JP2020132489A - Production method of carbon material, carbon material, and carbon material composition - Google Patents

Abstract

To provide a novel carbon material: having a structure similar to graphene from the viewpoint of crystal structure; while having a structure nearly identical to reduction type graphene oxide in terms of being a nearly monolayer oxygen-containing carbon material, being different from reduction type graphene oxide in terms of practically containing no element other than carbon and oxygen and also being different from graphite from the viewpoint of crystal structure; having a very low ratio of the content of contaminants such as nitrogen, sulfur, phosphorus and a metal other than an alkali metal; and being able to exist also in a shape different from a film (typically in a bulk state), further, to provide a novel carbon material composition including such a novel carbon material, and to provide a production method of such a novel carbon material.SOLUTION: In a production method of a carbon material of the invention, an aromatic ring-containing compound (A) with molecular weight of 500 or less and constituted of carbon, hydrogen, and oxygen is calcined at a temperature of 700°C or more.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing a carbon material, a carbon material, and a carbon material composition.

In recent years, carbon materials such as carbon nanotubes, fullerene, graphite, graphene, graphene oxide, reduced graphene oxide, artificial graphite, and carbon black have been made into new functional materials in various fields due to their characteristic physical properties. (For example, Non-Patent Documents 1-3).

Graphene is a two-dimensional sheet-like carbon material, and has a structure in which a six-membered ring made of sp2 carbon is spread. Graphite usually refers to a graphene having a laminated structure of two or more layers in which two-dimensional sheet-shaped graphenes are bonded to each other by van der Waals force, but one layer of graphite may be referred to as graphene.

The existence of graphene has been known for a long time, but until recently, a method for extracting a single graphene from graphite has not been established. In 2004, it was discovered that graphene flakes could be taken out by peeling the surface of highly oriented anhydrous graphite with adhesive tape and sticking the peeled material on the substrate, and then mass production and low Aiming at cost production, graphene production method by vapor phase film formation method such as CVD (chemical vapor deposition film formation method) and graphene (reduced graphene oxide: RGO) production by reduction method of graphene oxide (GO) The method is being considered.

However, the method for producing graphene by a vapor phase film forming method such as CVD (chemical vapor deposition film forming method) has a problem that it cannot be obtained as a shape other than a film (typically, a bulk shape), and a flammable gas. There is a problem that the metal must be used, and there is a problem that the metal is contained as an impurity because the film is formed on a metal substrate having catalytic performance such as Cu.

On the other hand, a method for producing graphene (reduced graphene oxide: RGO) by a reduction method for graphene oxide (GO) has been studied in recent years as a production method having the potential to solve the above problems.

Reduced graphene oxide (RGO) can typically be produced by producing graphene oxide by oxidizing graphite and reducing the resulting graphene oxide. However, in this production method, nitrogen, sulfur, phosphorus, and metals other than alkali metals derived from oxidizing agents, reducing agents, and catalysts are mixed as impurities, and the total content ratio of carbon and oxygen in all elements decreases. Therefore, there is a problem that it is difficult to obtain a high-purity reduced graphene oxide.

A method for easily producing a graphite film without using a flammable gas has recently been reported (Patent Document 1). However, this graphite film also has a problem that it cannot be obtained as a shape other than the film (typically, a bulk shape).

JP-A-2017-132648

Nature, 354, p. 56-58 (1991) Science, 306, p. 666-669 (2004) Riichiro Saito, "State-of-the-art Graphene Technology and Widespread Applications," Chapter 2. Basic physical properties of graphene, 3. Photoelectron properties of graphene

The applicant has made diligent studies to develop a new carbon material that can solve the above-mentioned conventional problems. Specifically, it has the same or similar crystal structure as graphene, and has almost the same structure as reduced graphene in that it is an oxygen-containing carbon material having almost a single layer, however, carbon and carbon and It is a novel carbon material that is different from reduced graphene in that it contains substantially no elements other than oxygen, and is also different from graphite in terms of crystal structure, and is a carbon that can solve the above-mentioned conventional problems. Research was conducted on materials and methods for producing such carbon materials.

That is, the subject of the present invention is that the crystal structure has the same or similar structure as graphene, and although it has almost the same structure as reduced graphene in that it is an oxygen-containing carbon material having almost a single layer, carbon. Unlike reduced graphene oxide in that it contains virtually no elements other than oxygen, it is different from graphite in terms of crystal structure, and contains impurities such as nitrogen, sulfur, phosphorus, and metals other than alkali metals. It is an object of the present invention to provide a novel carbon material having a very low proportion and which can exist in a shape other than a film (typically, in a bulk state). Furthermore, it is an object of the present invention to provide a novel carbon material composition containing such a novel carbon material. Another object of the present invention is to provide a method for producing such a novel carbon material.

The method for producing a carbon material of the present invention is
An aromatic ring-containing compound (A) having a molecular weight of 500 or less, which is composed of carbon, hydrogen, and oxygen, is calcined at a temperature of 700 ° C. or higher.

In one embodiment, the condensation reaction temperature of the aromatic ring-containing compound (A) is 400 ° C. or lower.

In one embodiment, the initial temperature of the aromatic ring-containing compound (A) at a temperature of 50 ° C. when TG-DTA analysis is performed under a nitrogen gas atmosphere under a temperature rising condition of 40 ° C. to 10 ° C./min. The weight ratio (M500 / M50) of the weight M500 at a temperature of 500 ° C. to the weight M50 is 0.2 or more.

