JP4010974B2 - Method for producing vapor grown carbon fiber - Google Patents

Description

【００６１】
【表２】

【００６２】
【発明の効果】
上述したように本発明によれば、触媒をあらかじめ担持する等の前処理を必須とせず、特定の添加成分を反応系に供給し、条件を調製するだけで、触媒粒子の凝集、粗大化を抑制でき、担持法と比較して、大幅な工程短縮が可能となり経済的であるのみならず、極めて少量の触媒量で高収率に炭素繊維を得ることができ、安価に炭素繊維を製造することが可能になる。
【図面の簡単な説明】
【図１】気相法炭素繊維を製造するための横型反応装置の一般例を示す模式断面図である。
【図２】実施例１〜７、９〜１１、比較例１、３、４で気相法炭素繊維を製造した反応装置を示す模式断面図である。
【図３】実施例８で気相法炭素繊維を製造した反応装置を示す模式断面図である。
【図４】比較例２で使用した原料導入部に加熱ヒーターを有する気相法炭素繊維を製造するための反応装置を示す模式断面図である。
【図５】実施例１０、１１、比較例４で使用した２重管ノズルを示す模式断面図である。
【図６】実施例１〜７、９、比較例１、３で使用した３重管ノズルを示す模式断面図である。
【符号の説明】
１…原料噴霧ノズル
２…石英製反応管
３…ヒーター
４…捕集器
５…気化ヒーター
６…プレート
７…気化器
８…キャリアガス（内側）
９…反応液
１０…キャリアガス（外側）
１１…内管
１２…外管
１３…中管[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for efficiently producing vapor-grown carbon fibers such as carbon nanotubes.
[0002]
[Prior art]
Carbon fibers obtained by the vapor growth method are collectively referred to as VGCF (vapor growth carbon fibers), and since they have characteristics such as being able to easily obtain those having a high aspect ratio, they have been actively studied. Therefore, there are many reports on manufacturing methods. In recent years, carbon nanotubes that have attracted particular attention (that is, carbon fibers having a fiber diameter on the order of nanometers) can also be synthesized by application of this vapor phase growth method.
[0003]
FIG. 1 is a schematic cross-sectional view showing an example of a reaction apparatus for continuously producing carbon fibers by a vapor deposition method. As an example of a general production method, CO, methane, acetylene, ethylene, benzene, toluene or the like is used as a raw material hydrocarbon. When the raw material hydrocarbon is a gas at normal temperature, it is mixed and supplied as a gas with a carrier gas, and when it is a liquid, it is vaporized and then mixed with the carrier gas to be supplied or sprayed in a liquid state on the heating zone. As the carrier gas, an inert gas such as nitrogen gas or reducing hydrogen gas is used. As the catalyst, a supported catalyst in which a metal is supported on a carrier such as alumina or an organometallic compound such as ferrocene is used. When a supported catalyst is used, the supported catalyst is placed in the reaction zone in advance and heated to perform the necessary pretreatment, and then the raw material hydrocarbons are supplied and reacted (example shown in FIG. 1) or pretreatment. The supported catalyst is supplied continuously or pulsed from outside the system to carry out the reaction. In addition, an organometallic compound such as ferrocene, which is a homogeneous catalyst precursor compound, is fed continuously or in pulses to the heating zone together with the raw material hydrocarbon to catalyze metal particles generated by thermal decomposition of the catalyst precursor compound. Carbon fibers can also be produced. The product is collected inside the heating zone or in the collector 4 at the end thereof, and collected after a predetermined time of reaction.
[0004]
The method for producing carbon fiber by the gas phase method is roughly classified into the following three types depending on the method of supplying the catalyst or the precursor compound of the catalyst.
(A) A substrate or boat made of alumina or graphite carrying a catalyst or its precursor compound is placed in a heating zone and brought into contact with a hydrocarbon gas supplied from a gas phase;
(B) A catalyst or its precursor compound particles dispersed in a liquid hydrocarbon or the like and continuously or pulsed from outside the system to be brought into contact with the hydrocarbon at a high temperature; and
(C) A metallocene or carbonyl compound that dissolves in a liquid hydrocarbon is used as a catalyst precursor compound, and a hydrocarbon in which the catalyst precursor compound is dissolved is supplied to a heating zone, whereby the catalyst and the hydrocarbon are heated to a high temperature. Things to contact with.
[0005]
Among these, in particular, according to the synthesis by the method (c), it is possible to obtain a product continuously and stably, so that the production of VGCF on an industrial scale is possible by using this method. It has become. In the method (b), which can be continuously produced, a suspension in which a surfactant is added for the purpose of stabilizing the ratio of the amount of hydrocarbon and catalyst to be supplied is 6-65765; Patent Document 1), a solution in which catalyst fine particles having a uniform nano-order particle size synthesized using a microemulsion are suspended in a hydrocarbon such as toluene are continuously supplied to a heating zone. It has also been reported that single-walled carbon nanotubes can be synthesized (Chemical Industry Daily 2001.10.15; Non-Patent Document 1).
[Patent Document 1]
JP 6-65765
[Non-Patent Document 1]
Chemical Industry Daily 2001.10.15
[0006]
[Problems to be solved by the invention]
However, in the method (a), a catalyst or a precursor thereof is applied to a substrate, a pretreatment such as reduction is performed as necessary, a carbon fiber is then manufactured, and the process needs to be performed independently after being cooled. Therefore, continuous production is difficult and therefore productivity is low. In addition, many steps of preparation of the catalyst, application to the substrate, pre-reduction treatment to a metal state, generation of carbon fiber, and recovery of the carbon fiber from the substrate are necessary, which is not economical.
[0007]
On the other hand, in the above methods (b) and (c), although continuous production is possible, a sufficient amount of carbon fiber can be obtained unless the catalyst or its precursor compound is used in a large excess compared to the required amount. There is a tendency not to be obtained. For this reason, not only is an expensive catalyst or catalyst precursor compound wasted, but also a process for removing an excessively added catalyst-derived byproduct is required, resulting in a loss of economy. Thus, a process for producing a large amount of vapor-grown carbon fiber at a low cost has not been developed, which has been a cause of hindering the production of vapor-grown carbon fiber on an industrial scale.
An object of the present invention is to provide a method capable of producing a carbon fiber at a low cost with a simple process, high catalyst efficiency.
[0008]
[Means for Solving the Problems]
As a result of intensive studies to solve the above-mentioned problems, the present inventor selected a certain condition together with a specific additive component in addition to a carbon compound and a catalyst precursor compound as raw materials for carbon fiber, and supplied them to the heating zone. In this case, the present inventors have found that carbon fibers can be obtained in a high yield even when a small amount of catalyst is used (an amount that is impossible under conventional conditions), and the present invention has been completed.
Although the mechanism of the present invention has not yet been fully elucidated, according to the knowledge of the present inventor, at least a part of the additive component is present as a solid or liquid in the heating zone, and the catalyst or catalyst precursor is present. By coexisting with the compound, it is presumed that aggregation and coarsening of the catalyst particles generated in the heating zone are suppressed, and as a result, it is possible to express and maintain the catalytic activity necessary for growing the carbon fiber.
According to the present invention, as compared with a conventional method in which a particulate (solid state) catalyst supported on a support such as alumina is prepared in advance and supplied to the heating zone. Thus, by adding a specific additive component without adding a plurality of complicated steps such as a catalyst preparation step and separation of the produced carbon fiber and the catalyst carrier, an effect equal to or higher than that obtained when a supported catalyst is used. Since it can be obtained in a single process, it is very economical.
