JP3402521B2 - Filler for liquid chromatography, method for producing the same, and method for separating fullerenes using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel packing material for liquid chromatography and a method for producing the same, and more particularly to a packing material for liquid chromatography having a structure in which the retention power for fullerenes can be advantageously increased. Regarding the method. The present invention also relates to a method for separating fullerenes using such a packing material for liquid chromatography.

[0002]

BACKGROUND ART Conventionally, a liquid chromatography method can be applied to a wide range of separation conditions, and it is not necessary to expose a sample to high temperatures, and even under low temperature conditions such as room temperature,
Since compounds can be separated, they have been widely used for purification and separation of various compounds ranging from biological substances to organic compounds in general. Since the separation ability of substances by this liquid chromatography method is greatly affected by the packing material packed in the column, the mobile phase solvent used, etc., the liquid chromatography can be performed by selecting these packing material, mobile phase solvent, etc. It is possible to enhance the resolution of compounds by the graphic technique.

On the other hand, fullerenes are one of the materials that have recently been attracting attention as a substance separated and purified by a liquid chromatography method. The fullerenes are, as represented by C ₆₀ , C _70, etc., a simple substance composed of only carbon atoms, or a compound group having various functional groups bound to the simple substance as a basic skeleton. It is a new substance that is expected to have new functions that can be applied to fields such as superconductors, ferromagnetic substances, lubricating oils, and semiconductors.

By the way, these fullerenes are produced together with soot generated during arc discharge or resistance heating of a graphite rod and are separated from the soot by extracting the soot with an aromatic hydrocarbon solvent such as toluene. ing.
Therefore, at present, since the technology for synthesizing only a single type of fullerene has not been established, the allotropes of various fullerenes are contained in the toluene extraction solution of the soot. It is necessary to separate and purify each allotrope in order to exert the useful function. However, fullerenes are very high in allotropes or isomers having similar properties, are high melting point substances, and may change to other allotropes under high temperature conditions. Therefore, it is difficult to isolate the compound by a purification method such as distillation, recrystallization, sublimation, etc. which is often used for the purification of a compound. Therefore, for the separation and purification of such fullerenes, the separation ability is excellent, and it is possible to separate the fullerenes under mild conditions,
Separation using liquid chromatography techniques is expected.

However, such fullerenes have the solubility of C ₆₀ (20 ° C.) in an organic solvent as shown in Table 1 below.
Separation using liquid chromatographic techniques because it can be poorly dissolved in most solvents, as shown in
In particular, it is one of those that are difficult to separate for the purpose of purification. That is, when separating and purifying fullerenes by a liquid chromatography method, as a mobile phase solvent, fullerene is relatively well dissolved, in other words, when using an aromatic hydrocarbon or the like having a large elution power, With the filler used, the holding power for the fullerenes is weak and the fullerenes cannot be sufficiently held, so that the separation cannot be sufficiently performed,
Conversely, it is difficult to dissolve fullerenes as a mobile phase solvent,
In other words, when a solvent having a low elution output is used, it is hardly dissolved in the mobile phase solvent (separation solvent) due to the low solubility of fullerenes in the solvent, and it is difficult to perform liquid chromatography itself. It will be.

[0006] * Literature value: N. Sivaraman, et al, "J. Org. Chem.", 57, 6077-6079, (1992). (25 ° C)

Under these restrictions, currently, in the separation and purification of fullerenes, a mobile phase solvent containing hexane as a main component is used, while a column packing material is an octadecylsilyl group-introduced type. Filler (hereinafter, C1
Fillers such as silica gel, alumina, etc. are used. However, in order to efficiently separate and purify fullerenes, it is desirable to add as many fullerenes as possible to the separation column, but the solubility in hexane, which is the main component of the mobile phase solvent, is low. However, there is an inherent problem that a large amount of sample solution needs to be injected, which causes broadening of the peak band, resulting in insufficient separation. Further, in order to solve this problem, a solvent having a relatively high solubility such as toluene, which can dissolve a large amount of a fullerene mixture in a small amount, may be used. Since the elution output of is very large compared to the retention of the fullerene by the packing material, the fullerene is eluted from the column before being separated, and the peak shape is significantly deteriorated. Thus, under the present circumstances, it is difficult to separate a large amount of fullerenes with a solvent having a small elution power or a solvent having a large elution power.

That is, in the separation and purification of fullerenes by a liquid chromatography method, when a conventional packing having only a weak retention power is used, toluene, which is a solvent having a large dissolution output for fullerenes, is completely removed. It is indispensable to perform complicated operations such as distilling off to a sample solution containing only hexane, which has a small elution output, and
Even if such a complicated operation is performed, it is difficult to separate a large amount of fullerenes at once.
And, in order to prevent the reduction of resolution due to the spread of the peak band due to the injection of a large volume of sample solution, a larger column is required when separating fullerenes than when separating general compounds. There are inherent problems such as

[0009] On the other hand, it has been reported that pyrene is bonded to a filler so that fullerenes can be separated by a liquid chromatography method even when toluene is used as a mobile phase solvent. However, even with such a filler,
The solubility of fullerenes is higher than that of toluene, and when carbon disulfide, which is advantageous for separating a large amount of fullerenes at the same time, is used as a mobile phase solvent, fullerenes elute without being separated, Even with such a filler, it is difficult to say that it still has sufficient holding power.

As described above, the reason why separation of fullerenes by the liquid chromatography method is difficult is that the retention capacity for fullerenes in the existing packing is extremely weak as compared with the dissolution output by the mobile phase solvent. It is thought to be due to. Therefore, there is a demand for the development of a packing material having a strong retention force, which can obtain a sufficiently satisfactory result in the liquid chromatographic separation of fullerenes.

[0011]

The present invention has been made in view of such circumstances, and its object is to provide a substance that is hardly soluble in a general mobile phase solvent such as fullerenes. A packing material for liquid chromatography, which has a retention force such that the substance can be sufficiently separated even when it is separated by a liquid chromatography method using a solvent having a large elution output (solubility) as a mobile phase solvent; It is an object of the present invention to provide an advantageous production method thereof, and also to provide a method of advantageously separating fullerenes by using such a packing material for liquid chromatography.

