JPH11240705A - Separating agent for fullerene and purification of fullerene by using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a separating agent for fullerene, capable of being readily produced and easily available, and capable of efficiently separating the fullerene from a fullerene mixture, and further to provide a method for purifying the fullerene by using the separating agent. SOLUTION: This separating agent for fullerene is a cyclic phenol sulfide of the formula [Y is H, an alkyl, a halogenated alkyl, a halogen atom, nitro, an alkoxy or an acyl; (n) is 4-8]. A fullerene mixture is brought into contact with the separating agent in a solution to provide an inclusion complex of the cyclic phenol sulfide and the fullerene and the obtained inclusion complex is separated in the method for purifying the fullerene.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention is a mixture of fullerenes containing fullerenes such as C _60, fullerene fullerene using fullerene separating agents comprising the cyclic phenol sulfide and which can be separated as inclusion complexes It relates to a purification method.

[0002]

BACKGROUND ART Fullerenes are a so-called soccer ball molecule spherical composed of only carbon atoms, To do this, including the C _60, include those having a carbon number of C ₇₀ or higher. The C ₆₀ Kroto and Smalle
Since their discovery, these fullerenes have been
Many derivatives have been synthesized, such as various derivatives obtained by functionalizing fullerene itself, metal complexes having fullerene as its ligand, composite compounds with a polymer, or compounds containing a metal inside a sphere. Furthermore, researches on applied fields such as superconducting compounds and medical applications have been actively conducted, and high expectations are placed on new functional molecules. A large amount preparation of C ₆₀ is, was discovered in 1990 by Huffman et al. Generally, fullerenes, but are like the soot produced by arc discharge of graphite, as described above, including the C _60, include those having a carbon number of C ₇₀ or higher.

Therefore, in order to selectively obtain specific fullerenes, it is necessary to selectively separate and purify specific fullerenes from the mixture of fullerenes, and much research and development has been conducted on this separation and purification method. ing. Conventionally, as this separation and purification method, there is a method using column chromatography, but there are problems that the recovery rate is low and that it is not suitable for treatment on a large scale. Recently, Atwood and Shinkai et al., Found the precipitation of C ₆₀ by using the calix [8] arene, have reported (e.g., Nature (London), 19
94, 368, 229 and JP-A-7-237911. Further, Fukasawa et al ligated to two molecules of calix [5] arene, and synthesizing receptor C ₆₀ and C ₇₀ (Angew.Chem.Int.Ed.Engl.
1997, 36, 259). Although recovery and purity of C ₆₀ purified by these methods are improved compared with those by column chromatography, room for improvement in the purification of fullerene having carbon numbers greater than the recovery rate and purity or C ₇₀ It is said that there is. Further, the synthesis of calixarene used as a receptor was not always a simple method.

[0004]

The problem to be solved by the present invention is that it has a new structure which has never existed in the prior art, is simple in its production method, is easy to obtain, and efficiently converts fullerene from a mixture of fullerenes. And a method for purifying fullerene using the same.

[0005]

The present inventors have previously found a group of cyclic phenol sulfides containing three or more phenol skeletons in the basic skeleton (JP-A-9-227553). It has been found that the compound group is useful as a metal supplement, an ion sensor, an optical isomer separation material, a collecting agent for organic halogen compounds, or an intermediate of other functional molecules utilizing ions or molecular recognition. The present inventors have paid attention to the molecular inclusion properties of the cyclic phenol sulfide, and as a result of intensive studies, have found that the general formula (1)

[0006]