In one embodiment, the aromatic ring-containing compound (A) is an aromatic compound having a hydroxyl group.

In one embodiment, the firing temperature is 1000 ° C to 1500 ° C.

In one embodiment, in the method for producing a carbon material of the present invention, it can be produced in a bulk state.

The carbon material of the present invention is
Raman analysis shows G band, D band, G'band,
XRD analysis showed no graphite-derived peaks
XPS analysis showed that the total content of carbon and oxygen in all elements was 99.9% or higher.
According to XRF analysis, the proportions of the contents of metals other than nitrogen, sulfur, phosphorus, and alkali metals are 100 ppm or less, respectively.

In one embodiment, the carbon material of the present invention exhibits a D + D'band and / or a 2D'band by Raman analysis.

In one embodiment, the carbon material of the present invention may exist in bulk.

The carbon material composition of the present invention contains the above carbon material.

In one embodiment, the carbon material composition of the present invention comprises a solvent.

In one embodiment, the carbon material is dispersed in the solvent.

In one embodiment, the carbon material composition of the present invention comprises a resin.

In one embodiment, the carbon material is dispersed in the resin.

According to the present invention, the crystal structure is the same as or similar to that of graphene, and the structure is almost the same as that of reduced graphene in that it is an oxygen-containing carbon material having almost a single layer, but carbon and oxygen. Unlike reduced graphene oxide in that it does not substantially contain elements other than graphite, it is different from graphite in terms of crystal structure, and the content ratio of impurities such as nitrogen, sulfur, phosphorus, and metals other than alkali metals is high. It is possible to provide a novel carbon material which is very low and can exist in a shape other than a film (typically, in a bulk state). Furthermore, it is possible to provide a novel carbon material composition containing such a novel carbon material. It is also possible to provide a method for producing such a novel carbon material.

It is a Raman analysis result of the carbon material obtained in Example 1. It is an XRD analysis result of the carbon material obtained in Example 1. It is a Raman analysis result of the carbon material obtained in Comparative Example 1. It is an XRD analysis result of the carbon material obtained in Comparative Example 1. It is an XRD analysis result of the carbon material obtained in Comparative Example 2.

≪Manufacturing method of carbon material≫
In the method for producing a carbon material of the present invention, an aromatic ring-containing compound (A) having a molecular weight of 500 or less, which is composed of carbon, hydrogen, and oxygen, is calcined at a temperature of 700 ° C. or higher.

The method for producing a carbon material of the present invention is a method for producing a "specific aromatic ring-containing compound" at a "specific temperature" by "firing instead of forming a film".

The firing temperature is preferably 700 ° C. to 2000 ° C., more preferably 800 ° C. to 1800 ° C., further preferably 900 ° C. to 1600 ° C., and particularly preferably 1000 ° C. to 1500 ° C. When the firing temperature is within the above range, the total content of carbon and oxygen in all elements is very high, and the content of impurities such as nitrogen, sulfur, phosphorus, and metals other than alkali metals is high. It is possible to produce novel carbon materials that are very low and can also exist in shapes other than membranes (typically bulk).

In the production method of the present invention, it can be preferably produced in a bulk state. Specifically, in the production method of the present invention, the aromatic ring-containing compound (A) is preferably heated in a bulk state. In general, the properties of bulk are the inherent properties of the substance. That is, a substance in a bulk state can determine the basic properties of the substance, for example, values such as boiling point, melting point, viscosity, and density. The physical properties of a substance refer to the properties of the bulk part. Examples of the bulk state are particles, pellets, films and the like. Examples of the state of existence of particles include powder. The film is preferably a self-supporting film. Heating the aromatic ring-containing compound (A) in a bulk means, for example, heating particles (powder) made of the aromatic ring-containing compound (A), particles made of the aromatic ring-containing compound (A) (for example, powder). ) Is molded into pellets or films by compression molding or the like, and then the molded body is heated, particles (for example, powder) composed of the aromatic ring-containing compound (A) are heated in a liquid, and the like. Including acts. When heating particles (for example, powder) or a molded product, for example, they may be placed in a container and heated. As the container, any suitable container may be adopted. As such a container, for example, a container made of a material that does not substantially deteriorate at a heating temperature is preferable. Further, it is preferable that the surface with which the particles (for example, powder) or the molded product comes into contact is made of a material that does not chemically react with the aromatic ring-containing compound (A) when heated. By heating the particles (for example, powder) or the molded product under preferable conditions, a carbon material can be obtained, and in the heating step, the aromatic ring-containing compound (A) near the melting point of the aromatic ring-containing compound (A). A) may melt and become liquid. Even after such a process, it is included in "heating the aromatic ring-containing compound (A) in a bulk state". On the other hand, as an example of what is not meant to be "heated in a bulk state" in the present invention, for example, the aromatic ring-containing compound (A) is dissolved in a solvent and applied to an arbitrary substrate to form a film. Examples thereof include a method of forming a thin film by heating together with a substrate, a chemical vapor deposition method (CVD) method, a physical vapor deposition method (PVD), and a thin film vapor deposition heating method. As a thin film, it generally means a range in which the film thickness is 1 μm or less.