[0009]
That is, the present invention relates to the following [1] to [21], for example.
[1] A method for continuously producing carbon fibers in a gas phase by contacting a carbon compound with a catalyst and / or a catalyst precursor compound in a heating zone; heating the carbon compound, the catalyst precursor compound and the additive component A method for producing vapor-grown carbon fiber, characterized by being supplied to a zone and reacting under reaction conditions in which at least a part of an additive component is present as a solid or liquid in the heating zone.
[0010]
[2] The method for producing vapor grown carbon fiber according to [1], wherein the reaction conditions are at least one selected from the temperature of the heating zone, the residence time, the supply concentration of the additive component, and the supply method of the reaction raw materials.
[0011]
[3] The method for producing vapor grown carbon fiber according to [1] or [2], wherein the additive component is supplied to the heating zone in a liquid state, a solution state, or a liquid dispersed state.
[4] Production of vapor-grown carbon fiber according to [1] or [2], wherein the catalyst precursor compound and the additive component are dissolved or dispersed in the same liquid which may be a carbon source and supplied to the heating zone Method.
[5] The gas phase method according to [1] or [2], wherein the catalyst precursor compound is in a gaseous state and the additive component is dissolved or dispersed in the same liquid which may be a carbon supply source and supplied to the heating zone A method for producing carbon fiber.
[6] The method for producing vapor grown carbon fiber according to any one of [3] to [5], in which a liquid component containing an additive component is supplied using a spray nozzle installed at an inlet portion of the reaction tube.
[7] The method for producing vapor grown carbon fiber according to [6], wherein the temperature of the discharge part of the spray nozzle is 200 ° C. or lower.
[8] The method for producing vapor grown carbon fiber according to [6], wherein a discharge speed of a liquid component including an additive component and a gas component such as a carrier gas is 30 m / min or less in a discharge portion of a spray nozzle.
[0012]
[9] The method for producing vapor grown carbon fiber according to any one of [1] to [8], wherein the additive component is an organic compound or an organic compound polymer.
[10] Vapor grown carbon according to any one of [1] to [8], wherein the additive component is at least one compound selected from the group of additive component (1) to additive component (3) below: A method for producing fibers.
Additive component (1): Inorganic compound whose boiling point or decomposition temperature is lower is 180 ° C. or higher
Additive component (2): Organic compound whose boiling point or decomposition temperature is lower is 180 ° C. or higher
Additive component (3): organic compound polymer having a molecular weight of 200 or more
[0013]
[11] The vapor grown carbon according to [10], wherein the additive component (1) is an inorganic compound containing at least one element selected from the group consisting of Group 2 to 15 elements in the Group 18 element periodic table A method for producing fibers.
[12] The additive component (1) is Mg, Ca, Sr, Ba, Y, La, Ti, Zr, Cr, Mo, W, Fe, Co, Ni, Cu, Zn, B, Al, C, Si, Bi The method for producing vapor grown carbon fiber according to [10], which is an inorganic compound containing at least one element selected from the group consisting of:
[13] The active ingredient (1) is powdered activated carbon, graphite, silica, alumina, magnesia, titania, zirconia, zeolite, calcium phosphate, aluminum phosphate or an aspect ratio of 1 to 50 and an average fiber diameter of 10 to 300 nm [10] The method for producing vapor grown carbon fiber according to [10], which is at least one selected from carbon fibers of [10].
[0014]
[14] The method for producing vapor grown carbon fiber according to [10], wherein the additive component (2) is an organic compound containing at least one element selected from the group consisting of oxygen, nitrogen, sulfur and phosphorus.
[15] Additive component (2) is halogenated ethylenes, dienes, acetylene derivatives, styrene derivatives, vinyl ester derivatives, vinyl ether derivatives, vinyl ketone derivatives, acrylic acid derivatives, methacrylic acid derivatives, acrylic acid ester derivatives, methacrylic acid ester derivatives , Acrylamide derivatives, methacrylamide derivatives, acrylonitrile derivatives, methacrylonitrile derivatives, maleic acid derivatives, maleimide derivatives, vinylamine derivatives, phenol derivatives, melamines, urea derivatives, amine derivatives, carboxylic acid derivatives, carboxylic acid ester derivatives, diol derivatives, The method for producing vapor grown carbon fiber according to [10], which is at least one organic compound selected from the group consisting of a polyol derivative, an isocyanate derivative and an isothiocyanate derivative. .
[0015]
[16] The method for producing vapor grown carbon fiber according to [10], wherein the additive component (3) is an organic compound polymer containing at least one element selected from the group consisting of oxygen, nitrogen, sulfur and phosphorus.
[17] Additive component (3) is olefins, halogenated ethylenes, dienes, acetylene derivatives, styrene derivatives, vinyl ester derivatives, vinyl ether derivatives, vinyl ketone derivatives, acrylic acid derivatives, methacrylic acid derivatives, acrylic acid ester derivatives, methacrylic acid Acid ester derivatives, acrylamide derivatives, methacrylamide derivatives, acrylonitrile derivatives, methacrylonitrile derivatives, maleic acid derivatives, maleimide derivatives, vinylamine derivatives, phenol derivatives, melamines / urea derivatives, amine derivatives, carboxylic acid derivatives, carboxylic acid ester derivatives, [10] The polymer of at least one organic compound selected from the group consisting of a diol derivative, a polyol derivative, an isocyanate derivative, and an isothiocyanate derivative. The process for producing a vapor-grown carbon fiber.
[0016]
[18] The method for producing vapor grown carbon fiber according to [1], wherein the catalyst precursor compound is a compound that can become a gas in the heating zone.
[19] The vapor grown carbon fiber according to [1], wherein the catalyst precursor compound contains at least one metal selected from Groups 3, 5, 6, 8, 9, and 10 in the Group 18 element periodic table Manufacturing method.
[0017]
[20] The vapor grown carbon fiber according to [19], wherein the mass ratio of the additive component to the metal atom in the catalyst precursor compound (additive component / metal atom in the catalyst precursor compound) is 0.001 to 10,000. Manufacturing method.
[21] A vapor-grown carbon fiber produced by the production method according to any one of [1] to [20].
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described more specifically with reference to the drawings as necessary. In the following description, “parts” and “%” representing the quantity ratio are based on mass unless otherwise specified.
[0019]
(Carbon compound)
In the carbon fiber production method of the present invention, the carbon compound that is the raw material of the carbon fiber is not particularly limited. As this carbon compound, CCl _Four , CHCl _Three , CH ₂ Cl ₂ , CH _Three Cl, CO, CO ₂ , CS ₂ In addition to these, all organic compounds can be used. Particularly useful compounds include CO and CO. ₂ Mention may be made of aliphatic hydrocarbons and aromatic hydrocarbons. In addition to these, carbon compounds containing elements such as nitrogen, phosphorus, oxygen, sulfur, fluorine, chlorine, bromine and iodine can also be used.
