or a component thereof in the method of the present invention.

As described above, by the hydrogenation reaction, the raw material fullerene C ₇₀₊ can be converted to the desired hydrogenated fullerene C ₆₀ with high selectivity and high selectivity. A hydrogenation product containing a large amount of hydrogenated fullerene C ₆₀ can be efficiently obtained.

In the method of the present invention, at least the obtained hydrogenated fullerene C ₆₀ is converted into fullerene C ₆₀ by dehydrogenating the hydride which is the product obtained by the hydrogenation. By this dehydrogenation, hydrogenated fullerene C ₆₀ is converted into fullerene C ₆₀ having the same carbon number. Therefore, the hydrogenated fullerene C ₆₀ obtained by the hydrogenation reaction should be quantitatively converted into the desired fullerene C _60. You can also As a result, the raw material fullerene C ₇₀₊ used as a result can be converted to the desired fullerene C ₆₀ with high selectivity and high yield.

This dehydrogenation reaction can be carried out directly on the product of the hydrogenation reaction, or may be carried out after subjecting the product to an appropriate separation operation. That is, if necessary, the solvent, the catalyst, the impurities, etc. may be separated and removed, or the hydrogenated fullerene C ₆₀ may be separated and recovered, and dehydrogenation may be performed thereon. Alternatively, hydrogenated fullerene C ₆₀ and other hydrogenated fullerenes separated and recovered as a mixture with the (raw hydrogenation is hydrogenated product of fullerenes C ₇₀₊ fullerene C _70+, etc.), to the mixture hydrogenated fullerene Alternatively, dehydrogenation may be performed, and various modes can be selected depending on the case.
In the case of separating the insoluble solid matter such as a solid catalyst or insoluble impurities, this can be easily carried out, for example, by filtration or centrifugation, and when separating and removing the solvent,
This can be easily done by conventional techniques such as distillation (evaporation). For example, when a complex catalyst is used as a hydrogenation catalyst and is removed, a method in which it is converted into an insoluble solid residue by successfully decomposing it and then removed by filtration or centrifugation is also suitably adopted. ..

In any case, at least the hydrogenated fullerene C ₆₀ produced from the raw material fullerene C ₇₀₊ or the hydrogenation mixture containing the same is dehydrogenated.

As the dehydrogenation method, at least the hydrogenated fullerene C ₆₀ is sufficiently selected with sufficient selectivity.
There is no particular limitation as long as it can be converted into ₆₀ , and any method may be used. For example, various catalysts such as the above-mentioned hydrogenation catalyst may be used as the catalyst for this dehydrogenation reaction, or, for example, a few catalysts may be used.
-Dichloro-5,6-dicyanobenzoquinone (DDQ)
A stoichiometric organic dehydrogenating agent such as or a stoichiometric inorganic dehydrogenating agent such as lead tetraacetate or mercury (II) acetate may be used, or a combination thereof may be used.

The amounts of these dehydrogenation catalysts and dehydrogenating agents used are
It cannot be determined uniformly because it varies depending on the type and also depends on other conditions such as the degree of hydrogenation of the hydrogenated fullerenes to be dehydrogenated and the reaction temperature, but the amount used is preliminary experiments and calculations. Can be easily determined by.

This dehydrogenation reaction can be carried out in various solvents that do not interfere with the dehydrogenation reaction. For example, cyclohexanes such as hydrogenated products of aromatic compounds used in the hydrogenation reaction, benzene, Aromatic hydrocarbons such as toluene and xylene, etc., and further various kinds of single or mixed solvents such as a mixed solvent of cyclohexanes and aromatic hydrocarbons can be used. Of these, aromatic hydrocarbon solvents such as benzene, toluene and xylene, or mixed solvents containing these as the main components are preferably used from the viewpoint of the efficiency of the dehydrogenation reaction. Such aromatic hydrocarbons are
It has the advantages that the contact efficiency of the reaction is increased and that it is not dehydrogenated by a dehydrogenating agent, and that it is also highly soluble in the fullerenes produced by dehydrogenation, so that it can be used in subsequent fullerenes. It is also suitable for separation and recovery of fullerenes such as C ₆₀ .

The reaction temperature of the dehydrogenation reaction is usually in the range of room temperature to 300 ° C., preferably 50 to 250 ° C. At that time, a method of controlling the reaction temperature by refluxing the solvent is also suitably adopted. If the temperature is lower than room temperature, the reaction generally proceeds slowly or requires cooling, which is disadvantageous in terms of process. On the other hand, if the temperature exceeds 300 ° C., it is difficult to control the reaction because side reactions occur simultaneously. It is easy to cause problems such as.