As a heating method, a tubular furnace, a firing furnace such as a box furnace, a heating reaction device using a heat medium, a heating reaction device using microwaves, or the like can be used. The heating conditions can be under vacuum, normal pressure, pressure, or the like. As the condition of the heating atmosphere, it can be performed in the atmosphere, the atmosphere of the inert gas, or the like. The heating atmosphere is preferably an atmosphere of an inert gas such as nitrogen or argon.

As the heating time, any appropriate heating time can be adopted depending on the molecular weight required for the carbon material to be produced, solubility, dispersibility, and the like. Such heating time is, for example, preferably 1 minute to 48 hours, more preferably 15 minutes to 24 hours, further preferably 30 minutes to 12 hours, and particularly preferably 1 hour to 10 hours. Is.

The aromatic ring-containing compound (A) is an aromatic ring-containing compound having a molecular weight of 500 or less and composed of carbon, hydrogen, and oxygen.

The aromatic ring-containing compound (A) may be one kind of compound or a mixture of two or more kinds of compounds. When the aromatic ring-containing compound (A) is a mixture of two or more kinds of compounds, it is sufficient that at least one or more kinds of compounds in the mixture have the physical properties, structure, etc. described in the present invention, and the compound is used as a reference. Then, various conditions such as heating temperature and heating time may be determined.

The aromatic ring-containing compound (A) is composed of carbon, hydrogen, and oxygen. The term "composed of carbon, hydrogen, and oxygen" as used herein means that the elements constituting the molecular structure itself of the aromatic ring-containing compound (A) are carbon, hydrogen, and oxygen.

The molecular weight of the aromatic ring-containing compound (A) is 500 or less, preferably 50 to 500, more preferably 75 to 450, still more preferably 80 to 400, and particularly preferably 100 to 350. When the molecular weight of the aromatic ring-containing compound (A) is within the above range, the total content of carbon and oxygen in all the elements is very high, and impurities such as nitrogen, sulfur, phosphorus, and metals other than alkali metals are contained. It is possible to produce a novel carbon material having a very low content ratio and which may exist in a shape other than the film (typically, in bulk). Further, if the molecular weight of the aromatic ring-containing compound (A) is within the above range, it can move freely in the carbonization process because it is a small molecule, and the reactivity can be high, so that it is carbonized from a low temperature. There are merits and process merits such as less organic gas as a by-product in the carbonization process.

The aromatic ring-containing compound (A) is preferably a solid in an environment of 23 ° C. and has a melting point. By having a melting point, it melts in the process of firing, and the reaction between molecules proceeds well. If it does not have a melting point, it does not melt in the process of firing, so that the positions of the molecules are fixed, the reaction between the molecules is difficult to promote, and it is difficult to make a carbon material. By adopting such an aromatic ring-containing compound (A), the reaction can be promoted. In addition, the solubility of the obtained carbon material in a solvent can be improved (for example, more components of the carbon material can be dissolved in the solvent, and more types of solvents can be dissolved in the carbon material).

The aromatic ring-containing compound (A) typically undergoes a condensation reaction between the same molecule and / or between different molecules by heating.

The aromatic ring-containing compound (A) preferably has an aromatic structure in a skeleton that does not contribute to condensation. By having the skeleton aromatic, the carbon component of the resulting carbon material can be more stable. As such an aromatic structure, for example, an aromatic structure composed of carbon atoms such as benzene, naphthalene, anthracene, phenanthrene, and triphenylene is preferable.

As the aromatic ring-containing compound (A), an aromatic compound having a hydroxyl group is particularly preferable. By adopting an aromatic compound having a hydroxyl group as the aromatic ring-containing compound (A), the total content ratio of carbon and oxygen in all elements is much higher, and metals other than nitrogen, sulfur, phosphorus, and alkali metals are obtained. It is possible to produce a novel carbon material having a much lower content ratio of impurities such as, and which may exist in a shape other than a film (typically, a bulk shape).

As the aromatic ring-containing compound (A), an aromatic ring-containing compound having a highly symmetric structure is particularly preferable. By adopting an aromatic ring-containing compound having a highly symmetric structure as the aromatic ring-containing compound (A), the total content of carbon and oxygen in all the elements is much higher, and nitrogen, sulfur, phosphorus and alkali are further increased. It is possible to produce a novel carbon material in which the content ratio of impurities such as metals other than metal is much lower and can exist in a shape other than a film (typically, a bulk shape).

As the condensation reaction temperature of the aromatic ring-containing compound (A), any appropriate condensation reaction temperature can be adopted as long as the effects of the present invention are not impaired. The condensation reaction temperature is preferably 400 ° C. or lower, more preferably 200 ° C. to 370 ° C., and most preferably 250 ° C. to 350 ° C. in that the effects of the present invention can be more exhibited. .. By starting carbonization at such a low temperature, decomposition side reactions that are thought to occur at a higher temperature can be suppressed.

The weight of the aromatic ring-containing compound (A) at a temperature of 500 ° C. with respect to the initial weight M50 at a temperature of 50 ° C. when TG-DTA analysis was performed under a nitrogen gas atmosphere under a heating condition of 10 ° C./min. The weight ratio of M500 (M500 / M50) is preferably 0.2 or more, more preferably 0.2 to 0.9, and most preferably 0., in that the effects of the present invention can be more exhibited. It is 3 to 0.8. By using the aromatic ring-containing compound (A) in which the above weight ratio (M500 / M50) falls within the above range, the effect of the present invention can be further exhibited.