[0020]
Examples of preferred carbon compounds include CO, CO ₂ Inorganic gases such as methane, ethane, propane, butane, pentane, hexane, heptane, octane, etc .; Alkenes such as ethylene, propylene, butadiene; Alkynes such as acetylene; benzene, toluene, xylene, styrene, etc. Monocyclic aromatic hydrocarbons; polycyclic compounds having condensed rings such as indene, naphthalene, anthracene, phenanthrene; cycloparaffins such as cyclopropane, cyclopentane, cyclohexane; cyclopentene, cyclohexene, cyclopentadiene, dicyclopentadiene, etc. And cycloaliphatic hydrocarbon compounds having a condensed ring such as steroid. Furthermore, these hydrocarbons contain oxygen, nitrogen, sulfur, phosphorus, halogen, etc., for example, oxygen-containing compounds such as methanol, ethanol, propanol, butanol, methylthiol, methylethyl sulfide, dimethylthioketone, etc. Sulfur-containing aliphatic compounds, sulfur-containing aromatic compounds such as phenylthiol and diphenyl sulfide, sulfur-containing or nitrogen-containing heterocyclic compounds such as pyridine, quinoline, benzothiophene, and thiophene, chloroform, carbon tetrachloride, chloroethane, trichloroethylene, etc. Although not a simple substance, natural gas, gasoline, kerosene, heavy oil, creosote oil, kerosene, turpentine oil, camphor oil, pine oil, gear oil, cylinder oil and the like can also be used. It is of course possible to use a mixture of these.
More preferred carbon compounds include CO, methane, ethane, propane, butane, ethylene, propylene, butadiene, acetylene, benzene, toluene, xylene and mixtures thereof.
[0021]
(catalyst)
The catalyst in the present invention is not particularly limited as long as it is a substance that promotes the growth of carbon fibers. Examples of the catalyst include at least one metal selected from the group consisting of groups 3 to 12 in the group 18 element periodic table recommended by IUPAC in 1990. Furthermore, at least one metal selected from the group consisting of 3, 5, 6, 8, 9, 10 is preferable, and iron, nickel, cobalt, ruthenium, rhodium, palladium, platinum and rare earth elements are particularly preferable.
[0022]
(Catalyst precursor compound)
The catalyst precursor compound is a compound that is thermally decomposed in a heating zone and is further reduced in some cases to give the catalyst. For example, ferrocene, which is a catalyst precursor compound, is thermally decomposed in a heating zone to produce iron fine particles that are a catalyst. Therefore, as the catalyst precursor compound, a compound that gives a metal as described above can be suitably used. More specifically, for example, as a catalyst precursor compound, a metal compound containing at least one element selected from the group consisting of groups 3 to 12, and further a group consisting of groups 3, 5, 6, 8, 9, 10 A compound containing at least one element selected from the group consisting of iron, nickel, cobalt, ruthenium, rhodium, palladium, platinum and a rare earth element is most preferred.
[0023]
In addition, since the catalyst precursor compound is preferably a gas that can become a gas in the heating zone, organometallic compounds such as ferrocene, carbonyl compounds, chlorides, and the like are preferably used. In addition, a metal compound containing at least one element selected from the group consisting of groups 1 to 17 as a main component is added as a catalyst modifying component (so-called promoter) to modify the catalytic performance of the main component metal. It is also possible. It is preferable that this modifying component also becomes a gas in the heating zone.
The method for supplying these catalyst precursor compounds to the heating zone is not particularly limited, but the catalyst precursor compounds can be supplied in a gaseous state or dissolved in a solvent or the like. Although there is no restriction | limiting in particular in the solvent to be used, What is necessary is just to select suitably what can melt | dissolve the quantity of catalyst precursor compounds to supply, and water, alcohol, hydrocarbon, ketone, ester etc. can be used. Use of a carbon compound such as benzene, toluene or xylene is preferable because the solvent itself can be used as a carbon compound as a carbon source.
[0024]
It is also possible to disperse a solid catalyst precursor compound that is substantially insoluble in the solvent into a gas or a liquid and supply it to the heating zone. In this case, adding a surfactant or the like to make a good suspension is recommended. However, since the solid catalyst precursor compound generally does not easily become gaseous in the heating zone, the degree of suitability tends to be slightly lower from this point. The use of a catalyst precursor compound that can be a gas in the heating zone is desirable because the catalyst is uniformly dispersed and adsorbed or included in the additive component.
[0025]
The addition amount of the catalyst precursor compound is preferably 0.000001 to 1, preferably 0.00001 to 0 as a ratio with respect to the total number of moles of carbon atoms in the raw material (that is, the number of moles of carbon atoms in the raw material such as a carbon compound). .1 is more preferable, and 0.0001 to 0.005 is optimal. If it is less than 0.000001, the catalyst is insufficient and the number of fibers decreases or the fiber diameter increases, which is not preferable. If this ratio is greater than 1, it is not preferable because it is not economical, and coarsened catalyst particles that did not function as a catalyst are mixed in the fiber. In the calculation of the total carbon atom mole ratio in the above raw material, the calculation of the total carbon atom mole number includes not only the carbon compound but also the carbon atoms derived from the catalyst precursor compound, the additive component, and the solvent.
[0026]
(Conditions present as solid or liquid phase)
A feature of the present invention is that in addition to the carbon compound and the catalyst precursor compound, a specific additive component is supplied to the heating zone (by setting the conditions so that at least a part of the heating zone exists as a solid phase or a liquid phase). In the point. By allowing the additive component to coexist, a significant amount of carbon fiber grows even with a very small amount of catalyst, and it is possible to expect an improvement in the quality of the obtained fiber such as fiber diameter distribution.
Although the role of this additive component is not necessarily clear, it prevents the catalyst particles from agglomerating and coarsening in the heating zone, and as a result, it is possible to effectively express and maintain the activity of the catalyst. It is guessed.
Such an effect of the present invention makes it possible to obtain carbon fibers in a high yield even with a small amount of catalyst that could not be obtained conventionally. Regarding the mechanism of action, the following estimation is possible. That is, the catalyst particles generated from the catalyst precursor compound in the heating zone are adsorbed on the surface of the additive or taken into the additive, thereby preventing the catalyst particles from colliding with each other and aggregating and coarsening. The Therefore, in the absence of added components, a sufficient amount of fiber is produced even with a very small amount of catalyst that cannot provide a significant number of catalyst particles.
[0027]
In addition, the present invention does not include a method in which a metal such as iron or cobalt having catalytic ability to generate carbon fibers is supported on a carrier such as alumina and then supplied to the reactor, which has been conventionally practiced. Although it is possible to use finely divided alumina or the like as an additional component, the present invention does not perform the act of immobilizing the catalyst precursor compound on the support such as intentionally supporting the catalyst precursor compound on alumina, Basically, the catalyst precursor compound is not immobilized by chemical interaction such as adsorption, inclusion or even chemical bond formation with the added components, but each is supplied to the heating zone of the reactor in an independent state. There is a special feature. For example, when ferrocene is used as a catalyst precursor compound and activated carbon is used as an additive component and both are dispersed in benzene as a solvent and supplied to the reactor, ferrocene is selectively adsorbed and concentrated on the activated carbon. However, it is used only in a state where both are uniformly dispersed in benzene.
[0028]
(Raw material supply method)
The raw material supply method is not particularly limited. That is, as a raw material supply method, (a) the catalyst precursor compound and the additive component are both dissolved or dispersed in a solvent, or (b) the catalyst precursor compound is vaporized and vaporized. Various embodiments are possible in which the additive component is supplied in a state of being dissolved or dispersed in a solvent, or (c) the catalyst precursor compound is supplied in a gas state and the additive component is supplied in a solid phase. In the present invention, the former two (that is, the method (a) or the method (b)) are preferable.