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(In the formula (1), Y is a hydrogen, an alkyl group, a halogenated alkyl group, a halogen atom, a nitro group, an alkoxyl group or an acyl group, and n is an integer of 4 to 8.) The present inventors have found that cyclic phenol sulfide forms an inclusion complex with fullerene, thereby completing the present invention. That is, the present invention provides a compound represented by the general formula (1) (wherein Y is a hydrogen, an alkyl group, a halogenated alkyl group, a halogen atom, a nitro group, an alkoxyl group or an acyl group, and n is 4 to 8). And a cyclic phenol sulfide represented by the following formula: In the present invention, the general formula (1) (wherein, Y is hydrogen, an alkyl group, a halogenated alkyl group, a halogen atom, a nitro group, an alkoxyl group or an acyl group, and n is 4 to 8)
Is an integer. A method for purifying fullerenes, comprising contacting a mixture of a cyclic phenol sulfide represented by the formula (1) and a fullerene in a solution to form an inclusion complex of the cyclic phenol sulfide and the fullerene, and separating the resulting mixture. Is provided. The present invention also the n in the general formula (1) is a mixture of fullerenes containing cyclic phenol sulfide tetramer and C ₆₀ is a 4 by contacting in solution, the cyclic phenol sulfide and the C ₆₀ An object of the present invention is to provide a method for purifying fullerene, which comprises forming an inclusion complex and separating it. Hereinafter, the present invention will be described in detail.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The cyclic phenol sulfide used in the present invention is represented by the general formula (1). General formula (1)
Is a hydrogen, an alkyl group, a halogenated alkyl group, a halogen atom, a nitro group, an alkoxyl group or an acyl group. The number of carbon atoms of the alkyl group is not particularly limited as long as it is 1 or more, but is preferably 12 or less, more preferably 6 or less. Examples of the halogenated alkyl group include those in which a halogen atom is substituted for the same alkyl group as described above, and preferable ones are also the same. The halogen atom may be any of a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

The carbon number of the alkoxyl group is not particularly limited as long as it is 1 or more, but is preferably 1 to 6. The number of carbon atoms in the acyl group is not particularly limited as long as it is 1 or more, but is preferably 1 to 7. In general formula (1), there are a plurality of Y's, and these Y's may be the same or different. N in the general formula (1) is an integer of 4 to 8. Next, a method for producing the cyclic phenol sulfide represented by the general formula (1) will be described. A production example of the cyclic phenol sulfide of the general formula (1) is disclosed in JP-A-9-22755.
No. 3 is described in the specification. Suitable manufacturing examples include
First, general formula (2)

[0010]

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(In the general formula (2), Y ¹ is an alkyl group.) An alkylphenol having an alkyl group at the 4-position and an appropriate amount of elemental sulfur are mixed with an appropriate amount of an alkali metal reagent and an alkali. This is a method in which the reaction is performed in the presence of at least one metal reagent selected from earth metal reagents. The raw material charge ratio of alkylphenols and elemental sulfur is 0.1 g of alkylphenols and 0.1 g of elemental sulfur.
It is at least gram equivalent, preferably at least 0.35 gram equivalent. The upper limit of the raw material charging ratio of elemental sulfur is not particularly limited, but for 1 gram equivalent of alkylphenols,
It is preferably at most 20 gram equivalent, particularly preferably at most 10 gram equivalent.

The alkali metal reagent includes, for example, a simple alkali metal, an alkali metal hydride, an alkali metal hydroxide, an alkali metal carbonate, an alkali metal alkoxide, an alkali metal halide and the like. Examples of the alkaline earth metal reagent include, for example, alkaline earth metal alone, alkaline earth metal hydride, alkaline earth metal hydroxide, alkaline earth metal oxide, alkaline earth metal carbonate, alkaline earth metal alkoxide, and halogen. Alkaline earth metal and the like. The amount of the alkali metal reagent or alkaline earth metal reagent used is 0.005 gram equivalent or more, preferably 0.01 gram equivalent or more, per 1 gram equivalent of the alkylphenol. The upper limit of the amount of the alkali metal reagent or alkaline earth metal reagent used is not particularly limited, but is preferably 10 gram equivalent or less,
Particularly preferably, it is not more than 5 gram equivalent.