<Representative Embodiment of Aromatic Ring-Containing Compound (A) (Embodiment 1)>
A typical embodiment (Embodiment 1) of the aromatic ring-containing compound (A) is an aromatic ring-containing compound that decomposes by heating to generate radicals on the aromatic ring. Aromatic ring-containing compounds in which radicals are generated on the aromatic ring can undergo a condensation reaction between the same molecule and / or between different molecules to become a carbon material.

The aromatic ring-containing compound that decomposes by heating and generates radicals on the aromatic ring is preferably an aromatic ring-containing compound that generates a gas (a gas that is in a gaseous state at normal temperature and pressure) by heating.

As the aromatic ring-containing compound that generates a gas by heating, any suitable aromatic compound can be adopted as long as it is an aromatic ring-containing compound and a gas is generated by heating. The gas that is in a gaseous state at such normal temperature and pressure is preferably at least one selected from CO, CO ₂ , O ₂ , and H ₂ .

Aromatic compounds that generate CO and / or CO ₂ by heating include, for example, aromatic compounds having a "-C (= O)-" and / or "-OC (= O)-" structure (for example, , Aromatic ketone derivatives, aromatic ester derivatives, acid anhydrides, etc.) and the like.

Examples of aromatic compounds that generate CO and / or CO ₂ by heating include the following compounds.

Examples of aromatic compounds that generate O ₂ by heating include aromatic compounds having an “—O—O—” structure (for example, aromatic carbon oxides, aromatic peroxides, etc.).

Examples of aromatic compounds that generate O ₂ by heating include the following compounds. In the following compounds, R represents a hydrogen atom or an alkyl group, an aryl group, or a heteroaryl group which may have a substituent.

Examples of the aromatic compound that generates H ₂ by heating include a condensed polycyclic aromatic compound having a “−CH _2- ” structure (for example, a phenalene compound).

Examples of aromatic compounds that generate H ₂ by heating include the following compounds.

Aromatic ring-containing compounds that decompose by heating to generate radicals on the aromatic ring have degradability by heating, and gas molecules (preferably CO, CO ₂ , etc.) are decomposed by separating and decomposing at least a part of the skeleton. It is an aromatic ring-containing compound in which at least one selected from O ₂ and H ₂ ) is produced and radicals are generated on the remaining aromatic ring. By using such an aromatic ring-containing compound, the reaction occurs only by its own decomposition without the need for a reaction catalyst, so that the by-products of the chemical reaction and the reaction catalyst are present in the carbon material, which is fatal. It is possible to suppress the formation of specific impurities and obtain a higher quality carbon material. Further, by using such an aromatic ring-containing compound, a carbon material can be obtained without using a flammable gas. Further, such an aromatic ring-containing compound may have high reactivity that does not require catalytic action.

<Representative Embodiment of Aromatic Ring-Containing Compound (A) (Embodiment 2)>
A typical embodiment of the aromatic ring-containing compound (A) (Embodiment 2) is a compound in which one neutral molecule is formed and desorbed from two or more kinds of groups by a condensation reaction. In the second embodiment, one compound may have two or more kinds of groups, or the groups of each of the two or more compounds may be combined to form two or more kinds of groups. It may be. Such an aromatic ring-containing compound (A) can cause a condensation reaction between the same molecule and / or between different molecules to become a carbon material.

As the condensation reaction, if it is a condensation reaction in which one neutral molecule is formed and desorbed from two or more kinds of groups, any appropriate condensation reaction is adopted as long as the effect of the present invention is not impaired. obtain. By performing such a condensation reaction, it may be possible to carry out the reaction at a relatively low temperature. Such a condensation reaction includes, for example,
(A) Condensation reaction due to the formation and elimination of H ₂ O from the -H group and the -OH group.
(B) A condensation reaction in which ROH is formed and eliminated from an -H group and a -OR group (R is an arbitrarily substituted or unsubstituted alkyl group).
(C) Condensation reaction due to the formation and elimination of RCOOH from the -H group and the -OOCR group (R is any suitable substituted or unsubstituted alkyl group).
And so on. In particular, if the desorbed neutral component is a gas component at the desorption temperature (calcination temperature), it is not incorporated into the carbon material and is in the gas phase portion, so that it is unlikely to become an impurity.

As a typical example, the condensation reaction ((a) above) in which H ₂ O is formed from the −H group and the −OH group and desorbed as the condensation reaction will be described.

One embodiment of the aromatic ring-containing compound (A) in the second embodiment (sometimes referred to as the (X) embodiment) is a compound (a1) having a skeleton consisting of one carbon 6-membered ring structure or two compounds (a1). The above 6-membered ring structure is a compound (a2) having a bonded and / or condensed ring skeleton, and half of the substituents that do not contribute to the structure formation of the skeleton are −OH groups, and the other half. Is an -H group.

In the embodiment (X),
(I) When the aromatic ring-containing compound (A) is a compound (a1) having a skeleton having a single carbon 6-membered ring structure.
(Ii) When the aromatic ring-containing compound (A) is a compound (a2) having a skeleton in which two or more carbon 6-membered ring structures are bonded and / or condensed.
Either of the two cases can be taken.