The reaction time of this dehydrogenation reaction varies depending on other conditions such as the reaction temperature and the type of dehydrogenating agent, but is usually
It is sufficient to set it for about 1 to 10 hours.

[0038] By the above dehydrogenation reaction can be converted to the fullerene C ₆₀ of interest with high selectivity at least hydrogenated fullerene C ₆₀ and conversion. When the raw material for this dehydrogenation reaction contains hydrogenated fullerenes other than hydrogenated fullerene C ₆₀ , these are also dehydrogenated to the corresponding fullerenes, so at least the obtained fullerenes If necessary, fullerenes having 70 or more carbon atoms can be recycled as a raw material for the hydrogenation step. In order to improve process efficiency,
It is desirable to at least quantitatively convert hydrogenated fullerene C ₆₀ to fullerene C ₆₀ .

In this way, a dehydrogenation product containing fullerene C ₆₀ or fullerene C ₆₀ and other fullerenes (eg, fullerene C ₇₀₊ such as fullerene C ₇₀ ) can be efficiently obtained. These are high-purity fullerene C ₆₀ , which is obtained by appropriately removing unnecessary components such as impurities and solvents derived from the catalyst and the dehydrogenating agent as needed.
And fullerenes C ₆₀ as a main component can be recovered as mixed fullerenes. The desired fullerene can be easily separated and recovered by various methods such as known separation methods.

For example, when a sufficient amount of aromatic hydrocarbon is used as the solvent for the dehydrogenation reaction and the fullerenes formed, the dehydrogenating agent and the decomposition products thereof are also dissolved, the solution may be used as it is or after dehydration. The fullerene with the lowest solubility is selected by appropriately concentrating the solution after separating the base material and its decomposed product, for example, by washing with water and transferring to the aqueous phase, or when these are solids, by separating them by filtration, etc. Is preferably used, for example, a method of separating the fullerenes by evaporation or the like, or a method of separating fullerenes as their evaporation residue by sufficiently distilling off low boiling substances such as a solvent. However, it is not limited to these,
Various methods can be used.

On the other hand, when the solvent for dehydrogenation used has low solubility only in fullerenes such as fullerene C ₆₀ , for example, dehydrogenation may be carried out directly from the reaction mixture or after appropriate concentration, if necessary. A method in which the agent and its decomposed product are removed by washing with water and the like, and then the precipitate of the desired fullerenes is separated by, for example, filtration is also suitably used.

The fullerene C ₆₀ thus separated
If necessary, the fullerene-containing fullerene may be washed with an appropriate solvent, extracted, recrystallized, or subjected to a further purification separation operation to obtain a fullerene C _{60 having a} higher purity or a fullerene C _{60 having a} higher purity. Can be recovered as mixed fullerenes having a high degree of purification, and fullerenes other than fullerene C ₆₀ can be isolated and used effectively as necessary. Further, when fullerene C ₇₀₊ remains in the product obtained by the dehydrogenation, it is effective for fullerene C ₆₀ by using this product again as the raw material or raw material component of the hydrogen reaction. Can also be converted into a fullerene C ₆₀ , and the yield of fullerene C ₆₀ can be further improved.

Of course, the fullerene C ₆₀ and the fullerene C _60- containing mixed fullerenes thus obtained can be recovered in a solution state and used as a product.

As described in detail above, by the method of the present invention, more useful fullerene C ₆₀ can be obtained with good selectivity from fullerene having 70 or more carbon atoms, which is not so important in industry. Also, hydrogenated fullerene C ₆₀ can be obtained as an intermediate product in the method of the present invention, and hydrogenated fullerene other than C ₆₀ as a by-product thereof can also be obtained.

Various products such as these fullerene C ₆₀ are effectively used in a wide range of applications, for example, as raw materials for superconductors, various electric and electronic materials, and various derivative synthetic raw materials. Can be used.

[0046]

The present invention will be described in more detail below with reference to examples of the present invention and comparative examples thereof, but the present invention is not limited to these examples.