[0012]

In order to solve such a problem, the present inventor has conducted an earnest search for a functional group having an excellent coercive force, and as a result, a solvent having a structure having a specific halogen in the molecule has been found. It was found that the solvent has a large elution output for fullerenes, which indicates that a solvent having a large elution output for the same filler also has a large affinity for the solute fullerenes. It is considered that by applying a solvent having a structure having a specific halogen in the molecule to the filler, that is, by binding a compound having a structure having the specific halogen in the molecule to a carrier constituting the filler. , It was concluded that a filler having a higher holding power for fullerenes can be obtained. Therefore, in order to demonstrate this reasoning, we synthesized a packing material to which a functional group substituted with a specific halogen was bound, and used this as a packing material (stationary phase) for liquid chromatographic separation of fullerenes. As a result, even when carbon disulfide, which has a larger elution power than toluene, was used as the mobile phase solvent, it had a sufficiently strong retention force to enable sufficient liquid chromatography separation. It was found to show.

The present invention has been completed based on such findings, and the gist of the present invention is to provide an aromatic functional group having a total of three or more bromine and / or iodine bonded to an aromatic ring. In the packing material for liquid chromatography, the packing material is composed of a carrier chemically modified by.

According to an advantageous embodiment of such a packing material for liquid chromatography according to the present invention, the aromatic functional group is chemically bonded to the carrier via an oxyalkylsilyl group. According to another advantageous embodiment, silica gel is used as the carrier.

Further, the present invention uses a silylating agent having an aromatic functional group in which a total of three or more bromine and / or iodine are bonded to an aromatic ring, and the silylating agent is a hydroxyl group on the surface of a carrier. A method for producing a packing material for liquid chromatography, characterized in that the stationary phase having the aromatic functional group is formed on the surface of the carrier by reacting with the carrier, is also the gist thereof, and a desirable embodiment thereof According to the above, silica gel is used as the carrier.

Further, in the present invention, when separating fullerenes by a liquid chromatography method, a chemical reaction is carried out with an aromatic functional group formed by binding at least three bromine and / or iodine in total to an aromatic ring. A gist of the present invention is also a method for separating fullerenes, which is characterized by using a filler composed of a modified carrier.

In the method for separating fullerenes, carbon disulfide is preferably used as the mobile phase solvent.

[0018]

[Specific Structure / Operation] As described above, according to the present invention,
The liquid chromatography packing material is chemically modified with an aromatic functional group (hereinafter, referred to as brominated / iodinated aromatic functional group) in which three or more bromine and / or iodine are bonded to the aromatic ring in total. Liquid chromatographic separation using a packing material having such a structure, the separation force is insufficient due to insufficient retention when using a conventional packing material. A mixture containing isomers and allotropes that were difficult to achieve,
In particular, effective separation of fullerenes has become possible.

Incidentally, the filler according to the present invention may be in any form as long as it has the above-mentioned brominated / iodinated aromatic functional group, but in general, ArX _n -A-O-carrier material (however, ArX _n: bromination / iodinated aromatic functionality,
A: A spacer group) is a chemical bond type filler.

The brominated / iodinated aromatic functional group is bound via a predetermined spacer group (A) to give a desired filler as a carrier material. Any known carrier material can be used as long as it can retain an aromatic functional group by being chemically bound thereto. In producing such a filler, it is well known as a general method for producing a filler. When a chemical modification method using an organic silicon compound (silylating agent) is used, porous glass, glass beads, alumina, titania, zirconia, etc. may be appropriately used in addition to silica gel. . However, considering the surface area of the carrier material and the reactivity of the silylating agent with the hydroxyl groups on the carrier surface, silica gel is preferably used among the above carriers.

The silylating agent reacts not only with the hydroxyl groups present on the surface of the inorganic carrier material, but also with the alcoholic hydroxyl groups present in the organic carrier. The reaction between the silylating agent and the alcoholic hydroxyl group forms an alkoxysilane (Si-O-R), and the bond is easily hydrolyzed, so that the water-alcohol mixed solvent is used as the mobile phase solvent. It can not be used under various conditions, but when liquid chromatography is performed under conditions that do not use water or alcohol as the mobile phase solvent, polystyrene gel,
It is also possible to use an organic polymer gel such as polyvinyl alcohol gel or a carrier material based on a polysaccharide such as agarose or cellulose.

As the spacer group represented by A above, which is bonded between the brominated / iodinated aromatic functional group and the carrier material, most of the holding power of the filler for fullerenes is Various known atomic groups can be used because they are expressed in the brominated / iodinated aromatic functional group portion and are hardly affected by the difference in the spacer group. And, as such a spacer group, for example, a straight chain hydrocarbon group such as a methylene group, an ethylene group, a propylene group, and the like, in addition to them, an ether bond, an amide bond, an ester bond, a carbonyl group, and the like, It does not matter even if an atomic group having a functional group containing a sulfur atom or a nitrogen atom introduced therein is used. Then, from the viewpoint of advantageously increasing the coercive force, preferably an oxyalkylsilyl group having a structure in which oxygen is bound to the brominated / iodinated aromatic functional group side, particularly preferably —O—R ₁ —Si (R ₂ ) (R ₃ ) −
(However, R ₁ is an alkylene group having 1 to 4 carbon atoms, R ₂ , R
₃ is hydrogen or an alkyl group having 1 to 4 carbon atoms). Further, here, the structure having a spacer group is exemplified, but the structure is not limited thereto, and the brominated / iodinated aromatic functional group is directly bonded to the carrier material without passing through the spacer group. It doesn't matter what you do.

In the present invention, the chemical modification of the carrier material is carried out with an aromatic functional group having a structure in which a total of three or more bromine and / or iodine are bonded to the aromatic ring. By introducing a brominated / iodinated aromatic functional group having such a structure, the interaction between the fullerene and the filler can be increased, and thus the separation of the fullerene can be effectively performed. As a result of the following examination, it became clear.

That is, first, in Table 2 below, the retention of solute: C ₆₀ given by each filler when various organic solvents are used as mobile phase solvents is shown by using the k ′ value as an index. Generally, when the retention characteristic of a column (filler) is exhibited, the time from the injection of a sample into the column to the top of the peak eluted from the column (retention time) is used. Since the relative evaluation can be performed only when the flow rate of the mobile phase solvent to be sent is the same and the columns used are the same, comparison of columns with different packing materials and column In the case where the size is different, or when the mobile phase solvent feed rate is different, etc., even if the retention times are compared,
It becomes impossible to make relative comparisons. Therefore, in the comparison of the results of the chromatographic separation under different conditions, the value represented by k ′ in the following formula is usually expressed, that is, the ratio of the retention time of the retained compound in the column to the elution time of the unretained solute. Thus, the retention characteristic (retention force) of each solute is evaluated. k ′ = (t _r −t _o ) / t _o

Here, t _{r is} the retention time of the solute, and t _o is the elution time of the solute that is not retained. Further, by using such k'value, it is possible to ignore the influence due to the difference in the length and thickness of the column, the difference in flow rate, etc., and thus it becomes possible to purely evaluate the characteristics of the packing material. is there.