In the embodiment (X), the "substituent that does not contribute to the structure formation of the skeleton" is the "skeleton composed of one carbon 6-membered ring structure" in the case of the above (i) or the case of the above (ii). Means a substituent that does not contribute to the structure formation of the "skeleton in which two or more carbon 6-membered ring structures are bonded and / or fused". For example, in the case of (i) above, when the compound (a1) having a skeleton composed of one carbon 6-membered ring structure is represented by the chemical formula (a1-1) shown later, it has one carbon 6-membered ring structure. The substituents that do not contribute to the structure formation of the skeleton composed of are 6 −OH groups and 6 −H groups, and the compound (a1) having a skeleton composed of one carbon 6-membered ring structure is shown later. When represented by the chemical formula (a1-2), the substituents that do not contribute to the structure formation of the skeleton consisting of one carbon 6-membered ring structure are three -OH groups and three -H groups. Further, for example, in the case of (ii) above, when the compound (a2) having a skeleton in which two or more carbon 6-membered ring structures are bonded and / or condensed is represented by the chemical formula (a2-1) shown later. The substituents in which two or more carbon 6-membered ring structures do not contribute to the structure formation of the bonded and / or condensed skeleton are 6 -OH groups and 6 -H groups.

In the embodiment (X), half of the number of substituents of the compound (a1) having a skeleton consisting of one carbon 6-membered ring structure that does not contribute to the structure formation of the skeleton is -OH group. Half of the number of substituents of compound (a2) having a skeleton in which two or more 6-membered ring structures are bonded and / or condensed is a −H group, and which does not contribute to the structure formation of the skeleton -OH groups and the other half are -H groups. By having such a substituent configuration, the aromatic ring-containing compound (A) can effectively undergo a dehydration reaction between the same molecules and / or between different molecules by heating.

As the aromatic ring-containing compound (A) that can be adopted in the embodiment (X), a compound (a1) having a skeleton consisting of one carbon 6-membered ring structure or two or more carbon 6-membered ring structures are bonded and /. Alternatively, if it is a compound (a2) having a condensed skeleton, half of the number of substituents that do not contribute to the structure formation of the skeleton are -OH groups, and the other half is -H groups. Any suitable compound may be adopted as long as the effects of the present invention are not impaired. Examples of such an aromatic ring-containing compound (A) include the following compounds.

Among the aromatic ring-containing compounds (A) that can be adopted in the embodiment (X), it is presumed that a condensation reaction is likely to occur due to the formation and desorption of H ₂ O from the -H group and the -OH group, and the temperature is low. Phloroglucinol (compound (a1-2)) and hexahydroxytriphenylene (HHTP) (compound (a2-1)) are preferable in that the reaction is likely to proceed.

Another embodiment of the aromatic ring-containing compound (A) in the second embodiment (sometimes referred to as the (Y) embodiment) is a compound (a1) having a skeleton composed of one carbon 6-membered ring structure and the compound (a1). / Or two or more kinds selected from the compound (a2) having a skeleton in which two or more carbon 6-membered ring structures are bonded and / or fused, and do not contribute to the structure formation of the skeleton of the compound (a1). Half of the total number of substituents and the number of substituents that do not contribute to the structure formation of the skeleton of the compound (a2) are -OH groups, and the other half are -H groups.

In the embodiment (Y),
(I) When the aromatic ring-containing compound (A) is composed of two or more kinds selected from the compound (a1) having a skeleton having one carbon 6-membered ring structure.
(Ii) When the aromatic ring-containing compound (A) consists of two or more selected from the compound (a2) having a skeleton in which two or more carbon 6-membered ring structures are bonded and / or condensed.
(Iii) The aromatic ring-containing compound (A) has one or more selected from the compound (a1) having a skeleton consisting of one carbon 6-membered ring structure and two or more carbon 6-membered ring structures bonded and / or. When it consists of one or more selected from the compound (a2) having a condensed skeleton,
Any of the three cases can be taken.

In the embodiment (Y), what is "the total number of substituents that do not contribute to the structure formation of the skeleton of compound (a1) and the number of substituents that do not contribute to the structure formation of the skeleton of compound (a2)"? , Means as follows. That is, in the case of (i) above, the number of substituents that do not contribute to the structure formation of the “skeleton consisting of one carbon 6-membered ring structure” in each of the two or more compounds (a1) is determined. It means the total number of all. In the case of (ii) above, the substitution of "a skeleton in which two or more carbon 6-membered ring structures are bonded and / or condensed" in each of the two or more compounds (a2) does not contribute to the structure formation of the skeleton. It means the total number of all groups. In the case of the above (iii), the number of substituents that do not contribute to the structure formation of the "skeleton consisting of one carbon 6-membered ring structure" in each of the one or more compounds (a1) and one kind. The number of substituents in each of the above compounds (a2) that did not contribute to the structure formation of the "skeleton in which two or more carbon 6-membered ring structures were bonded and / or condensed" was totaled. Means a number.