Example 1C₇₀(Purity 98%, Impurity toluene 2%) 200 mg
Dissolve in 500 ml of toluene and use 5% ruthenium as a hydrogenation catalyst.
Add 5.0 g of thenium / carbon (50% wet)
And hydrogen pressure 50kg / cm²G, temperature at 180 ° C at 2:00
Reacted for a while. When the mass spectrum of the reaction solution was measured
The product is C₇₀Which is a hydrogenated compound of ₇₀H_Ten~ C₇₀
H₄₂Peaks and C₆₀Thought to be a hydrogenated compound of
C₆₀H₁₈~ C₈₀H₄₂Was measured. The compound
The composition of C₇₀25% of the component due to₈₀Originated in
The attributable component was 75%. The yield of these hydrogenated compounds
The amount was 121 mg. Then this mixture of hydrogenated compounds
Is dissolved in 100 ml of toluene, and DD is used as a dehydrogenating agent.
Q (2,3-dichloro-5,6-dicyanobenzoquino
3.0 g), and the mixture was reacted under reflux for 3 hours. Anti
When the reaction solution was separated with a neutral alumina column, C₆₀84
mg and C₇₀25 mg was obtained.

Example 2 200 mg of C ₇₀ (purity 98%, impurity toluene 2%) was dissolved in 500 ml of toluene, 5.0 g of 5% ruthenium / carbon (50% wet) was added as a hydrogenation catalyst, and hydrogen pressure was added. 120 kg / cm ² G, temperature 180 ° C 6
Reacted for hours. Was subjected to mass spectroscopy of the reaction solution, the product is hydrogenated compound of C ₇₀ C ₇₀ H ₁₀ ~C
₇₀ peak of C ₆₀ H ₃₈ ~C ₆₀ H ₆₂ believed hydrogenated compound of a peak considered to H ₃₈ and C ₆₀ were measured. The composition of the compound had a trace amount of components attributed to C ₇₀ and 100% of components attributed to C ₆₀ . The yield of these hydrogenated compounds was 115 mg. Next, the mixture of the hydrogenated compounds was dissolved in 100 ml of toluene, and D was used as a dehydrogenating agent.
3.0 g of DQ (2,3-dichloro-5,6-dicyanobenzoquinone) was added, and the mixture was reacted under reflux for 3 hours. When the reaction solution was separated with a neutral alumina column, C ₆₀ 10
5 mg was obtained and only a small amount of C ₇₀ was observed.

Comparative Example 1 C ₇₀ (purity 98%, impurity toluene 2%) 200 mg was dissolved in 500 ml toluene, 5% ruthenium / carbon (50% wet) 5.0 g was added as a hydrogenation catalyst, and hydrogen pressure was added. The reaction was carried out at a temperature of 180 ° C. for 2 hours at 20 kg / cm ² G. Was subjected to mass spectroscopy of the reaction solution, C ₇₀ H ₃₀ -C ₇₀ product is hydrogenated compound of C ₇₀
Peak of C ₆₀ H ₃₂ ~C ₆₀ H ₄₄ believed hydrogenated compound of peaks and C ₆₀ considered H ₄₀ were measured. The composition of the compound was such that C ₇₀ accounted for 60% and C ₆₀ accounted for 40%. The yield of these hydrogenated compounds was 125 mg. Next, the mixture of the hydrogenated compounds was dissolved in 100 ml of toluene and DD was used as a dehydrogenating agent.
3.0 g of Q (2,3-dichloro-5,6-dicyanobenzoquinone) was added and reacted under reflux for 3 hours. When the reaction solution was separated with a neutral alumina column, C ₆₀ 42
mg and C ₇₀ 64 mg were obtained.

In this case, the hydrogenation reaction is carried out at 20 kg / c.
Since the hydrogen partial pressure is as low as m ² , C ₇₀ to C
_{Although 60} can be obtained, its selectivity is low, which is an insufficient method for obtaining C ₆₀ from C ₇₀ .

[0051]

INDUSTRIAL APPLICABILITY According to the present invention, fullerene C _{70 and} other high molecular weight fullerenes having a carbon number of 70 or more are converted into fullerene C.
It is possible to provide a method for converting ₆₀ into a compound with high selectivity and efficiency. That is, the method of the present invention, the fullerenes (C ₇₀₊₎ more useful and highly important fullerene C ₆₀ from the industrial importance less carbon atoms 70 or more high molecular weight as compared to the fullerene C ₆₀ acids efficiency It can be manufactured well, and can significantly contribute to the improvement of the productivity of fullerene C ₆₀ or its derivative.

Claims (1)

[Claims] 1. A high-molecular weight fullerene having a closed shell structure having a carbon number of 70 or more in the presence of a hydrogenation catalyst at a hydrogen pressure of 30.
A process for the selective conversion of high molecular weight fullerenes to C ₆₀ , which comprises hydrogenating under the conditions of ˜180 kg / cm ² G and a temperature of 80 to 240 ° C., and then dehydrogenating the obtained hydride.