[0026] Generally, the retention of solutes (for example, fullerenes) by the filler increases as the interaction between the solute and the stationary phase bound to the surface of the carrier constituting the filler becomes stronger. However, the difference in retention when different solvents are used in the same filler is that the interaction between the solute and the stationary phase is inhibited by the influence of the interaction between the solute and the solvent. Is thought to be the cause.
That is, when the interaction between the solute and the solvent is stronger than the interaction between the solute and the stationary phase, the solute is more thermodynamically stable when dissolved in the solvent, so that the solute is dissolved in the solvent (mobile phase). Will be dissolved in the column and will be quickly eluted from the column.
For this reason, a solvent having a strong interaction with a solute elutes the solute earlier, and a solvent having a small interaction, on the contrary, elutes the solute later.

Although it is considered that the elution behavior also involves the interaction between the solvent and the stationary phase, in the solvents shown in Table 2 below, the retention of the solvent itself by the stationary phase is not observed. The interaction between the solute and the solvent is very small, and it is considered that only the strength of the interaction between the solute and the solvent should be considered.

[0028] C18: Octadecyldimethylsilylated filler NPE: Nitrophenylethylsilylated filler PYE: Pyrenylethylsilylated filler PYP: Pyrenylpropylsilylated filler Detection wavelength: 285 to 320 nm

Then, examining Table 2 in detail,
Hexane, chlorohexane, when using bromohexane as a mobile phase solvent, from the comparison of the retention force given by each filler, the solvent substituted with chlorine or bromine has the effect of increasing the dissolution output for fullerenes, It is understood that the effect is greater with the bromine substitution than with the chlorine substitution. In addition, by comparing the holding powers when benzene and fluorobenzene were used as mobile phase solvents, it was clear that those substituted with fluorine reduced the leaching output, which was the reverse of those substituted with chlorine or bromine. The result is. That is, it is understood that the greater the atomic number of the halogen element to be bonded, the greater the interaction with the fullerenes. Furthermore, dichloromethane, chloroform, benzene, chlorobenzene,
From the comparison of retentivity when 1,2,4-trichlorobenzene was used as the mobile phase solvent, it was found that as the number of halogens (chlorine in this case) substituting the solvent molecules increased, the halogens also formed on the aromatic ring. The binding enhances the effect of increasing the elution capacity of the fullerenes by these solvents.

In summary, from the above results and consideration thereof, the present inventors have found that the solvent has a large elution power,
By constructing a filler from a carrier chemically modified with an aromatic compound to which bromine and / or iodine is bound, the retention (interaction) of the filler with respect to fullerenes and the like can be advantageously enhanced. Therefore, it has been found that liquid chromatography separation can be effectively performed by using the packing material.

Here, the greater the number of bromine and / or iodine bound, the stronger the interaction with the fullerenes, but the sufficient interaction with the fullerenes. In order to express And, of course, these do not have to be a single kind of element, but may be a combination of bromine and iodine, and are aromatic functional groups substituted with three or more bromine and / or iodine. If there are other substituents such as fluorine and chlorine, and further, a methyl group, a hydroxyl group, and the like, there is no particular problem.

As the aromatic hydrocarbon group which is the basic skeleton of the brominated / iodinated aromatic functional group, any aromatic hydrocarbon group can be adopted as long as three or more bromine and / or iodine are bonded. And, for example,
Examples thereof include a phenyl group, a naphthyl group and a pyrenyl group.

Further, the position of substitution of bromine and / or iodine in the brominated / iodinated aromatic functional group must be on the aromatic ring of the aromatic functional group. However, when bromine and / or iodine are replaced with an aliphatic hydrocarbon bonded to an aromatic ring, the interaction with fullerenes is weakened as compared with the case where they are directly substituted on the aromatic ring, and such aromatic compounds This is because when liquid chromatography is carried out using a carrier modified with a group functional group as a packing material, the retention capacity becomes insufficient and the separation capacity becomes low.

By the way, the amount of the stationary phase (brominated / iodinated aromatic functional group) in the filler according to the present invention affects the retention time of the solute, but generally, when the amount thereof increases, the solute is increased. Interaction with the stationary phase is increased, resulting in increased solute retention. This relationship can be similarly applied to fullerenes, and the use of a filler having a large number of stationary phases bound thereto exerts a strong holding force for fullerenes, and as a result, C ₆₀ and C ₇₀ Can be effectively separated from. That is, it is desirable that as many brominated / iodinated aromatic functional groups as possible be attached to the carrier in order to obtain a filler having a greater retention of fullerenes.

On the other hand, the lower limit of the amount of the stationary phase in the filler according to the present invention varies depending on the conditions and is not unconditionally determined, but generally, the retention force for the target substance is effectively exhibited. It is enough if there is a sufficient amount. Therefore,
The filler according to the present invention, even though the reactivity of the carrier when chemically modified with a brominated / iodinated aromatic functional group that is a stationary phase is somewhat worse than that of a conventional filler. Since the solute holding force of the stationary phase used in (1) is strong, a filler that can be used sufficiently can be obtained. In other words, even when the carrier is chemically modified with a brominated / iodinated aromatic functional group, the reactivity with the brominated / iodinated aromatic functional group is worse than that of a conventional filler. Useful fillers may be obtained, which advantageously extends the choice of carriers to be reacted. Specifically, for example, in the case of a filler having three times the holding power as compared with the conventional filler, even if the amount of the stationary phase of the filler becomes 1/3, it is almost the same as that of the conventional filler. When the amount of the stationary phase is made larger than that, it becomes a useful filler with improved holding power.

The packing material for liquid chromatography according to the present invention can be manufactured by utilizing various known reactions. Generally, 1) silylation having a brominated / iodinated aromatic functional group is carried out. Method of reacting an agent with a carrier, 2) Method of reacting an organometallic compound having a brominated / iodinated aromatic functional group with the carrier, 3) After introducing a functional group having reactivity into the carrier, the functional group is added to the functional group. Brominated / iodinated aromatic functional groups are bonded, 4) after the aromatic hydrocarbon group is bonded to the carrier, the aromatic hydrocarbon group is directly brominated or iodinated. Will be manufactured.