In the embodiment (Y), for example, in the case of the above (i), when two or more kinds of compounds (a1) are represented by the following chemical formulas (a1-5) and (a1-6), the chemical formula (a1). The substituents that do not contribute to the structure formation of the skeleton consisting of one carbon 6-membered ring structure of the compound represented by -5) are two -OH groups and four -H groups, and have a chemical formula (a1). The substituents that do not contribute to the structure formation of the skeleton consisting of one carbon 6-membered ring structure of the compound represented by -6) are 4 -OH groups and 2 -H groups, and the sum of them. Is 6 -OH groups and 6 -H groups. Further, for example, in the case of the above (iii), one or more kinds of compounds (a1) are represented by the following chemical formulas (a1-5) and chemical formulas (a1-7), and one or more kinds of compounds (a2) are described below. When represented by the chemical formula (a2-3) of, there are two substituents that do not contribute to the structure formation of the skeleton consisting of one carbon 6-membered ring structure of the compound represented by the chemical formula (a1-5). There are 6 substituents which are -OH group and 4 -H groups and do not contribute to the structure formation of the skeleton consisting of one carbon 6-membered ring structure of the compound represented by the chemical formula (a1-7). There are two substituents that are −OH groups and do not contribute to the structure formation of the skeleton in which two or more carbon 6-membered ring structures of the compound represented by the chemical formula (a2-3) are bonded and / or condensed. -OH groups and 6 -H groups.

By using such an aromatic ring-containing compound as the aromatic ring-containing compound (A), the reaction by its own dehydration reaction occurs without the need for a reaction catalyst, so that the by-products of the chemical reaction and the reaction catalyst are carbon. It is possible to suppress the presence in the material and become a fatal impurity, and it is possible to obtain a higher quality carbon material. Further, by using such an aromatic ring-containing compound, a carbon material can be obtained without using a flammable gas. In addition, such compound (A) can have high reactivity that does not require catalytic action.

<Representative Embodiment of Aromatic Ring-Containing Compound (A) (Embodiment 3)>
A typical embodiment (Embodiment 3) of the aromatic ring-containing compound (A) is a mode in which both the first embodiment and the second embodiment are adopted at the same time. That is, the third embodiment is an aromatic ring-containing compound that decomposes by heating to generate radicals on the aromatic ring, and one neutral molecule is formed from two or more kinds of groups and desorbed by a condensation reaction. It is an aromatic ring-containing compound. Such an aromatic ring-containing compound can cause a condensation reaction between the same molecule and / or between different molecules to become a carbon material.

Specific examples of the structure of the third embodiment include compound (a3-1). In compound (a3-1), carbon dioxide molecules are desorbed by heating to generate radicals (reaction active points) on the aromatic ring, and hydroxyl groups and hydrogen groups are dehydrated between the molecules to cause a condensation reaction.

By using such an aromatic ring-containing compound, the reaction by its own dehydration reaction occurs without the need for a reaction catalyst, so that by-products of the chemical reaction and the reaction catalyst are present in the carbon material. It is possible to suppress becoming a fatal impurity and obtain a higher quality carbon material. Further, by using such an aromatic ring-containing compound, a carbon material can be obtained without using a flammable gas. In addition, such compound (A) can have high reactivity that does not require catalytic action.

≪Carbon material≫
The carbon materials of the present invention show G-band, D-band, G'band by Raman analysis, no graphite-derived peaks by XRD analysis, and the sum of carbon and oxygen in all elements by XPS analysis. The content ratio is 99.9% or more, and the ratio of the content of metals other than nitrogen, sulfur, phosphorus, and alkali metal is 100 ppm or less, respectively, by XRF analysis.

The carbon material of the present invention can be produced by any suitable method as long as the effects of the present invention are not impaired. As such a manufacturing method, preferably, the above-mentioned manufacturing method of the present invention can be mentioned.

The carbon material of the present invention is a novel carbon material different from the conventionally known carbon material. Examples of conventionally known carbon materials include carbon nanotubes, fullerenes, graphite, graphene, graphene oxide, reduced flaphene oxide, artificial graphite, carbon black and the like.

The carbon material of the present invention typically has a honeycomb structure (graphene structure) derived from a benzene ring in its structure. The presence or absence of the graphene structure can be confirmed by Raman spectroscopic analysis described later (see, for example, Non-Patent Document 3).

The carbon material of the present invention shows G band, D band, and G'band by Raman analysis. That is, the carbon material of the present invention, in the Raman spectrum obtained by Raman spectroscopy, (in the range of generally ^{1550cm -1 ~1650cm} -1) G band, D band (typically ^{1300cm -1 ~1400cm} -1 The peak is shown in the G'band (generally in the range of 2650 cm ^-1 to 2750 cm ^-1 ). Showing such a peak in the Raman spectrum obtained by Raman spectroscopy means that the carbon material of the present invention has a graphene structure or a structure similar to the graphene structure, a structure derived from a defect in the graphene structure, or It means that it has a structure similar to the structure derived from the defect of the graphene structure and that it contains a functional group.

In general, if the G band has high strength and is sharp, it can be said that it has a cleaner graphene structure or a structure similar to a graphene structure.

It can be said that the D band generally has a cleaner graphene structure or a structure similar to a graphene structure if the strength is low. In addition, the fact that the D band can be confirmed means that it has a functional group and has a structure derived from a defect in the graphene structure or a structure similar to a structure derived from a defect in the graphene structure. .. As a result, it is possible to exhibit properties different from those of ordinary graphene.

The strength of the G'band is generally strongest when the graphene structure is one layer, and gradually decreases as the number of laminated graphene structures increases. However, the peak of the G'band can be observed even if the intensity gradually decreases as the number of graphene structures laminated increases. Therefore, having a peak in the G'band can be said to have a graphene structure or a structure similar to a graphene structure. The G'band is sometimes also called a 2D band.

