JP2009062646A - Method for producing vapor growth carbon fiber, and vapor growth carbon fiber - Google Patents
Method for producing vapor growth carbon fiber, and vapor growth carbon fiber Download PDFInfo
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- 238000004519 manufacturing process Methods 0.000 title claims abstract description 39
- 229920000049 Carbon (fiber) Polymers 0.000 title abstract description 33
- 239000004917 carbon fiber Substances 0.000 title abstract description 33
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 title description 31
- 239000003054 catalyst Substances 0.000 claims abstract description 63
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 claims abstract description 56
- 238000000034 method Methods 0.000 claims abstract description 25
- 239000000835 fiber Substances 0.000 claims abstract description 21
- 229910052751 metal Inorganic materials 0.000 claims abstract description 18
- 239000002184 metal Substances 0.000 claims abstract description 18
- 235000006408 oxalic acid Nutrition 0.000 claims abstract description 17
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 10
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 9
- 238000001035 drying Methods 0.000 claims abstract description 7
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 23
- 239000002134 carbon nanofiber Substances 0.000 claims description 22
- 239000011777 magnesium Substances 0.000 claims description 12
- 239000002245 particle Substances 0.000 claims description 11
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims description 9
- 229910052742 iron Inorganic materials 0.000 claims description 9
- 229910052750 molybdenum Inorganic materials 0.000 claims description 9
- 239000011733 molybdenum Substances 0.000 claims description 9
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 7
- APUPEJJSWDHEBO-UHFFFAOYSA-P ammonium molybdate Chemical compound [NH4+].[NH4+].[O-][Mo]([O-])(=O)=O APUPEJJSWDHEBO-UHFFFAOYSA-P 0.000 claims description 7
- 239000011609 ammonium molybdate Substances 0.000 claims description 7
- 229940010552 ammonium molybdate Drugs 0.000 claims description 7
- 235000018660 ammonium molybdate Nutrition 0.000 claims description 7
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 6
- 229910052749 magnesium Inorganic materials 0.000 claims description 6
- 150000001875 compounds Chemical class 0.000 claims description 5
- 150000002823 nitrates Chemical class 0.000 claims description 5
- 150000001242 acetic acid derivatives Chemical class 0.000 claims description 4
- 238000001354 calcination Methods 0.000 claims description 4
- 150000001805 chlorine compounds Chemical class 0.000 claims description 4
- 229910052759 nickel Inorganic materials 0.000 claims description 4
- 150000003467 sulfuric acid derivatives Chemical class 0.000 claims description 4
- 229910017052 cobalt Inorganic materials 0.000 claims description 3
- 239000010941 cobalt Substances 0.000 claims description 3
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 3
- 238000002156 mixing Methods 0.000 claims description 3
- 239000000203 mixture Substances 0.000 claims description 3
- ZKKLPDLKUGTPME-UHFFFAOYSA-N diazanium;bis(sulfanylidene)molybdenum;sulfanide Chemical compound [NH4+].[NH4+].[SH-].[SH-].S=[Mo]=S ZKKLPDLKUGTPME-UHFFFAOYSA-N 0.000 claims description 2
- CWQXQMHSOZUFJS-UHFFFAOYSA-N molybdenum disulfide Chemical compound S=[Mo]=S CWQXQMHSOZUFJS-UHFFFAOYSA-N 0.000 claims description 2
- VLAPMBHFAWRUQP-UHFFFAOYSA-L molybdic acid Chemical compound O[Mo](O)(=O)=O VLAPMBHFAWRUQP-UHFFFAOYSA-L 0.000 claims description 2
- 238000009826 distribution Methods 0.000 abstract description 6
- 238000007796 conventional method Methods 0.000 abstract description 3
- 239000003426 co-catalyst Substances 0.000 abstract description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 28
- 239000000243 solution Substances 0.000 description 16
- 239000007789 gas Substances 0.000 description 10
- 238000006243 chemical reaction Methods 0.000 description 8
- 238000001947 vapour-phase growth Methods 0.000 description 7
- YIXJRHPUWRPCBB-UHFFFAOYSA-N magnesium nitrate Chemical compound [Mg+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O YIXJRHPUWRPCBB-UHFFFAOYSA-N 0.000 description 6
- 150000002736 metal compounds Chemical class 0.000 description 6
- 239000002243 precursor Substances 0.000 description 6
- 238000002360 preparation method Methods 0.000 description 6
- 230000000052 comparative effect Effects 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 238000005470 impregnation Methods 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- MVFCKEFYUDZOCX-UHFFFAOYSA-N iron(2+);dinitrate Chemical compound [Fe+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O MVFCKEFYUDZOCX-UHFFFAOYSA-N 0.000 description 4