More specifically, in the above method 1) using a silylating agent, first, a substituent having a double bond is introduced into a brominated / iodinated aromatic functional group. Then, the introduction of the substituent having a double bond into the brominated / iodinated aromatic functional group is to introduce a substituent having a double bond such as an allyl group into the brominated / iodinated aromatic functional group. Therefore, specifically, the reaction represented by the following reaction formulas (1a) and (1b) can be advantageously carried out. Here, ArX _n represents a brominated / iodinated aromatic functional group, and the same applies to the following reaction formulas.

ArX _n —Br + HO—CH ₂ —CH═CH ₂ ─── → ArX _n —O—CH ₂ —CH═CH ₂ (1a) ArX _n —OH + Br—CH ₂ —CH _{= CH 2 ─── → ArX n -O} -CH 2 -CH = CH 2 ··· (1b)

Then, at the double bond site of the thus obtained brominated / iodinated aromatic functional group having a double bond, as shown in the following reaction formula (2), a hydrosilane (H- The silylating agent can be obtained by a so-called hydrosilylation reaction in which Si) is added. In this reaction, in the addition reaction of hydrosilane, the anti-Markovnikov type addition mainly proceeds and the silicon atom is bonded to the terminal of the alkene molecule. Such a method has an advantage that a silylating agent having a target structure can be easily obtained because the conversion rate to a silylating agent is large and side reactions are few.

[0040] _{ArX n -O-CH 2 -CH =} CH 2 + H-Si (CH 3) 2 -Cl Pt ─── → ArX n -O- (CH 2) 3 -Si (CH 3) 2 -Cl ... (2)

As the reactive substituent of the silylating agent thus synthesized, there may be mentioned a chlorosilane (Si-Cl) group and the like. Such a reactive substituent has 4 groups capable of bonding to a silicon atom. Of the three substituents, the silylating agent is not necessarily limited to only one and has two or three reactive functional groups, and can also be applied to the chemical modification of the carrier. And, as the reactive functional group of such a silylating agent,
Not limited to chlorosilane to silicon atoms of chlorine (-Cl) are thus allowed to bind, bromine to a silicon atom (-Br), methoxy (-OCH _3), ethoxy (-OCH ₂ CH _3), alkylamino group (-NR Any functional group capable of reacting with an active site such as a hydroxyl group existing on the surface of the carrier such as ₂ ) can be applied to the present invention.

Further, as the method for synthesizing the silylating agent, the method using the addition reaction to the double bond of hydrosilane has been exemplified above, but the method is not limited to this, and, for example, two or more. The silylating agent can also be synthesized by a method of reacting an organic compound having a reactive functional group (mainly chlorine) with an organometallic reagent such as a Grignard reagent.

And the bromination / obtained in this way
The target filler can be obtained by reacting a silylating agent having an iodinated aromatic functional group with a carrier such as silica gel (HO-Si) as shown in the reaction formula (3).

[0044] _{ArX n -O- (CH 2) 3} -Si (CH 3) 2 -Cl + HO-Si ─── → ArX n -O- (CH 2) 3 -Si (CH 3) 2 -O- Si ... (3)

The method 2) using the organometallic compound is the method reported by Locke et al. [DC Locke,
JJ Schermud and B. Banner, Anal. Chem., 44, 90 (1
972)], and in this method, the following reaction formula (4a),
The desired filler is obtained through the two-step reaction process shown in (4b). The reaction represented by the reaction formula (4a) is a reaction of chlorinating a hydroxyl group of a carrier (eg silica gel) using a reagent capable of chlorinating a hydroxyl group such as thionyl chloride. In the reaction represented by the formula (4b), the Grignard reagent is reacted with the chlorinated carrier synthesized in the reaction formula (4a), and the brominated / iodinated aromatic functional group represented by ArX _n is used as the carrier. It is a reaction to combine. In addition, in a reaction formula, Si shows a silica gel residue.

[0046] _{Si-OH + SOCl 2 ─── →} Si-Cl ··· (4a) ArX n MgBr + Si-Cl─── → ArX n -Si ··· (4b)

Further, the method of introducing a reactive functional group of 3) above into a carrier and then binding a brominated / iodinated aromatic functional group to the functional group is the organometallic compound described in 2) above. Is similar to the method of reacting
In this method, as shown in the following reaction formula (5a), a functional group having reactivity such as an amino group is previously introduced into a carrier (eg silica gel), and a functional group capable of reacting with the amino group, for example, a carboxyl group is introduced. The brominated / iodinated aromatic functional group having a group and the carrier into which the reactive functional group obtained in the above reaction formula (5a) is introduced are represented by the following reaction formula (5
As shown in b), the desired filler can be obtained by condensing with a condensing agent such as dicyclohexylcarbodiimide. In addition, in this example, the reaction in which an amide bond is finally formed is shown, but other combinations of functional groups forming an ester bond, an ether bond, or the like can be similarly performed. Moreover, Si-O- in the reaction formula represents a silica gel residue.

NH ₂ (CH ₂ ) ₃ Si (OCH ₃ ) ₃ + HO-Si ─── → NH ₂ (CH ₂ ) ₃ Si (OCH ₃ ) ₂ —O-Si ... (5a) ArX _n COOH + _{NH 2 (CH 2) 3 Si} (OCH 3) 2 -O-Si ─── → ArX n CONH (CH 2) 3 Si (OCH 3) 2 -O-Si ··· (5b)

Furthermore, in the method of producing a filler by substituting bromine or iodine for the aromatic hydrocarbon group bound to the carrier in the above 4), first, as shown in reaction formula (6a), A carrier (eg silica gel)
An aromatic hydrocarbon group is previously bound to. Then
As shown in reaction formula (6b), hydrogen or a substituent on the aromatic ring of the aromatic hydrocarbon group bound to such a carrier is brominated or iodinated to give the desired filler. You can get it. In addition, Si-O- in a reaction formula shows a silica gel residue.

[0050] ArCl + HO-Si─── → Ar- O-Si ··· (6a) Ar-O-Si + nX 2 ─── → ArX n -O-Si ··· (6b)

Thus, the fillers according to the invention can be produced by various synthetic methods, but advantageously various brominated / iodinated aromatic functional groups can be bound to the carrier. Therefore, it is preferable that the silylating agent having a brominated / iodinated aromatic functional group of the above 1) is synthesized by a production method in which a carrier can be easily obtained, because the intended filler can be easily obtained. Become.