[0029]
Further, in the present invention, it is meaningful to perform a process for forming chemical interaction such as adsorption and inclusion of the catalyst component on the additive component in the reactor. That is, when the catalyst is previously supported on the support, the particle size and particle size distribution of the catalyst greatly depend on the characteristics of the support itself such as the support conditions and pore distribution, and the complicated catalyst preparation process, catalyst hydrogen reduction, etc. It is necessary to provide a pretreatment step for the catalyst. On the other hand, in the present invention, in addition to omitting catalyst preparation and pretreatment steps, catalyst particles having a size effective for carbon fiber growth can be generated more efficiently. Carbon fiber can be produced.
[0030]
(Reaction in heating zone)
A characteristic to be provided by the additive component is that at least a part of the additive component is present in a solid phase or a liquid phase in a heating zone of a reactor for producing carbon fibers. Further, the role of the additive component is to suppress the aggregation of the catalyst particles at the initial stage of the reaction. Once the growth of the carbon fiber starts, the catalyst particle is included in the carbon fiber, so that the role of the additive component ends. Therefore, it can be considered that it may be vaporized or decomposed in the later stage of the reaction.
Usually, the reaction for converting a carbon compound into carbon fiber is performed at a high temperature of about 1000 ° C. and in a special carrier gas atmosphere such as hydrogen for a residence time on the order of seconds. For this reason, a compound that can be partly present in solid or liquid under these conditions is selected as the additive component, and at least part of the additive component can be present as solid or liquid in the heating zone. It is necessary to adjust reaction conditions such as temperature, residence time, and atmosphere. This reaction condition cannot be determined uniquely because it varies depending on the carbon compound used, the type of the desired product, and the like.
[0031]
Examples of the normal range of reaction conditions include temperature: 500 to 1500 ° C., residence time: 0.001 to 100 seconds, atmosphere (carrier gas): inert gas such as nitrogen or argon, or hydrogen gas having reducibility. . It is possible to add a trace amount of oxygen as necessary. The important thing is that the phase at a very short residence time is a problem in a special atmosphere from a general sense, so it goes without saying that compounds with boiling points above the reaction temperature apply, even if the boiling point below the reaction temperature or Even a compound having a decomposition temperature satisfies a necessary condition unless it is completely vaporized or decomposed within the residence time. Therefore, parameters such as boiling point and vapor pressure are helpful to some extent, but are not likely to be absolute scales. Rather, it is more practical to observe how the compound exists under the actual reaction conditions. For this purpose, the compound itself or a compound dissolved or dispersed in an appropriate solvent such as water (preferably water in the sense that no carbide remains) is exposed to an atmosphere set in actual reaction conditions to form a solid or It is preferable to confirm that the liquid remains. Even if it is exposed to such conditions, it may be a part without vaporizing or decomposing, so that a compound remaining as a solid or liquid can be defined as an effective additive component in the present invention.
Even once vaporized, if the temperature drops, it can be liquefied or solidified again. Therefore, the recovery zone must be provided in the immediate vicinity of the heating zone, for example, at a temperature maintained at 100 ° C or higher, preferably 200 ° C or higher. . However, when the additive component is not water-soluble and a hydrocarbon-based solvent is used, the solvent itself is carbonized and remains as a solid, which makes it difficult to distinguish the additive component from the residue. As described above, it may be difficult to determine that all of the additive components are not vaporized in the above test, but basically an index for determining whether or not the compound functions most effectively is determined by this method. give.
[0032]
Furthermore, even when the same additive component is used, as shown in Example 4 and Comparative Example 2 described later, when the additive component is introduced into the heating zone by being dissolved in a solvent, an effect is recognized. The reaction conditions, including the raw material supply method, may not be effective when a vaporization zone is provided and the liquid containing the additive component is vaporized by supplying the vaporization zone and then introduced into the reactor. The situation below is a problem.
[0033]
Chemical handbook basic revision 4th edition The Chemical Society of Japan (Maruzen Co., Ltd., published in 1993), CRC Handbook of Chemistry and Physics (CRC Press Inc.), etc. It is very useful as a standard for discriminating additive components suitable for the above. For example, when a boiling point at normal pressure or a sample of about 10 mg is heated at 10 ° C./min in an inert gas atmosphere using a thermal analyzer, the temperature at which 50% weight loss (decomposition temperature) occurs, whichever is lower Is an inorganic compound having a temperature of 180 ° C. or higher, preferably 300 ° C. or higher, more preferably 450 ° C. or higher, most preferably 500 ° C. or higher, the boiling point at normal pressure or the decomposition temperature, whichever is lower, preferably 180 ° C. or higher Is an organic compound having a molecular weight (number average molecular weight after polymerization) of 200 or more, preferably 300 or more, more preferably 400 or more, an organic compound polymer, etc. Can be used as an additive component of the present invention. In addition, the additive component is decomposed by heating, and the boiling point or decomposition temperature, whichever is lower, is converted to an inorganic compound having a temperature of 180 ° C. or higher, preferably 300 ° C. or higher, more preferably 450 ° C. or higher, most preferably 500 ° C. or higher. It may be a compound.
(Measurement of decomposition temperature)
In the measurement of the decomposition temperature described above, for example, as shown in the examples described later, about 10 mg of a sample is obtained at a nitrogen gas flow rate of 200 cc / min using a differential thermal analyzer (Seiko Instruments DTA-TG SSC / 5200). Heating to 600 ° C. at a rate of temperature increase of 10 ° C./min can be made the decomposition temperature by reading the temperature at which a 50% by weight loss has occurred.
[0034]
(Additive component (1))
An example of an inorganic compound useful as the additive component (1) is an inorganic compound containing at least one element selected from the group consisting of Group 2 to 15 elements in the group 18 element periodic table, more preferably Mg, Ca Inorganic containing at least one selected from the group consisting of Sr, Ba, Y, La, Ti, Zr, Cr, Mo, W, Fe, Co, Ni, Cu, Zn, B, Al, C, Si, Bi A compound can be suitably used. Although these metals can be used alone, they are generally unstable and have problems in handling and stability, so it is recommended to use them as oxides, nitrides, sulfides, carbides and their double salts. Is done. Further, sulfates, nitrates, acetates, hydroxides and the like that can be decomposed by heating to become these compounds can be mentioned. Furthermore, carbon may be used alone, and activated carbon, graphite and the like can be used effectively. Furthermore, it is possible to use the carbon fiber itself as an additive component, but in consideration of the convenience at the time of supply, those having a large aspect ratio are not suitable, the aspect ratio is 1 to 50 and the average fiber diameter is What is 10 nm or more and 300 nm or less is preferable. The aspect ratio can be obtained from an average value of fiber length / fiber diameter by measuring the fiber diameter and fiber length of 100 or more fibers using an electron micrograph.