Carbon material of the present invention, the Raman analysis, preferably, D + D 'band (in the range of generally ^{2800cm -1 ~3000cm} -1) and / or 2D' band (generally ^{3100cm -1 ~3300cm} -1 Within the range). Showing such a peak in the Raman spectrum obtained by Raman spectroscopy means that the carbon material of the present invention has a graphene structure or a structure similar to the graphene structure, a structure derived from a defect in the graphene structure, or It means that it has a structure similar to the structure derived from the defect of the graphene structure and that it contains a functional group.

It can be said that the D + D'band and the 2D'band generally have a cleaner graphene structure or a structure similar to the graphene structure if the intensity is low. The D + D'band is sometimes also called the D + G band. Further, the fact that the D + D'band and / or the 2D'band can be confirmed means that the band has a functional group and has a structure similar to a structure derived from a defect in the graphene structure or a structure derived from a defect in the graphene structure. That means. As a result, it is possible to exhibit properties different from those of ordinary graphene.

The carbon material of the present invention does not show a peak derived from graphite by XRD analysis. The peak derived from graphite in the present invention means that the peak derived from the (002) plane in XRD is 26.3 degrees or more. Carbon materials that do not have graphite peaks often have broad peaks below 26.3 degrees. This indicates that the carbon material has a wider interlayer distance than graphite and is a material different from graphite. For example, graphite nanoplates (GNP) are thin graphite similar to graphene and show peaks derived from graphite by XRD analysis. The fact that the carbon material of the present invention does not show a peak derived from graphite by XRD analysis means that it is a carbon material different from graphite nanoplates (GNP).

The carbon material of the present invention is substantially free of elements other than carbon and oxygen. Specifically, the carbon material of the present invention has a total content of carbon and oxygen in all elements of 99.9% or more, preferably 99.95% or more, more preferably 99.95% or more by XPS analysis. It is 99.99% or more, more preferably 99.995% or more, particularly preferably 99.999% or more, and most preferably substantially 100%. When the carbon material of the present invention has a total content of carbon and oxygen in all elements measured by XPS analysis within the above range, the purity of the carbon material of the present invention is very high, which hinders physical properties. It means that it does not contain impurities. Further, substantially 100% means that peaks other than carbon and oxygen are not detected in the analysis by XPS (cannot be distinguished from the baseline).

According to XRF analysis, the carbon material of the present invention has a content ratio of a metal other than nitrogen, sulfur, phosphorus, and alkali metal of 100 ppm or less, preferably 50 ppm or less, and more preferably 10 ppm or less. , More preferably 5 ppm or less, particularly preferably 1 ppm or less, and most preferably substantially 0 ppm. The fact that the carbon material of the present invention has a content ratio of a metal other than nitrogen, sulfur, phosphorus, and alkali metal as measured by XRF analysis within the above range means that the carbon material of the present invention has nitrogen and sulfur. It means that it is a carbon material with a very low (extremely high purity) content of impurities such as phosphorus and metals other than alkali metals.

The carbon material of the present invention may exist in bulk. The description of the bulk state is as described above, and typically includes particles, pellets, a film, and the like. Examples of the state of existence of particles include powder. The film is preferably a self-supporting film.

The carbon material of the present invention is a novel carbon material having the above-mentioned characteristics. That is, the carbon material of the present invention has a structure similar to or similar to graphene in terms of crystal structure, and has almost the same structure as reduced graphene oxide in that it is an oxygen-containing carbon material having almost a single layer. However, it differs from reduced graphene in that it contains substantially no elements other than carbon and oxygen, and also differs from graphite in crystal structure in that it contains metals other than nitrogen, sulfur, phosphorus, and alkali metals. It is a novel carbon material that has a very low proportion (ie, very high purity) and can exist in bulk.

The carbon material of the present invention has a structure derived from a defect in the graphene structure or a structure similar to a structure derived from a defect in the graphene structure. The presence of such defects can contribute to the development of solubility, dispersibility, etc. in the solvent or resin of the carbon material of the present invention.

≪Carbon material composition≫
The carbon material composition of the present invention contains the carbon material of the present invention. Since the carbon material of the present invention has a structure derived from a defect in the graphene structure or a structure similar to a structure derived from a defect in the graphene structure, it can exhibit solubility, dispersibility, etc. in a solvent or resin. .. Therefore, when the carbon material of the present invention and the solvent are blended, a dispersion or a solution to the solvent can be obtained, and when the carbon material of the present invention and the resin are blended, the dispersion or the composition uniformly dissolved in the resin is obtained. It is possible to obtain products and develop applications in various fields.

The content ratio of the carbon material of the present invention in the carbon material composition of the present invention can be appropriately set according to the purpose. Such a content ratio is typically preferably 0.01% by weight to 99.9% by weight.

One embodiment of the carbon material composition of the present invention comprises a solvent. As one of the preferred embodiments of the carbon material composition of the present invention, the carbon material is dispersed in the solvent.

One embodiment of the carbon material composition of the present invention comprises a resin. As one of the preferred embodiments of the carbon material composition of the present invention, the carbon material is dispersed in the resin.

Examples of the solvent that can be contained in the carbon material composition of the present invention include amide solvents such as NMP (N-methylpyrrolidone) and DMF (N, N-dimethylformamide), ketone solvents such as acetone, and 2-propanol. Etc., such as alcohol solvents. Such a solvent may be only one kind or two or more kinds.