The present invention is also characterized in that the fullerene is separated by liquid chromatography using the packing material according to the present invention as described above, whereby the fullerene can be effectively treated. It became possible to separate them. In addition, in the separation operation of such fullerenes by the liquid chromatography method, the same operations and conditions as conventional ones are adopted.

That is, in such a separation operation, fullerenes are supplied as a solution dissolved in a predetermined solvent to the column packed with the packing according to the present invention. By the way, fullerenes are well-dissolved in aromatic hydrocarbon solvents such as trichlorobenzene, toluene, and benzene and carbon disulfide, and are hardly dissolved in aliphatic hydrocarbon solvents such as hexane and isooctane. In the case of purification, it is possible to prepare a higher concentration sample solution for separation by using an aromatic hydrocarbon solvent, preferably carbon disulfide, as a solvent for dissolving fullerenes.

The fullerenes supplied in the form of a solution in this separation column are retained by a packing material,
Subsequently, a mobile phase solvent that is circulated in the separation column,
For example, the fullerene allotrope is sequentially eluted with toluene or a mixed solvent of toluene and hexane, preferably carbon disulfide or a mixed solvent of carbon disulfide and toluene. That is, various allotropes of fullerenes are individually eluted with time from a separation column by a mobile phase solvent, and the eluate discharged from this separation column is separated with time to obtain each allotrope of fullerenes. It is possible to separate them.

Thus, by performing liquid chromatographic separation using the packing material according to the present invention, the allotrope mixture of fullerenes can be separated for each allotrope, and the packing material has a sufficiently large holding power. Therefore, even if a solvent having a large elution power, such as a solvent such as carbon disulfide, is used, the solvent is sufficiently separated, and thus the allotrope can be effectively separated and purified.

[0056]

EXAMPLES In order to clarify the present invention in more detail, some examples of the present invention will be shown below.
It goes without saying that the present invention is not limited by the description of such embodiments. In addition to the following embodiments, the present invention further includes various changes and modifications based on the knowledge of those skilled in the art, in addition to the above specific description, without departing from the spirit of the present invention. It should be understood that improvements and the like can be added.

Example 1 A filler having a stationary phase structure shown in Table 3 below (Examples 1 to 4 of the present invention and Comparative Examples 1 to 3) was used to synthesize (1) an aromatic hydrocarbon compound having a double bond. , (2) Synthesis of silylating agent by addition reaction of chlorosilane to such double bond,
(3) It was synthesized through a three-step reaction of reacting a hydroxyl group on the surface of silica gel as a carrier with chlorosilane. Here, the filler of Comparative Example 3 was a filler to which halogen was not bound, and was synthesized in order to clarify the difference in effect from other filler having a stationary phase to which halogen is bound. . In addition, Conventional Examples 1 to 5 also show existing fillers used for comparison with the filler according to the present invention. In the following, the names of the fillers will be represented by abbreviations.

[0058]

[Table 3]

In addition, in the fillers of Examples 3 and 4 of the present invention and Comparative Example 2, all the halogens bonded to the stationary phase were 1-positioned when the site to which the spacer group was bonded in the aromatic ring was positioned. It is attached to the 2, 4 and 6 positions.

(1) Halogenated phenyl having a double bond
Synthesis of compounds a) 2,3,4,5,6-pentabromobenzylallyl
Synthesis of ether (raw material for PBB) First, 2,3,4,5,6-pentabromotoluene: 1
45.5 g, N-bromosuccinimide: 54.0 g and benzoyl peroxide: 4.89 g were added to carbon tetrachloride: 15
It was made to melt | dissolve in 00 mL and it was made to react by heating at 80 degreeC for 4 hours [reaction formula (7)]. Then, after such reaction, the carbon tetrachloride solution and the generated crystals were separated by filtration, and the carbon tetrachloride solution was washed with water and dried over sodium sulfate, and then the solvent was distilled off under reduced pressure to remove odor. Crude crystals of 2,3,4,5,6-pentabromobenzyl chloride were obtained. On the other hand, the crystals separated from the carbon tetrachloride solution were dissolved in benzene, washed with water, and then dried over sodium sulfate, and then benzene was distilled off under reduced pressure to give 2,2-bromide.
Crude crystals of 3,4,5,6-pentabromobenzyl were obtained. And bromide 2, 3, 4, recovered in this way
The crude crystals of 5,6-pentabromobenzyl were combined and recrystallized to obtain 149 g of crystals.

C ₆ Br ₅ —CH ₃ + Br ₂ ─── → C ₆ Br ₅ —CH ₂ —Br (7)

Then, allyl alcohol: 100 mL
To the above, sodium: 2.74 g (119 mmol) was added to generate an alcoholate at room temperature. After such reaction, the alcoholate produced here is added to the 2,3,4,5,6-pentabromobenzyl bromide obtained in the above reaction:
67.5 g and benzene: 200 mL were added, and the temperature was 50 ° C.
Then, the reaction was carried out for 2 hours [reaction formula (8)]. Then, the remaining allyl alcohol and benzene were distilled off under reduced pressure, and the remaining residue was extracted with chloroform and then washed with a phosphoric acid aqueous solution. Then, this chloroform extracted solution was dried over calcium chloride, chloroform was distilled off under reduced pressure, and hexane was added to recrystallize the resulting solution.
-Pentabromobenzyl allyl ether crystals: 47 g
Got

C ₆ Br ₅ —CH ₂ —Br + HO—CH ₂ —CH═CH ₂ ─── →→ C ₆ Br ₅ —CH ₂ —O—CH ₂ —CH═CH ₂ (8)

B)2,3,4,5,6-pentabromobutane
Synthesis of phenyl allyl ether (Br _FiveRaw material) tert-Butanol: 50 g, 2,3,4,5,6-pepter
Ntabromophenol: Add 12.2 g and heat,
Dissolved. Potassium tert-butoxide in this solution:
2.8g was added to produce salt. Then do not stir
Gall, allyl bromide: 6.0 g, and then at 80 ° C. for 5 hours
The reaction was carried out for a period of time [Reaction formula (9)]. After the reaction, tert-butano
The solvent was distilled off under reduced pressure, water was added, and the mixture was extracted with benzene. Be
The Nazen solution was dried over calcium chloride and then evaporated under reduced pressure.
To give a crude product and recrystallize
Crystals were obtained.