The mixture of fullerenes, which is a raw material used in the method for purifying fullerenes of the present invention, is a mixture of two or more fullerenes selected from fullerenes such as C ₆₀ , C ₇₀ and fullerenes having more carbon atoms. it may be, or may be a mixture of C _60, C ₇₀ and higher of one or more fullerenes and other components other than fullerene selected from fullerene such as fullerene having carbon numbers. In the method for purifying fullerene of the present invention, the general formula (1)
In a solution to form an inclusion complex of the cyclic phenol sulfide and the fullerene, which is separated. This allows
Fullerene can be purified. The contact between the cyclic phenol sulfide and the mixture of fullerenes in a solution may be performed by adding the cyclic phenol sulfide or a solution thereof to the solution in which the mixture of fullerenes is dissolved, or the cyclic phenol sulfide is dissolved. It may be carried out by adding a mixture of fullerenes or a solution thereof to the solution, but the former is preferred.

The solvent for dissolving the mixture of fullerenes and cyclic phenol sulfide includes, for example, benzene, toluene, xylene, ethylbenzene and the like.
The amount of the cyclic phenol sulfide to be used is not particularly limited, except that the upper limit is limited by the solubility in these solvents. Although the solubility differs depending on the type of the cyclic phenol sulfide, the cyclic phenol sulfide in which Y is an alkyl group in the general formula (1) generally has high solubility in toluene and xylene. In the case of benzene, precipitation of the inclusion complex occurs around room temperature. Therefore, considering conditions such as the composition ratio of the fullerene mixture,
What is necessary is just to select suitably. The amount of the cyclic phenol sulfide to be used with respect to the mixture of fullerenes is not particularly limited, but is preferably equal to or more than the molar amount of fullerenes for efficient purification. Conversely, it is inefficient to use a large amount as compared to fullerene.

When the mixture of the cyclic phenol sulfide and the fullerene is brought into contact in a solution, the solution may be stirred or the solution may be allowed to stand. The mixing time is not particularly limited, and varies depending on the concentration of fullerene and cyclic phenol sulfide in the solution and the temperature of the solution. Usually, when the concentration of fullerene and cyclic phenol sulfide in the solution is low, the formation of the inclusion complex requires a long time. The mixing temperature is not particularly limited as long as it is equal to or lower than the boiling point of the solvent.
What is necessary is just to carry out at about 75 degreeC.

The ability to form an inclusion complex with fullerene varies depending on the type of cyclic phenol sulfide. For example, in the case of cyclic phenol sulfide wherein n is 4 in the general formula (1), a high ability to form a C ₆₀ inclusion complexes. Accordingly, the general formula of a mixture of fullerenes n comprises a cyclic phenol sulfide and C ₆₀ is a 4 in (1) contacting in solution, to produce an inclusion complex with the cyclic phenol sulfide and C _60, which Is separated, C ₆₀ can be selectively separated. The generated inclusion complex can be separated by various separation means. Usually, the inclusion complex forms as a precipitate in the solution. If necessary, a precipitate may be formed by stirring or cooling the solution below the freezing point. In this case, the sediment can be separated by ordinary separation means such as filtration and centrifugation. Fullerene can be recovered from the precipitate by dispersing the precipitate in an organic halogen-based solvent. Thereby, the clathrate complex is decomposed, and only fullerene can be precipitated from the clathrate complex. Examples of the organic halogen-based solvent include chloroform, carbon tetrachloride,
Examples include methylene chloride and tetrachloroethane, and preferably chloroform.

[0017]

EXAMPLES The present invention will be described in more detail with reference to Examples. However, the present invention is not limited by these examples.