[0035]
These inorganic compounds include zinc oxide, aluminum oxide, calcium oxide, chromium oxide (II, III, VI), cobalt oxide (II, III), cobalt oxide (II) aluminum, zirconium oxide, yttrium oxide, silicon dioxide, Strontium oxide, tungsten oxide (IV, VI), titanium oxide (II, III, IV), iron oxide (II, III), iron (III) zinc oxide, iron (III) cobalt (II), iron oxide (III) ) Iron (II), iron (III) copper (II), copper oxide (I, II), iron (III) barium, nickel oxide, nickel (II) iron (III), barium oxide, barium aluminum oxide Bismuth oxide (III), bismuth oxide (IV) dihydrate, bismuth oxide (V), bismuth oxide (V) Hydrate, magnesium oxide, magnesium aluminum oxide, magnesium iron (III) oxide, molybdenum oxide (IV, VI), lanthanum oxide, lanthanum iron oxide, zinc nitride, aluminum nitride, calcium nitride, chromium nitride, zirconium nitride, titanium nitride , Iron nitride, copper nitride, boron nitride, zinc sulfide, aluminum sulfide, calcium sulfide, chromium sulfide (II, III), cobalt sulfide (II, III), titanium sulfide, iron sulfide, copper sulfide (I, II), sulfide Nickel, barium sulfide, bismuth sulfide, molybdenum sulfide, zinc sulfate, zinc ammonium sulfate, aluminum sulfate, ammonium aluminum sulfate, ammonium chromium sulfate, yttrium sulfate, calcium sulfate, chromium sulfate (II, III), cobalt sulfate (II), titanium sulfate ( III IV), iron sulfate (II, III), ammonium iron sulfate, copper sulfate, nickel sulfate, nickel ammonium sulfate, barium sulfate, bismuth sulfate, magnesium sulfate, zinc nitrate, aluminum nitrate, yttrium nitrate, calcium nitrate, chromium nitrate, nitric acid Cobalt, zirconium nitrate, bismuth nitrate, iron nitrate (II, III), copper nitrate, nickel nitrate, barium nitrate, magnesium nitrate, manganese nitrate, zinc hydroxide, aluminum hydroxide, yttrium hydroxide, calcium hydroxide, chromium hydroxide (II, III), cobalt hydroxide, zirconium hydroxide, iron hydroxide (II, III), copper hydroxide (I, II), nickel hydroxide, barium hydroxide, bismuth hydroxide, magnesium hydroxide, zinc acetate , Cobalt acetate, copper acetate, nickel acetate, iron acetate, active Examples include charcoal, graphite, carbon fiber, zeolite (aluminosilicate), calcium phosphate, and aluminum phosphate.
[0036]
(Supply to heating zone)
In order to continuously supply such an inorganic compound to the heating zone of the reactor, for example, a fine powder having an average particle size of 100 μm or less is dispersed in a solvent and sprayed into the reactor. In order to secure an effective area sufficient for adsorbing the catalyst particles, the particle diameter is preferably small. It is recommended that the average particle size is preferably 100 μm or less, more preferably 50 μm or less, still more preferably 30 μm or less, and most preferably 10 μm or less. Similarly, it is recommended that the maximum diameter be similarly small, 200 μm or less, more preferably 100 μm or less, still more preferably 50 μm or less, and most preferably 30 μm or less (the definition or measurement of this “average particle diameter”). For details of the method, reference can be made, for example, to literature: Chemical Engineering Handbook (P657, Maruzen, 4th edition, 1966)).
[0037]
An example of the most preferred additive component is activated carbon, graphite, silica, alumina, magnesia, titania, zirconia, zeolite, calcium phosphate, aluminum phosphate, which is easily available in powder form and preferably has an average particle size of 100 μm or less. , And a carbon fiber having an aspect ratio of 50 or less.
[0038]
(Additional components (2) and (3))
When the organic compound of the additive component (2) and the organic compound polymer of the additive component (3) are used, affinity with the catalyst precursor compound and the like can be an important factor for enhancing the effect. Therefore, organic compounds having heteroatoms such as oxygen, nitrogen, sulfur and phosphorus in addition to the above boiling point, decomposition temperature and molecular weight are often more effective than simple hydrocarbons. Further, when a hydrocarbon liquid at room temperature such as benzene or toluene is used as the carbon source of the carbon fiber, an organic compound that can be dissolved in such a hydrocarbon is preferable because supply is easy.
[0039]
Examples of organic compounds that can be used as additive component (2) and organic compound polymers of additive (3) include saturated and unsaturated hydrocarbons and higher alcohols and olefins having 10 or more carbon atoms; Ethylenes; dienes; acetylene derivatives, styrene derivatives, vinyl ester derivatives, vinyl ether derivatives, vinyl ketone derivatives, acrylic acid / methacrylic acid derivatives, acrylic acid ester derivatives, methacrylic acid ester derivatives, acrylamide / methacrylamide derivatives, acrylonitrile / methacrylonitrile Derivatives, maleic acid / maleimide derivatives, vinylamine derivatives, phenol derivatives, melamines / urea derivatives, amine derivatives, carboxylic acid / carboxylic acid ester derivatives, diol / polyol derivatives, isocyanate / isothiols Annatto derivatives, at least one organic compound selected from the group consisting of and a polymer thereof.
[0040]
More preferable compounds in terms of economy and versatility include octyl alcohol, decyl alcohol, cetyl alcohol, stearyl alcohol, oleic acid, stearic acid, adipic acid, linoleic acid, erucic acid, behenic acid, myristic acid, lauric acid, caprin. Acid, caprylic acid, hexanoic acid and their sodium and potassium salts; dimethyl malonate, dimethyl maleate, dibutyl phthalate, ethylhexyl phthalate, diisononyl phthalate, diisodecyl phthalate, diundecyl phthalate, ditridecyl phthalate, diphthalate diphthalate Butoxyethyl, ethylhexyl phthalate, ethylhexyl adipate, diisononyl adipate, diisodecyl adipate, dibutoxyethyl adipate, ethylhexyl trimellirate; Coal, polypropylene glycol, polyoxyethylene glycol monomethyl ether, polyoxyethylene glycol dimethyl ether, polyoxyethylene glycol glycerin ether, polyoxyethylene glycol lauryl ether, polyoxyethylene glycol tridecyl ether, polyoxyethylene glycol cetyl ether, polyoxyethylene Glycol stearyl ether, polyoxyethylene glycol oleyl ether, polypropylene glycol diallyl ether, polyoxyethylene glycol nonylphenyl ether, polyoxyethylene glycol octyl ether, polypropylene glycol stearate; sodium di-2-ethylhexyl sulfosuccinate, polyethylene oxide, polypropylene Oxide, polyacetal, polytetrahydrofuran, polyvinyl acetate, polyvinyl alcohol, polymethyl acrylate, polymethyl methacrylate, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyurethane, unsaturated polyester, epoxy resin, phenol resin, polycarbonate, Polyamide, polyphenylene oxide, polyacrylonitrile, polyvinyl pyrrolidone, etc. are mentioned.
[0041]
When an organic compound is used as an additive component, it itself is composed of carbon, so that it exists as a solid phase or a liquid phase in the early stage of the reaction to suppress aggregation of the catalyst particles, and at a later stage of the reaction or thereafter. In some cases, it can be expected to vaporize by heat treatment, decompose and volatilize, or be incorporated into the product as carbon fibers. The selection of such a compound is very advantageous because a fiber with few or substantially no impurities can be obtained without any special purification treatment. Although it is possible to suppress agglomeration of catalyst particles by using a catalyst having a metal supported on a carrier such as alumina, according to the method of the present invention, a catalyst having an appropriate particle size is generated in the reactor, Further, in addition to maintaining the state, there is also an effect of leaving no trace as a support, so that it is much more efficient and effective than the method using a conventional supported catalyst.