- 229910044991 metal oxide Inorganic materials 0.000 description 4
- 150000004706 metal oxides Chemical class 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 3
- 238000010304 firing Methods 0.000 description 3
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 2
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 2
- KDLHZDBZIXYQEI-UHFFFAOYSA-N Palladium Chemical compound [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 229910002091 carbon monoxide Inorganic materials 0.000 description 2
- 238000005119 centrifugation Methods 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 238000000975 co-precipitation Methods 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000000395 magnesium oxide Substances 0.000 description 2
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 2
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 230000001376 precipitating effect Effects 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 239000006228 supernatant Substances 0.000 description 2
- 238000004438 BET method Methods 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 238000001241 arc-discharge method Methods 0.000 description 1
- 229910021393 carbon nanotube Inorganic materials 0.000 description 1
- 239000002041 carbon nanotube Substances 0.000 description 1
- 238000001628 carbon nanotube synthesis method Methods 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 150000007942 carboxylates Chemical class 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 125000002534 ethynyl group Chemical group [H]C#C* 0.000 description 1
- KTWOOEGAPBSYNW-UHFFFAOYSA-N ferrocene Chemical compound [Fe+2].C=1C=C[CH-]C=1.C=1C=C[CH-]C=1 KTWOOEGAPBSYNW-UHFFFAOYSA-N 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 238000007429 general method Methods 0.000 description 1
- 150000002681 magnesium compounds Chemical class 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000011572 manganese Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 125000000896 monocarboxylic acid group Chemical group 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000002203 pretreatment Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 238000006722 reduction reaction Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
- 238000007740 vapor deposition Methods 0.000 description 1
- 239000012808 vapor phase Substances 0.000 description 1
- 229910052727 yttrium Inorganic materials 0.000 description 1
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 1
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- Carbon And Carbon Compounds (AREA)
- Catalysts (AREA)
- Inorganic Fibers (AREA)
Abstract
Description
本発明は、気相成長炭素繊維の製造方法（以下、単に「製造方法」とも称する）および気相成長炭素繊維に関し、詳しくは、使用する触媒の改良に係る気相成長炭素繊維の製造方法および気相成長炭素繊維に関する。 The present invention relates to a method for producing a vapor-grown carbon fiber (hereinafter, also simply referred to as “manufacturing method”) and a vapor-grown carbon fiber, and more specifically, a method for producing a vapor-grown carbon fiber according to improvement of a catalyst used and It relates to vapor grown carbon fiber.
気相成長炭素繊維は、カーボンナノチューブ、カーボンナノファイバーとも呼ばれる直径がナノメートルオーダーの繊維状の炭素材料である。かかる気相成長炭素繊維は、炭化水素や一酸化炭素等の炭素を含むガスを原料とし、これら原料ガスを５００〜１５００℃程の高温下で触媒に接触させて熱分解させる気相成長法により製造され、触媒として使用する金属の種類や粒径等を選択することで、得られる繊維の形状を制御できることが知られている。 Vapor growth carbon fiber is a fibrous carbon material having a diameter of nanometer order called carbon nanotube or carbon nanofiber. Such vapor-grown carbon fibers are obtained by vapor-phase growth method in which a gas containing carbon such as hydrocarbon or carbon monoxide is used as a raw material, and these raw material gases are contacted with a catalyst at a high temperature of about 500 to 1500 ° C. and thermally decomposed. It is known that the shape of the resulting fiber can be controlled by selecting the type, particle size, etc. of the metal that is produced and used as the catalyst.
気相成長法で用いられる触媒は、例えば、溶液中で触媒金属と担体とを共沈させる共沈法により調製できることが知られている。例えば、特許文献１には、金属化合物、およびアルミニウムおよび／またはマグネシウム化合物からなる水溶液を形成し、カルボキシレート存在下でこれらを共沈させ、共沈物を処理して担持された原繊維形成触媒を製造する炭素原繊維形成触媒の製造方法が開示されており、前記金属としては、鉄若しくは鉄およびモリブデンが使用できることが開示されている。 It is known that the catalyst used in the vapor phase growth method can be prepared, for example, by a coprecipitation method in which a catalytic metal and a carrier are coprecipitated in a solution. For example, Patent Document 1 discloses a fibril-forming catalyst supported by forming an aqueous solution comprising a metal compound and an aluminum and / or magnesium compound, coprecipitating them in the presence of a carboxylate, and treating the coprecipitate. Is disclosed, and it is disclosed that iron or iron and molybdenum can be used as the metal.