C ₆ Br ₅ —OH + Br—CH ₂ —CH═CH ₂ ─── → C ₆ Br ₅ —O—CH ₂ —CH═CH ₂ (9)

Although not shown specifically, 2,3,4,5,6-pentafluorophenol, 2,4,6-triiodophenol, 2,4,4
Using 6-tribromophenol, 2,4,6-trichlorophenol, and phenol, respectively,
Raw materials for the respective fillers of F ₅ , I ₃ , Br ₃ , Cl ₃ , and POP were synthesized.

(2) Reaction of addition of chlorosilane to double bond
Synthesis of silylating agents by reaction 2,3,4,5,6-pentabromobenzyloxypro
Synthesis of Pyrdimethylchlorosilane A silylating agent is synthesized by adding chlorosilane to the raw material of each of the fillers obtained above. Here, as an example, 2,3,4,5,6-pentabromo is used. The synthesis of benzyloxypropyldimethylchlorosilane will be shown.

First, 2,3,4,5,6-pentabromobenzyl allyl ether: 137.3 g (253 mmo)
l) was dissolved in benzene: 500 mL, chloroplatinic acid: 50 mg and dimethylchlorosilane: 40 mL were added, and the mixture was refluxed at 80 ° C. for 3 hours [reaction formula (10)]. After the reaction, the platinum catalyst was removed by filtration and the solvent was distilled off under reduced pressure to obtain 2,3,4,5,6-pentabromobenzyloxypropyldimethylchlorosilane.
Other fillers were synthesized in the same manner.

C ₆ Br ₅ —CH ₂ —O—CH ₂ —CH═CH ₂ + H—Si (CH ₃ ) ₂ —Cl Pt ─── → C ₆ Br ₅ —CH ₂ —O— (CH ₂ ) _{3 -Si (CH 3) 2 -Cl ···} (10)

(3) Reaction of Silylating Agent with Silica Gel Next, various silylating agents obtained as described above are
Each target filler was synthesized by reacting with a hydroxyl group (HO-Si) of silica gel as a carrier. Here, as one specific example thereof, a synthesis example of a 2,3,4,5,6-pentabromobenzyloxypropylsilylated filler will be shown.

First, 1 part by weight of silica gel (particle size: 5 μm, pore size: 10 nm, surface area: 300 m ² / g) was dispersed in 30 parts by weight of toluene, and 2, 3, 4, 5, were added thereto.
6-Pentabromobenzyloxypropyldimethylchlorosilane (2 parts) and pyridine (0.5 parts) were added, and the mixture was heated under reflux for 8 hours [reaction formula (11)]. After this reaction, 100 parts by weight of each of methanol and chloroform were sequentially suction-filtered and washed, and the filler was dried at 50 ° C.

C ₆ Br ₅ —CH ₂ —O— (CH ₂ ) ₃ —Si (CH ₃ ) ₂ —Cl + HO—Si ─── → C ₆ Br ₅ —CH ₂ —O— (CH ₂ ) ₃ —Si _{(CH 3) 2 -O-Si} ··· (11)

As described above, the elemental analysis values of the fillers respectively synthesized and the amount of the stationary phase bound to the surface of the silica gel as the carrier were measured, and the results were
It is shown in Table 4 below. The halogen content of the filler represented by X% is about I ₃ , iodine, PBB, Br ₅ ,
The content of bromine is shown for Br ₃ , chlorine is shown for Cl ₃ , and fluorine is shown for F ₅ . Further, silica gel used in this example had a surface area of 1g per 300 meters ^2, the value indicated by the amount of stationary phase bound to the surface area of 1 m ² per ([mu] mol) is a surface reaction rate. The filler having a high surface reaction rate shows that the stationary phase is bound to the surface of the silica gel at a high rate. The surface reaction rate was calculated from the content rate of halogen in the case of the halogen-bonding type filler, and was calculated from the content rate of carbon in the case of the non-halogen-bonding type filler.

[0074]

Example 2 Each of the fillers synthesized in Example 1 had an inner diameter of 4.
It was packed in a 6 mmφ × 150 mm long chromatographic tube and the retention property of the packing material against fullerenes was evaluated.
Specifically, the liquid chromatography apparatus includes a liquid feed pump (LC-9A type: manufactured by Shimadzu Corporation), a column packed with each of the packing materials, and a loop injection valve for injecting a sample (Rheodyne And an ultraviolet absorption detector (SPD-6A type UV detector: Shimadzu Corporation)
The flow rate of the mobile phase solvent was set to 1.0 mL / min in all cases. Further, the detection sensitivity of the ultraviolet absorption detector was set to 0.16 AUFS, and the measurement was performed. The column temperature was adjusted with a constant temperature water bath so that the analysis temperature was 30 ° C. Then, the data processing device (CR-
5A type: manufactured by Shimadzu Corporation) was used.

A sample used for evaluating the retention characteristics of fullerenes by the filler was obtained by separating and purifying fullerene mixed powder (Refined C ₆₀ / C ₇₀ : manufactured by Vacuum Metallurgical Co., Ltd.). Fullerenes were used. The fullerene mixed powder is obtained by extracting a fullerene allotrope from soot containing fullerenes and then drying it, and contains C ₆₀ , C ₇₀ and a small amount of higher fullerenes. More specifically, C ₆₀ , C ₇₀ , C ₇₆ , C ₈₄ , and C ₉₀ are separated and purified from the fullerene mixed powder to obtain a standard product, and the fullerene standard product is measured for purity by the above high performance liquid chromatography. It was confirmed that the purity was 95% or more by using a graphic apparatus. Further, the identification was performed using a mass spectrometer, and the standard fullerene was diluted with toluene to a concentration of about 0.3 to 1 mg / mL to prepare a standard sample solution. Then, the standard sample solution thus prepared was injected with a predetermined amount (1 μL to 5 μL) using a microsyringe, and the retention property of fullerenes by the filler was measured, and the results are shown in Table 5 below. It was shown to.

That is, Table 5 shows the holding power (k 'value) of the fullerene given by each filler, and the k'value is divided by the surface reaction rate in parentheses,
Unit surface reaction rate (μmol / m) of the stationary phase to the filler
² ) The holding power per hit is shown. Moreover, what is described as k'value (toluene) shows the retention property when toluene is used as the mobile phase solvent, and what is described as k'value (25% toluene / 75% hexane) is the capacity. 2 by ratio
The retention characteristic of fullerene when a hexane solution containing 5% toluene is used as a mobile phase solvent is shown.