[0042]
(Addition amount of additive components)
The addition amount of the additive component is preferably 0.001 to 10,000, more preferably 0.01 to 1000, and most preferably 0.1 to 100 in terms of mass ratio to the metal in the catalyst. If the amount is less than 0.001, the amount of carbon fiber produced is decreased, and even if it is added more than 10,000, the effect is not increased, and conversely, the powdery product is increased, which is not preferable.
[0043]
In addition, it cannot be overemphasized that the carbon compound used as a carbon source and a catalyst precursor are not contained in the additional component said by this invention.
[0044]
The carbon compound, the catalyst precursor compound, and the additive component can be individually introduced into the reaction system, but are preferably mixed and dissolved to be simultaneously supplied to the reactor as a composition.
[0045]
(Carrier gas)
In the production of the vapor grown carbon fiber of the present invention, it is recommended to use a carrier gas in addition to these components or compositions. As the carrier gas, hydrogen, nitrogen, carbon dioxide, helium, argon, krypton, or a mixed gas thereof can be used. However, oxygen molecules such as air (that is, oxygen in the molecular state: O ₂ ) Is not suitable. The catalyst precursor compound used in the present invention may be in an oxidized state. In such a case, it is preferable to use a gas containing hydrogen as a carrier gas. Therefore, a preferable carrier gas is a gas containing 1 vol% or more, further 30 vol% or more, and most preferably 85 vol% or more of hydrogen, for example, a gas obtained by diluting 100 vol% hydrogen or hydrogen with nitrogen.
[0046]
(Sulfur compound)
Furthermore, a sulfur compound that is said to be effective in controlling the carbon fiber diameter may be used in combination. Compounds such as sulfur, thiophene, and hydrogen sulfide may be supplied in a gaseous state or dissolved in a solvent. Of course, the carbon compound, the catalyst precursor compound, and a substance containing sulfur in the additive may be used. The total number of moles of sulfur to be supplied is 1000 times or less, preferably 100 times or less, more preferably 10 times or less the number of moles of metal in the catalyst. If the amount of sulfur to be supplied is too large, it is not preferable because it is not economical, and it causes the growth of carbon fibers to be hindered.
[0047]
(Synthesis of carbon fiber)
The synthesis of the vapor grown carbon fiber is achieved by supplying the raw materials described so far and, if necessary, a carrier gas to the heating zone and bringing them into contact under heating. The reactor (heating furnace) is not particularly limited as long as a predetermined residence time and heating temperature can be obtained, but a vertical or horizontal tubular furnace is preferable in terms of raw material supply and residence time control. It is necessary not only to select the additive component but also to appropriately adjust the reaction conditions so that at least a part of the additive component exists as a solid or liquid. Such reaction conditions are not particularly limited as long as they can change the volatilization and decomposability of the additive component. In general, the temperature of the heating zone, the residence time, the supply concentration of the additive component, the supply method, etc. It is.
[0048]
The temperature in the heating zone varies greatly depending on the carbon compound used and the type of additive component, but generally it is preferably 500 ° C. or higher and 1500 ° C. or lower, more preferably 600 ° C. or higher and 1350 ° C. or lower. If the temperature is too low, the carbon fiber does not grow, and if it is too high, the additive component becomes a gas in the heating zone and the addition effect cannot be obtained, and the fiber does not grow or only a thick fiber is obtained.
[0049]
The residence time is adjusted by the length of the heating zone and the flow rate of the carrier gas. Although it varies greatly depending on the type of the reaction apparatus and the carbon compound used, it is generally within 0.001 second to 2 hours, more preferably 0.001 to 100 seconds, and most preferably 0.01 to 30 seconds. If the residence time is too short, the carbon fiber does not grow, and if it is too long, the additive component becomes a gas in the heating zone, and the addition effect cannot be obtained, or only a thick fiber can be obtained.
[0050]
The supply concentration of the additive component is adjusted by the flow rate of the carrier gas and the supply rate of the carbon compound. What is necessary is just to select suitably according to other conditions, such as the reaction apparatus to be used, an addition component, and the kind of carbon compound. Expressing the preferred concentration as the additive component mass in the carrier gas is preferably 0.0000001 to 100 g / NL, more preferably 0.000001 to 10 g / NL, and most preferably 0.00001 to 1 g / NL. Here, the volume of the carrier gas is expressed in terms of the standard state. If the supply concentration is too low, the additive component becomes gas in the heating zone, and the added effect tends to be difficult to obtain.
The method for supplying the additive component is not particularly limited as long as it is appropriately prepared so that at least a part of the additive component is present as a solid or liquid in the heating zone, depending on the reaction conditions such as the additive component to be used and the additive concentration. . Preferred examples of application include a method in which the additive component is supplied to the heating zone in a liquid state, a solution state or a liquid dispersed state, and the catalyst precursor compound and the additive component are dissolved in the same liquid which may be a carbon source. Alternatively, a method of dispersing and supplying to the heating zone, and a method of supplying the catalyst precursor compound in the gaseous state and dissolving or dispersing the additive component in the same liquid which may be a carbon supply source to supply to the heating zone are exemplified. It is done. The liquid component containing these additive components is preferably supplied using a spray nozzle installed in the reaction tube.
(Spray nozzle)
The shape of the spray nozzle is not particularly limited, but a multi-tube type, one-fluid type, two-fluid type, etc. structure can be used, and further, a liquid component and a gas component such as a carrier gas are mixed in the nozzle. Any structure of a mixing system or an external mixing system that mixes outside the nozzle can be used. In particular, as a multi-tube structure, a double-pipe structure (FIG. 5) and a triple-pipe structure (FIG. 6) as shown in FIGS. 5 and 6 are preferable.
The spray nozzle can be installed at any place such as the inlet of the reaction tube, the middle portion, or the like, and the discharge portion of the spray nozzle can be inserted into the reaction tube. In any case, in order to maintain at least a part of the additive component in a solid or liquid state in the heating zone, the tip temperature of the discharge nozzle, the liquid component containing the additive component, and the discharge speed of the gas component such as the carrier gas are adjusted. It is important to control.
The temperature at the tip of the discharge nozzle depends on the type of additive component used and the type of spray nozzle, but is preferably 200 ° C. or lower, more preferably 150 ° C. or lower, and most preferably 100 ° C. or lower. In order to maintain such temperature conditions, it is preferable to adjust the installation position of the spray nozzle or to provide a cooling mechanism for the spray nozzle. The cooling mechanism is not particularly limited as long as the temperature of the nozzle discharge portion can be maintained at a predetermined temperature. For example, a cooling jacket is installed outside the spray nozzle, and a medium such as water or various inert gases is placed in the jacket. It is preferable to cool by circulating. When the temperature of the nozzle discharge part exceeds 200 ° C., spherical carbon particles are mixed in the product, which is not preferable.
The blowing speed from the nozzle discharge unit can be easily obtained in the case of a single fluid nozzle, but is difficult to obtain in the case of a complicated structure such as a multi-tube nozzle. Even in such a case, the discharge speeds of the liquid component and the carrier gas component are very useful for predicting the spray state. For example, in the multi-tube nozzle as shown in FIGS. 5 and 6, each discharge speed is obtained by dividing the flow rate of the liquid component including the carrier gas and the additive component by the cross-sectional area of each flow path. . In particular, in the case of the internal mixing type nozzle as shown in FIG. 5, the liquid component is discharged along with the carrier gas, so the discharge speed of the liquid component is the same as the discharge speed of the carrier gas mixed internally. Estimated. In particular, in the case of an internal mixing type spray nozzle, it is preferable that any of the discharge speeds calculated in this way is 30 m / s or less. 10 m / s or less is optimal. When the discharge speed exceeds 30 m / s, the tendency of spherical carbon particles to be mixed into the product is not preferable.