また、特許文献２には、少なくとも水溶性VIII族金属化合物と、有機化合物とを含む混合物を焼成してなり、VIII族金属酸化物における非晶質VIII族金属酸化物が１０質量％以上で、且つ全金属酸化物における結晶質金属酸化物が８５質量％以下である気相成長法炭素繊維製造用触媒が開示されている。 Patent Document 2 discloses that a mixture containing at least a water-soluble group VIII metal compound and an organic compound is baked, and the amorphous group VIII metal oxide in the group VIII metal oxide is 10% by mass or more. In addition, a catalyst for producing a carbon fiber by vapor phase growth method in which the crystalline metal oxide in the total metal oxide is 85% by mass or less is disclosed.
さらに、従来の気相成長法では、安価な触媒を使用する際に、活性金属種（Ｆｅ、Ｎｉ、Ｃｏ等）を微粒子状に保つために触媒調製時に様々な前処理を施している。一般には、気相成長炭素繊維は、触媒溶液調整後、乾燥、焼成、還元前処理により得られた触媒と、炭素を含むガスとの反応工程を経て得られている。
カーボンナノチューブの合成法には、気相成長法以外にアーク放電法やレーザー蒸着法が存在するが、いずれもコストが高いという問題点があった。また、気相成長法においても、触媒に高価なフェロセン等を用いることが多いため、生産コストが高くなるという問題があった。さらに、低コストで一般的な触媒調製手法として含浸法が存在するが、含浸法で得られる触媒は表面積が狭いため、収率がよくないという難点があり、得られる気相成長炭素繊維も直径が太く、繊維径の分布も広くなってしまう。さらにまた、触媒の製造工程が多いため、生産コストが高くなるという問題があった。したがって、繊維径が細く繊維径の分布の狭い気相成長炭素繊維を、収率よく得るための技術の確立が求められていた。 The carbon nanotube synthesis methods include an arc discharge method and a laser vapor deposition method in addition to the vapor phase growth method, all of which have a problem of high cost. Also, in the vapor phase growth method, since expensive ferrocene or the like is often used for the catalyst, there is a problem that the production cost is increased. Furthermore, there is an impregnation method as a general catalyst preparation method at a low cost, but the catalyst obtained by the impregnation method has a problem that the yield is not good because the surface area is narrow, and the obtained vapor-grown carbon fiber also has a diameter. Is thick and the fiber diameter distribution becomes wide. Furthermore, since there are many manufacturing processes of a catalyst, there existed a problem that production cost became high. Therefore, establishment of a technique for obtaining a vapor-grown carbon fiber having a narrow fiber diameter and a narrow fiber diameter distribution in a high yield has been demanded.
そこで、本発明の目的は、繊維径が細く繊維径の分布の狭い気相成長炭素繊維を、従来に比し高収率で得ることができ、低コストである気相成長炭素繊維の製造方法および気相成長炭素繊維を提供することにある。 Accordingly, an object of the present invention is to provide a vapor-grown carbon fiber having a narrow fiber diameter and a narrow fiber diameter distribution, which can be obtained at a higher yield than conventional methods, and is low in cost. And providing vapor grown carbon fibers.
本発明者は、前記課題を解決するために鋭意検討した結果、気相成長法で用いる触媒を共沈法を用いて調製するにあたり、沈殿剤としてシュウ酸を用い、触媒の製造過程で焼成工程および還元前処理工程を経ないことで、却って、比較的高い収率で繊維径が細く繊維径の分布の狭い炭素繊維を得ることが可能となることを見出して、本発明を完成するに至った。 As a result of diligent studies to solve the above problems, the present inventor used oxalic acid as a precipitating agent to prepare a catalyst used in a vapor phase growth method using a coprecipitation method, and a calcination step in the catalyst production process. On the other hand, by not conducting the reduction pretreatment step, it was found that carbon fibers with a relatively high yield and a narrow fiber diameter and a narrow fiber diameter distribution can be obtained, and the present invention has been completed. It was.