The holding power per unit surface reaction rate is shown here in order to properly evaluate the holding power given by each stationary phase. That is, it is generally considered that the retention of solute by the packing material is expressed as the sum of the interactions with the solute by all the stationary phases bound to the packing material. In order to justify the size, the interactions should be compared by the same number of stationary phases. Therefore, the coercive force (k 'value) per unit surface reaction rate (μmol / m ² ) is also shown, and the comparison is made by this. Also, when toluene is used as the mobile phase solvent, some of the fillers have very small retention (F ₅ and POP), which makes it difficult to make an accurate comparison. Hexane having a small elution output was used as a mobile phase solvent in which a mixed solvent containing 75% by volume was added as a mobile phase solvent, and the holding power in a state where the holding power was increased was measured and compared.

[0079] Flow rate: 1.0 mL / min; Detection wavelength: 285 nm

Examining such results, a filler composed of a carrier chemically modified with an aromatic functional group having three or more bromine and / or iodine bonded thereto has an excellent holding power. It is understood that they have.
That is, a filler chemically modified with an aromatic functional group to which bromine or iodine is bound, such as PBB, Br ₅ , I ₃ , Br ₃ or the like, is a filler such as Cl ₃ , F ₅ , POP or the like. Retention of several times to several tens of times compared to a filler that is chemically modified with an aromatic substituent having chlorine or fluorine bonded instead of iodine or an aromatic substituent having nothing bonded It has a force (k 'value). Also,
It was confirmed that Br ₅ has a larger coercive force than Br _{3, and the} larger the number of bromine or iodine bonded to the aromatic functional group, the larger the coercive force.

Further, in the comparison of Br ₅ , Br ₃ and POP using the substituents having the same basic skeleton as the stationary phase, 3
The Br ₃ having one bromine bonded thereto had a large coercive force about 7 to 10 times that of the POP to which no halogen was bonded. On the other hand, Br ₅ having five bromine bonds is Br ₃
Since it gives a holding force about 3 to 4 times larger than that, when considering each magnification, such Br ₅ is P
It is estimated to have a holding power of about 20 to 40 times that of OP.

Further, in Table 5, POP and F ₅
When compared with the results, F ₅ has a smaller retention per unit surface reaction rate than that of POP, which is about 1/15 to 1/7, and the modification of the stationary phase with fluorine has a retention force for fullerene. Is understood to decrease. Also, Cl ₃ chlorine is allowed three bonds is about the POP 2
While it had only double the holding power, I ₃ to which ₃ iodines were bound had a fullerene holding power 10 to 12 times or more that of POP.

On the other hand, as an influence of the spacer, PBB and B
Comparing with r ₅ , PBB showed a holding force 1.4 to 1.7 times as high as the holding force of Br ₅ , but compared to the difference with the holding force of POP, about the same degree. Therefore, it is considered that the difference in holding force due to the difference in spacer can be ignored. However, since the spacers shown here are not optimal, it is possible that some improvement in holding power may be achieved by varying the spacers.

From the above results, the filler chemically modified with the aromatic functional group substituted with bromine and / or iodine is compared with the filler chemically modified with the unsubstituted aromatic functional group, It became clear that it has a strong holding power for fullerenes. Further, it was confirmed that the retention force of the filler chemically modified with an aromatic substituent substituted with chlorine is slightly stronger, but it is still difficult to say that the retention force is still sufficient. It was revealed that the retention force is rather weak in the filler chemically modified with the substituted aromatic substituent. Therefore, in order for the filler to provide sufficient retention for fullerenes and the like, it is necessary that bromine and iodine are bound to the aromatic functional group that chemically modifies the carrier that constitutes such filler. .

Example 3 In order to show that the filler according to the present invention can effectively separate fullerenes, it was confirmed that the existing filler and the filler according to the present invention were used. A comparison was made regarding the retention of fullerenes and the separation coefficient, and the results are shown in Table 6 below. Here, PBB was representatively selected as the filler according to the present invention. Also,
Only when C18 was used as a filler, hexane was used as the mobile phase solvent in order to ensure proper retention.

[0086] Mobile phase solvent: Toluene (C18 mobile phase solvent: hexane) Detection wavelength: UV 285 nm Flow rate: 1.0 mL / min Column size: Inner diameter 4.6 mm φ × length 150 mm

The separation coefficient shown here is the ratio of the holding forces (k 'values) given by the two peaks of C ₆₀ and C ₇₀ , that is, the holding force for C ₆₀ divided by the holding force for C ₇₀ . And is one of the measures showing the degree of separation between peaks. The fact that this separation coefficient is large means that C
_This means that the time from the elution of ₆₀ to the elution of C ₇₀ becomes long, and it means that C ₆₀ and C ₇₀ are well separated from each other.

Further, in this case, the mobile phase solvent is
Toluene is used, but when comparing PYP and PBB, which show a strong holding power even for toluene having a large leaching power, the holding power for C ₆₀ is a little smaller than that of PBB, whereas that of C _{70 is} The holding power for PBB is a little larger than that for PBB. That is, it is understood that the separation coefficient of PBB is larger than that of PYP, and fullerenes can be separated more advantageously. Then, regarding this separation coefficient, PB
B shows the largest value among the fillers shown in Tables 5 and 6 above, and it was shown that it has excellent performance for separation of fullerenes.

Example 4 Next, with respect to PYP and PBB which showed a large holding power even when toluene was used as a mobile phase solvent, a mixed mobile phase solvent of carbon disulfide and toluene showing a higher solubility than toluene. A comparison of retention was made and the results are shown in Table 7 below.

[0090] Column size: Inner diameter 4.6 mmφ × Length 150 mm; Detection wavelength: 285-385 nm

From the results shown in Table 7, PBB,
For both PYP fillers, it was confirmed that the retention of fullerenes decreased as the proportion of carbon disulfide contained in the mobile phase solvent increased, but PBB has a retention capacity higher than that of PYP. The decrease was small. For that, 100
% Even when using carbon disulfide as a mobile phase solvent, P
It was shown that BB had a retention force three times that of PYP and sufficient retention force to completely separate C ₆₀ and C ₇₀ . On the other hand, PYP is 100% carbon disulfide,
It gave very little retention for C ₆₀ and C ₇₀ . That is, it has been revealed that the filler according to the present invention has a very strong retention force capable of separating fullerenes even in carbon disulfide, which has higher solubility than toluene.