Examples of the resin that can be contained in the carbon material composition of the present invention include rubber-based resins such as SBR, general-purpose epoxy resins, phenol resins, polyimides, and polyamide resins. Such a resin may be only one kind or two or more kinds.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. Unless otherwise specified, "part" means "part by weight" and "%" means "% by weight". Further, in the present specification, "weight" may be read as "mass".

<Raman spectroscopic analysis>
Raman spectroscopic analysis was performed with the following equipment and conditions.
Measuring device: Microscopic Raman (JASCO NRS-3100)
Measurement conditions: 532 nm laser used, objective lens 20 times, CCD capture time 1 second, integration 64 times (resolution = 4 cm-1)

<XRD analysis>
The XRD measurement was performed using a fully automatic horizontal X-ray diffractometer (SMART LAB manufactured by Rigaku Co., Ltd.) under the following conditions.
CuKα1 wire: 0.15406 nm
Scanning range: 10 ° -90 °
X-ray output setting: 45kV-200mA
Step size: 0.020 °
Scan speed: 0.5 ° min ^-1 -4 ° min ^-1
The XRD measurement was carried out in a state where the inert atmosphere was maintained by loading the sample into an airtight sample table in the glove box.

<XRF analysis>
The XRF measurement was performed by a calibration curve method using a fluorescent X-ray analyzer (PW2404 manufactured by Philips). Those having an element concentration of 0.01% or more were read as each component. Since hydrogen was not detected, the total amount of elements other than hydrogen was calculated as 100%.

<XPS analysis>
The XPS measurement was performed using a photoelectron spectrometer (JPS-9000MX, manufactured by JEOL Ltd.). Since hydrogen was not detected, the total amount of elements other than hydrogen was calculated as 100%.

[Example 1]
Phloroglucinol manufactured by Tokyo Chemical Industry Co., Ltd. was calcined at 1300 ° C. for 1 hour in a nitrogen atmosphere using SUPER BOY manufactured by Marusho Electric Co., Ltd. The Raman analysis result of the obtained carbon material is shown in FIG. 1, and the XRD analysis result is shown in FIG. Moreover, in the analysis by XPS, it was substantially only carbon and oxygen elements, and in the analysis by XRF, the elements other than oxygen and carbon were 100 ppm or less.

[Comparative Example 1]
Graphene oxide was prepared with reference to Patent Document WO2017 / 082262. After adjusting the obtained graphene oxide to a concentration of 0.2% by weight with water, 5 equivalents of L-ascorbic acid manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. was added to graphene oxide, and the mixture was reacted at 70 ° C. for 2 hours. .. After the reaction, the reaction solution was repeatedly washed with water and filtered, and then washed and filtered with acetone. The obtained wet cake was vacuum dried to obtain reduced graphene oxide. The Raman analysis results of the obtained carbon material (reduced graphene oxide) are shown in FIG. 3, and the XRD analysis results are shown in FIG. Further, in the analysis by XRF, sulfur was 321 ppm and manganese was 207 ppm.

[Comparative Example 2]
The XRD analysis result of the exfoliated graphene (Graphene nanoplatates aggregates) manufactured by STREM is shown in FIG. It can be seen that exfoliated graphene (GNP) has a strong graphite peak and cannot be said to be graphene.

The carbon material obtained by the production method of the present invention, the carbon material of the present invention, and the carbon material composition of the present invention can be used as novel functional materials in various fields due to their characteristic physical properties.

Claims (14)

It is a method of manufacturing carbon materials.
An aromatic ring-containing compound (A) having a molecular weight of 500 or less, which is composed of carbon, hydrogen, and oxygen, is calcined at a temperature of 700 ° C. or higher.
Manufacturing method of carbon material. The method for producing a carbon material according to claim 1, wherein the condensation reaction temperature of the aromatic ring-containing compound (A) is 400 ° C. or lower. When TG-DTA analysis of the aromatic ring-containing compound (A) was performed under a nitrogen gas atmosphere from 40 ° C. under a temperature rising condition of 10 ° C./min, the temperature was 500 ° C. with respect to the initial weight M50 at a temperature of 50 ° C. The method for producing a carbon material according to claim 1 or 2, wherein the weight ratio (M500 / M50) of the weight M500 is 0.2 or more. The method for producing a carbon material according to any one of claims 1 to 3, wherein the aromatic ring-containing compound (A) is an aromatic compound having a hydroxyl group. The method for producing a carbon material according to any one of claims 1 to 4, wherein the firing temperature is 1000 ° C to 1500 ° C. The method for producing a carbon material according to any one of claims 1 to 5, which can be produced in a bulk state. It is a carbon material
Raman analysis shows G band, D band, G'band,
XRD analysis showed no graphite-derived peaks
XPS analysis showed that the total content of carbon and oxygen in all elements was 99.9% or higher.
According to XRF analysis, the proportions of the contents of metals other than nitrogen, sulfur, phosphorus, and alkali metals are 100 ppm or less, respectively.
Carbon material. The carbon material of claim 7, which exhibits a D + D'band and / or a 2D'band by Raman analysis. The carbon material of claim 7 or 8, which may be present in bulk. A carbon material composition comprising the carbon material according to any one of claims 7 to 9. The carbon material composition according to claim 10, which comprises a solvent. The carbon material composition according to claim 11, wherein the carbon material is dispersed in the solvent. The carbon material composition according to claim 10 or 11, which comprises a resin. The carbon material composition according to claim 13, wherein the carbon material is dispersed in the resin.

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