[0051]
【Example】
EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated further in detail, this invention is not limited to these.
[0052]
The reagents used in the following examples and comparative examples are as follows.
[Reagents]
1. Carbon compound
Benzene: Special grade reagent manufactured by Wako Pure Chemical Industries, Ltd.
2. Catalyst precursor compound
Ferrocene: manufactured by Nippon Zeon Co., Ltd.
FeCl _Three : Reagents manufactured by Wako Pure Chemical Industries, Ltd.
CoCl ₂ : Reagents manufactured by Wako Pure Chemical Industries, Ltd.
3. Additive components
Polypropylene glycol: manufactured by NOF Corporation D-250 (molecular weight: 250, decomposition temperature 220 ° C.), D-400 (molecular weight: 400, decomposition temperature 290 ° C.)
AOT (sodium di-2-ethylhexylsulfosuccinate): DTP-100 (molecular weight: 444, decomposition temperature 290 ° C.) manufactured by Nikko Chemicals Co., Ltd.
Fumed silica: HS-5 manufactured by CABOT (molecular weight: 60, boiling point: 2230 ° C.)
Dibutyl phthalate: Wako Pure Chemical Industries, Ltd. (molecular weight: 278, boiling point: 339 ° C.)
Carbon fiber: VGCF-C manufactured by Showa Denko Co., Ltd., pulverized with a vibration mill and graphitized in argon at 2800 ° C., average fiber diameter 150 nm, average aspect ratio: 5
Activated carbon: Kuraray Co., Ltd. Kuraray Coal YP-17 (decomposition temperature 600 ° C or higher)
4). Other ingredients
Sulfur (powder): Reagent manufactured by Kanto Chemical Co., Inc.
[0053]
[Measurement of decomposition temperature]
The decomposition temperature of the additive component was heated to 600 ° C. with a differential thermal analyzer (Seiko Instruments DTA-TG SSC / 5200) at a nitrogen gas flow rate of 200 cc / min and a temperature increase rate of 10 ° C./min. At this time, the temperature when the weight loss of 50% by mass was read was taken as the decomposition temperature. When the weight reduction did not reach 50% by mass even after heating to 600 ° C., it was set to “600 ° C. or higher”.
[0054]
[Synthesis of carbon fiber]
<Examples 1-7>
In a vertical furnace provided with the quartz reaction tube 2 (inner diameter 31 mm, outer diameter 36 mm, heating zone length approximately 400 mm) shown in FIG. ₂ The temperature is raised to 1250 ° C. in an air stream, and then N ₂ Instead of supplying H, as a carrier gas at 1 NL / min in the reaction tube. ₂ Shed. After the temperature is stabilized, the reaction liquid shown in Table 1 (using benzene as a solvent or dispersion medium and carbon compound) is supplied from the raw material spray nozzle 1 for 10 minutes at a flow rate of 0.11 g / min using a small pump. did. The carrier gas was supplied at a rate of 0.3 NL / min and 0.7 NL / min to the outside and inside of the spray nozzle having the structure shown in FIG. The discharge speeds obtained from the cross-sectional area of the flow path of the spray nozzle were 3 m / S and 60 m / S, respectively. The temperature of the discharge part of the spray nozzle was 75 ° C. In addition, the preparation composition in a table | surface was described with the mass% in a benzene solution. The ethyl acetate of Example 2 is FeCl. _Three Was added to increase the solubility of benzene in benzene.
[0055]
As a result of the reaction, grayish spider web-like deposits were formed at the bottom of the reaction tube. After the temperature was lowered, this deposit was recovered, and the recovered amount was divided by the amount of benzene used to determine the carbon recovery rate. Further, the fibrous product was observed with a scanning electron microscope. The results are shown in Table 2 below. In each example, the components other than the additive component were replaced with water, the additive component was dissolved and dispersed in water, and sprayed into the reaction tube under the same conditions as in each example. Was recovered in a liquid or solid state.
[0056]
<Example 8>
Using the reaction apparatus shown in FIG. 3, polypropylene glycol (D-400): sulfur: benzene = 0.30: 0.03: 99.67% by mass of reaction liquid A was 0.11 g / min using a small pump. Then, the reaction liquid B of ferrocene: benzene = 3.33: 96.67% by mass is introduced into the vaporizer 7 heated to 200 ° C. at 0.003 g / min using a small pump. However, ferrocene and a small part of benzene were supplied as a gas accompanied by a carrier gas. Carrier gas (H ₂ ) The flow rate was 0.7 NL / min on the reaction solution A side and 0.3 NL / min on the reaction solution B side. The material spray nozzle 1 uses the triple pipe structure shown in FIG. 6, the carrier gas flow rates are 0.2 NL / min and 0.5 NL / min on the outside and inside, respectively, and the discharge speed is 2 m / s. 43 m / s. The temperature of the discharge part of the spray nozzle was 75 ° C. The same operation as in Examples 1 to 7 was performed except for the above conditions. The results are shown in Table 2 below.
[0057]
<Comparative Example 1>
The synthesis was performed in the same manner as in Example 1 except that the reaction solution shown in Table 1 was used.
[0058]
As a result, the reaction product was mostly spherical carbon powder, and the fibrous product was negligible.
[0059]
<Comparative example 2>
As a reactor, as shown in FIG. 4, an apparatus in which a vaporization heater 5 and a plate 6 are installed in the raw material introduction part of the reaction apparatus of FIG. 2 was used. The temperature of the vaporization heater 5 was set to 300 ° C., and after the reaction composition (reaction liquid) was completely vaporized, the same operation as in Example 4 was performed except that the vaporization heater 5 was introduced into the heating zone. The obtained reaction product was mostly spherical carbon powder, the recovery rate was 37%, and the fibrous product was negligible.
[0060]
<Example 9, Comparative Example 3>
The reaction was performed under the same conditions as in Example 1 except that the temperature of the discharge part of the spray nozzle was changed to the temperature shown in Table 1 by changing the insertion position of the raw material spray nozzle in the reaction tube shown in FIG. went.
<Examples 10 and 11, Comparative Example 4>
The double pipe type nozzle shown in FIG. 5 is used, the total carrier gas amount is constant at 1 NL / min, and the carrier gas is not passed through the outside and inside of the spray nozzle and through the nozzle so as to satisfy the conditions shown in Table 1. Directly fed to the reaction tube. The reaction was performed in the same manner as in Example 1 except for the conditions shown in Table 1.
[Table 1]

[0061]
[Table 2]

[0062]
【The invention's effect】
As described above, according to the present invention, pretreatment such as pre-supporting the catalyst is not essential, and specific additive components are supplied to the reaction system, and the conditions are adjusted so that aggregation and coarsening of the catalyst particles can be achieved. Compared to the loading method, it is possible to suppress the process, and not only is it possible to significantly shorten the process, it is economical, but also carbon fiber can be obtained in a high yield with a very small amount of catalyst, and carbon fiber is produced at low cost. It becomes possible.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing a general example of a horizontal reaction apparatus for producing vapor grown carbon fiber.