Further, the lower limit of the amount of the stationary phase (brominated / iodinated aromatic functional group) bonded to the filler is P when the 100% carbon disulfide is used as the mobile phase solvent.
Comparing the holding powers of BB and PYP for fullerenes, PBB shows a holding power about three times that of PYP. From this, assuming that the coercive force and the reaction rate of the stationary phase (brominated / iodinated aromatic functional group) to the carrier are correlated, the reaction rate of the stationary phase to the carrier in PBB is 1/3, That is, 0.6 μmol / m ² or more,
The bromine content is 6% or more, and it is considered that it has a holding power equal to or more than PYP, but in order to sufficiently separate the fullerenes even when carbon disulfide is used as the mobile phase solvent, it is 1/2 or more. It is desirable to have a reaction rate of.

Example 5 Carbon disulfide was used as the mobile phase solvent, and PB was used as the filler.
B was used to separate a mixture of higher fullerenes (a generic name for fullerenes having more carbon atoms than C ₇₀ ). The separation conditions at this time are as follows: column: inner diameter 4.6 mmφ ×
Length 150 mm, mobile phase solvent flow rate: 1.0 mL / mi
n, column temperature: 30 ° C., detection wavelength: UV385 nm. And the result is shown in FIG.

As is clear from FIG. 1, carbon disulfide
Is used as a mobile phase solvent, C₆₀And C₇₀And is almost perfect
Separated into C₇₆, C₈₄, C₉₀About 3 minutes
It is easily understood that they are separated by. By the way, two
Separation of higher fullerenes using carbon sulfide as a mobile phase solvent
In addition, Kikuchi et al. ₆₀
・ The science of fullerenes ", P. 58), but 100
It takes 0 minutes or more and it is extremely long.
While using the PBB according to the present invention for the separation time,
Is the resolution less than that of the chromatographic separation method?
It was. Thus, using the filler according to the invention
By doing so, the separation ability of fullerenes can be dramatically improved.
You can get it.

Example 6 In the above examples, the separation of fullerenes was mainly described, but the filler according to the present invention is not only used for the separation of fullerenes, but also for the separation of various other substances. It can be applied. Even in such a case, excellent separation ability can be exhibited as in the case of separating fullerenes. Specifically, in a liquid chromatographic separation using a packing material according to the invention,
Besides the example of separation of fullerenes, an example of separation of xylene isomers will be shown. It is known that, among such xylene isomers, it is usually difficult to separate the meta isomer and the para isomer, and it is known that they can hardly be separated by liquid chromatography using C18 which is a general packing material. .

First, when 70% by volume aqueous methanol solution was used as the mobile phase solvent and when C18 was used as the filler, the separation coefficient for the meta isomer and para isomer of xylene was 1.01, and further migration was carried out. Even if the solvent content is reduced by reducing the methanol content of the phase solvent to 60%,
The separation factor was 1.02, and almost no separation was possible. The separation coefficient here is represented by the k ′ value of the meta isomer / the k ′ value of the para isomer. In addition, even when using a filler such as NPE or PYE which has been conventionally used, the separation coefficient is about 1.02 to 1.03, and even if these fillers are used, the separation of xylene isomers is extremely difficult. It was very difficult.

On the other hand, when such a xylene isomer mixture was separated by liquid chromatography using PBB as a packing material, the separation coefficient of those isomers was 1.05, and when another packing material was used. A chromatogram was obtained in which a sample that eluted as a single peak could be easily recognized as a sample composed of multiple components.

[0098] Column size: Inner diameter 4.6 mmφ x length 150 mm

[0099]

As is apparent from the above description, in the filler according to the present invention, the carrier constituting the filler is
Since it has been chemically modified with an aromatic functional group formed by binding three or more bromine and / or iodine, it can exhibit a strong retention force for solutes, and thus, it is sufficiently retained by conventional fillers. Alternatively, it can be advantageously applied to substances such as fullerenes which could not be separated, and can be effectively retained and separated in a liquid chromatography operation.

In producing such a packing material for liquid chromatography according to the present invention, bromine and / or
Alternatively, a silylating agent having an aromatic functional group having 3 or more iodines bonded thereto is used to react with a hydroxyl group on the surface of the carrier, and thus an aromatic functional group having bromine and / or iodine bonded thereto. Thus, the stationary phase having is advantageously formed on the surface of the carrier constituting the filler, and the filler having the target structure can be easily obtained.

Furthermore, when the above-mentioned packing material is used in the liquid chromatographic separation of fullerenes, it can be effectively separated, and therefore it is suitable for separating a large amount of fullerenes at the same time. Since such a filler has a strong holding power, it is possible to advantageously employ carbon disulfide as a mobile phase solvent, so that fullerenes can be separated more efficiently. is there.

[Brief description of drawings]

FIG. 1 is a chromatogram showing an example of the result of separating a fullerene mixture by liquid chromatography using the packing material according to the present invention.

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01N 30/48 B01D 15/08 G01N 30/88

Claims (7)

(57) [Claims] 1. A filler comprising a carrier chemically modified with an aromatic functional group in which a total of three or more bromine and / or iodine are bonded to an aromatic ring, and the carrier is used.
Is a silica gel, a packing material for liquid chromatography. 2. A total of bromine and / or iodine in the aromatic ring
Chemical modification with aromatic functional groups formed by combining three or more
In the fillers are formed of a decorated by carrier, said aromatic group is, through an oxy alkyl silyl group, packing material for liquid chromatography, characterized by being allowed to chemically bond to the carrier. Wherein the carrier is, Ru silica gel der 請 Motomeko 2
The packing material for liquid chromatography according to item 1. 4. A silylating agent having an aromatic functional group having a total of three or more bromine and / or iodine bonded to an aromatic ring is used, and the silylating agent is reacted with a hydroxyl group on the surface of a carrier. A method for producing a packing material for liquid chromatography, characterized in that the stationary phase having the aromatic functional group is formed on the surface of the carrier. 5. The carrier according to claim 4, which is silica gel.
The method for producing a packing material for liquid chromatography as described in 1. 6. A method of separating fullerenes by a liquid chromatography method, which comprises a carrier chemically modified with an aromatic functional group having a total of three or more bromine and / or iodine bonded to an aromatic ring. A method for separating fullerenes, which comprises using a filler. 7. The method for separating fullerenes according to claim 6, wherein carbon disulfide is used as a mobile phase solvent.