Production Example 5,11,17,23-Tetra-tert-butyl-2
5,26,27,28-tetrahydroxy-2,8,1
4,20- Tetorachia [19.3.1.1 ^3,7 1 ^9,13 1
^15,19 ] octacosa-1 (25), 3,5,7 (2
8), 9, 11, 13 (27), 15, 17, 19 (2
6) Synthesis of 21,23-dodecaene (I) To 45.2 g of 4-tert-butylphenol, 14.4 g of elemental sulfur and 3.0 g of sodium hydroxide were added.
In a nitrogen stream, with stirring, gradually increase to 230 over 4 hours.
C. and continued stirring for another 2 hours. During this time, water and hydrogen sulfide generated by the reaction were removed. About 0.8 g of water was distilled off during the reaction, and about 6 g of hydrogen sulfide was produced by the reaction. The reaction mixture was cooled to room temperature, dissolved by adding 500 ml of ether, and hydrolyzed with a 1N aqueous sulfuric acid solution. The reaction mixture obtained by distilling ether from the separated ether layer was further separated by silica gel chromatography (hexane / chloroform) to obtain a crude product, which was recrystallized from chloroform / acetone. 5,11,17,23-tetra-tert-butyl-2 which is a colorless and transparent crystal
5,26,27,28-tetrahydroxy-2,8,1
4,20- Tetorachia [19.3.1.1 ^3,7 1 ^9,13 1
^15,19 ] octacosa-1 (25), 3,5,7 (2
8), 9, 11, 13 (27), 15, 17, 19 (2
6), 4.32 g of 21,23-dodecaene were obtained.
This is because in the general formula (2), n = 4 and Y = t
Cyclic phenol sulfide which is -butyl.

Example 1 2 g of commercially available soot (fullerene content: about 10% by mass) was dissolved in 400 ml of distilled toluene, irradiated with ultrasonic waves at room temperature, and the insoluble matter was filtered. After the solvent was distilled off from the obtained filtrate, the residue was dried under reduced pressure to obtain 0.919 g of a fullerene mixture. When the obtained fullerene mixture was analyzed by HPLC, the molar ratio was as follows. C ₆₀ 100; C ₇₀ 22.6; C ₇₆ + C
_{78 0.9; C 82 + C 84} 0.95; C 86 0.24;
C ₈₈ + C ₉₀ + C ₉₂ 1.4; C ₉₄ 0.078 17.7 mg of this fullerene mixture was added to 10 m of benzene.
l. 70 mg of the cyclic phenol sulfide (I) obtained according to the preparation example was added to this solution at room temperature,
Heated at ° C for 10 minutes. 10 ° C. while stirring this solution
And left at this temperature for 10 minutes. The precipitate collected by centrifugation was 28 mg. Each of the supernatant and the precipitate was subjected to quantitative analysis. The precipitate was washed with a small amount of benzene, dried, and then washed with chloroform to remove the cyclic phenol sulfide (I). The remaining fullerene was dissolved in o-dichlorobenzene, and analyzed by HPLC. As a result, the concentration of C _{60 in} the supernatant was 23% of the concentration in the mixture of the raw material fullerene.
It was found that 77% of C ₆₀ was recovered. Further, the purity of the C ₆₀ in the precipitate was 82%.

[0020]

According to the present invention, fullerenes can be efficiently separated or purified.

Continuing on the front page (72) Inventor Yosuke Nakamura 3-1-5 Hakozaki, Higashi-ku, Fukuoka, Fukuoka Prefecture Domi Espoir Hakozaki V501 (72) Inventor Atsushi Nishimura 717-1 Ogo, Ogo-cho, Seta-gun, Gunma Prefecture (72) Invention Person Hitoshi Kumagai 1134-2 Gongendo, Satte City, Saitama Prefecture Inside the R & D Center, Kosmo Research Institute, Inc. (72) Inventor Setsuko Miyanari 1134-2 Gongendo, Satte City, Saitama Prefecture, the R & D Center of Kosmo Research Institute, Inc.

Claims (3)

[Claims] 1. A compound of the general formula (1) (In the formula (1), Y is hydrogen, an alkyl group, a halogenated alkyl group, a halogen atom, a nitro group, an alkoxyl group, or an acyl group, and n is an integer of 4 to 8.) A separating agent for fullerene, comprising a sulfide. 2. A method comprising contacting a mixture of a cyclic phenol sulfide of the general formula (1) and fullerene in a solution to form an inclusion complex of the cyclic phenol sulfide and fullerene, and separating the complex. Fullerene purification method. 3. a mixture of fullerenes containing cyclic phenol sulfide tetramer and C ₆₀ is n in the general formula (1) 4 is contacted with a solution, the cyclic phenol sulfide and C ₆₀
A method for purifying fullerene, which comprises forming an inclusion complex with the compound and separating the same.