FIG. 2 is a schematic cross-sectional view showing a reaction apparatus for producing vapor grown carbon fiber in Examples 1 to 7, 9 to 11 and Comparative Examples 1, 3, and 4.
3 is a schematic cross-sectional view showing a reaction apparatus for producing vapor grown carbon fiber in Example 8. FIG.
4 is a schematic cross-sectional view showing a reaction apparatus for producing vapor grown carbon fiber having a heater in the raw material introduction part used in Comparative Example 2. FIG.
5 is a schematic cross-sectional view showing a double tube nozzle used in Examples 10 and 11 and Comparative Example 4. FIG.
6 is a schematic cross-sectional view showing a triple tube nozzle used in Examples 1 to 7, 9 and Comparative Examples 1 and 3. FIG.
[Explanation of symbols]
1 ... Raw material spray nozzle
2 ... Quartz reaction tube
3 ... Heater
4 ... Collector
5 ... Vaporizing heater
6 ... Plate
7 ... Vaporizer
8 ... Carrier gas (inside)
9 ... Reaction liquid
10 ... Carrier gas (outside)
11 ... Inner pipe
12 ... Outer pipe
13 ... Middle pipe

Claims (21)

A process for continuously producing carbon fibers in the gas phase by contacting a carbon compound with a catalyst and / or catalyst precursor compound in a heating zone;
This method supplies a carbon compound, a catalyst precursor compound and an additive component to a heating zone, and the additive component does not vaporize or decompose in the heating zone, and at least a part of the additive component exists as a solid or liquid. Characterized by reacting under conditions, and
The method for producing vapor grown carbon fiber in which the catalyst or the catalyst compound is supplied to the heating zone of the reactor in an independent state without being immobilized by chemical interaction with the additive component.   The method for producing a vapor grown carbon fiber according to claim 1, wherein the chemical interaction is adsorption, inclusion, and formation of a chemical bond between the catalyst or catalyst compound and the additive component.   The method for producing vapor grown carbon fiber according to claim 1 or 2, wherein the reaction conditions are at least one selected from the temperature of the heating zone, the residence time, the supply concentration of the additive component, and the supply method of the reaction raw material.   The method for producing vapor grown carbon fiber according to any one of claims 1 to 3, wherein the additive component is supplied to the heating zone in a liquid state, a solution state, or a state dispersed in a liquid.   The gas phase grown carbon fiber according to any one of claims 1 to 3, wherein the catalyst precursor compound and the additive component are dissolved or dispersed in the same liquid which may be a carbon supply source and supplied to the heating zone. Production method.   The gas phase method according to any one of claims 1 to 3, wherein the catalyst precursor compound is in a gaseous state and the additive component is dissolved or dispersed in the same liquid which may be a carbon supply source and supplied to the heating zone. A method for producing carbon fiber.   The method for producing vapor grown carbon fiber according to any one of claims 4 to 6, wherein a liquid component containing an additive component is supplied using a spray nozzle installed in a reaction tube.   The method for producing vapor grown carbon fiber according to claim 7, wherein the temperature of the discharge part of the spray nozzle is 200 ° C. or less.   The method for producing vapor-grown carbon fiber according to claim 7, wherein a discharge speed of a liquid component including an additive component and a gas component such as a carrier gas is 30 m / min or less in a discharge portion of a spray nozzle.   The method for producing vapor grown carbon fiber according to any one of claims 1 to 9, wherein the additive component is an organic compound or an organic compound polymer. The method for producing vapor grown carbon fiber according to any one of claims 1 to 9, wherein the additive component is at least one compound selected from the group consisting of the following additive component (1) to additive component (3).
Additive component (1): Inorganic compound whose boiling point or decomposition temperature is lower is 180 ° C. or higher Additive component (2): Organic compound whose boiling point or decomposition temperature is lower is 180 ° C. or higher Additive component (3 ): Organic compound polymer having a molecular weight of 200 or more   The process for producing vapor grown carbon fiber according to claim 11, wherein the additive component (1) is an inorganic compound containing at least one element selected from the group consisting of Group 2 to 15 elements in the Group 18 element periodic table. Method.   The additive component (1) is made of Mg, Ca, Sr, Ba, Y, La, Ti, Zr, Cr, Mo, W, Fe, Co, Ni, Cu, Zn, B, Al, C, Si, Bi The method for producing vapor grown carbon fiber according to claim 11, which is an inorganic compound containing at least one element selected from the group consisting of:   Additive component (1) is powdered activated carbon, graphite, silica, alumina, magnesia, titania, zirconia, zeolite, calcium phosphate, aluminum phosphate, or carbon fiber having an aspect ratio of 1 to 50 and an average fiber diameter of 10 to 300 nm The method for producing vapor grown carbon fiber according to claim 11, which is at least one selected from the group consisting of:   The method for producing vapor grown carbon fiber according to claim 11, wherein the additive component (2) is an organic compound containing at least one element selected from the group consisting of oxygen, nitrogen, sulfur and phosphorus.   Additive component (2) is halogenated ethylenes, dienes, acetylene derivatives, styrene derivatives, vinyl ester derivatives, vinyl ether derivatives, vinyl ketone derivatives, acrylic acid derivatives, methacrylic acid derivatives, acrylic acid ester derivatives, methacrylic acid ester derivatives, acrylamide derivatives , Methacrylamide derivatives, acrylonitrile derivatives, methacrylonitrile derivatives, maleic acid derivatives, maleimide derivatives, vinylamine derivatives, phenol derivatives, melamines, urea derivatives, amine derivatives, carboxylic acid derivatives, carboxylic acid ester derivatives, diol derivatives, polyol derivatives, The method for producing vapor-grown carbon fiber according to claim 11, which is at least one organic compound selected from the group consisting of an isocyanate derivative and an isothiocyanate derivative.   The method for producing vapor grown carbon fiber according to claim 11, wherein the additive component (3) is an organic compound polymer containing at least one element selected from the group consisting of oxygen, nitrogen, sulfur and phosphorus.   Additive component (3) is olefins, halogenated ethylenes, dienes, acetylene derivatives, styrene derivatives, vinyl ester derivatives, vinyl ether derivatives, vinyl ketone derivatives, acrylic acid derivatives, methacrylic acid derivatives, acrylic acid ester derivatives, methacrylic acid ester derivatives , Acrylamide derivatives, methacrylamide derivatives, acrylonitrile derivatives, methacrylonitrile derivatives, maleic acid derivatives, maleimide derivatives, vinylamine derivatives, phenol derivatives, melamines / urea derivatives, amine derivatives, carboxylic acid derivatives, carboxylic acid ester derivatives, diol derivatives, 12. The gas according to claim 11, which is a polymer of at least one organic compound selected from the group consisting of a polyol derivative, an isocyanate derivative, and an isothiocyanate derivative. Method of manufacturing a law carbon fiber.   The method for producing vapor grown carbon fiber according to claim 1, wherein the catalyst precursor compound is a compound that can become a gas in the heating zone.   The method for producing vapor-grown carbon fiber according to claim 1, wherein the catalyst precursor compound contains at least one metal selected from Group 3, 5, 6, 8, 9, and 10 in the group 18 element periodic table. .   21. The method for producing vapor-grown carbon fiber according to claim 20, wherein the mass ratio of the additive component to the metal atom in the catalyst precursor compound (additive component / metal atom in the catalyst precursor compound) is 0.001 to 10,000. .

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