すなわち、本発明は、炭素を含むガスを触媒と接触させて気相成長炭素繊維を製造する方法において、前記触媒として、担体、活性金属種および助触媒とを、シュウ酸を用いて共沈させた後に、焼成工程および還元前処理工程を経ることなく、乾燥させて得られるものを用いることを特徴とするものである。 That is, the present invention provides a method for producing a vapor-grown carbon fiber by bringing a gas containing carbon into contact with a catalyst, and co-precipitating a support, an active metal species and a co-catalyst using oxalic acid as the catalyst. After that, what is obtained by drying without passing through the firing step and the pre-reduction treatment step is used.
また、本発明の気相成長炭素繊維は、上記本発明の製造方法により製造され、繊維径が５〜５０ｎｍであることを特徴とするものである。 The vapor grown carbon fiber of the present invention is produced by the production method of the present invention, and has a fiber diameter of 5 to 50 nm.
本発明によると、繊維径が細く繊維径の分布の狭い気相成長炭素繊維を、従来に比し高収率で得ることができ、低コストである気相成長炭素繊維の製造方法および気相成長炭素繊維を提供することができる。 According to the present invention, a vapor-grown carbon fiber having a narrow fiber diameter and a narrow fiber diameter distribution can be obtained in a higher yield than conventional methods, and a method for producing a vapor-grown carbon fiber and a vapor phase that are low in cost. Growing carbon fibers can be provided.
以下に本発明の実施の形態について具体的に説明する。
本発明の気相成長炭素繊維の製造方法は、炭素を含むガスを触媒と接触させて気相成長炭素繊維を製造する方法において、触媒として、担体、活性金属種および助触媒とを、シュウ酸を用いて共沈させた後に、焼成工程および還元前処理工程を経ることなく、乾燥させて得られるものを用いるものである。具体的には、沈殿剤としてシュウ酸を用い、触媒の製造過程で焼成工程および還元前処理工程を経ないで、乾燥させることにより得られるものを触媒として使用している。
Embodiments of the present invention will be specifically described below.
The method for producing a vapor-grown carbon fiber of the present invention is a method for producing a vapor-grown carbon fiber by bringing a gas containing carbon into contact with a catalyst. In the method for producing a vapor-grown carbon fiber, a carrier, an active metal species and a promoter are used as a catalyst. After being co-precipitated using, a product obtained by drying without using a firing step and a pre-reduction treatment step is used. Specifically, oxalic acid is used as a precipitating agent, and a catalyst obtained by drying without using a calcination step and a reduction pretreatment step in the production process of the catalyst is used as the catalyst.
また、本発明の製造方法において、担体、活性金属種および助触媒とを、シュウ酸を用いて共沈させた後に、焼成工程および還元前処理工程を経ないで、乾燥させて得られる触媒が、シュウ酸塩であることが好ましい。 In the production method of the present invention, a catalyst obtained by co-precipitating a support, an active metal species, and a cocatalyst using oxalic acid and then drying without passing through a calcination step and a reduction pretreatment step is provided. An oxalate is preferred.
本発明の製造方法において、活性金属種として鉄、ニッケル、コバルト、パラジウム等を用いることが好ましく、鉄、ニッケルまたはコバルトを用いることがさらに好ましい。 In the production method of the present invention, iron, nickel, cobalt, palladium or the like is preferably used as the active metal species, and iron, nickel or cobalt is more preferably used.
また、かかる活性金属種が、硝酸塩、酢酸塩、硫酸塩および塩化物塩から選ばれる少なくとも１種の化合物の形態であることが好ましく、硝酸塩であることがさらに好ましい。 The active metal species is preferably in the form of at least one compound selected from nitrates, acetates, sulfates and chlorides, and more preferably nitrates.
また、担体としては、マグネシウム、アルミニウム、シリカ、マンガン等を用いることが好ましく、マグネシウムを用いることがさらに好ましい。 As the carrier, magnesium, aluminum, silica, manganese or the like is preferably used, and magnesium is more preferably used.
さらに、かかる担体が、硝酸塩、酢酸塩、硫酸塩および塩化物塩から選ばれる少なくとも１種の化合物の形態であることが好ましく、硝酸マグネシウムであることがさらに好ましい。 Furthermore, the carrier is preferably in the form of at least one compound selected from nitrates, acetates, sulfates and chlorides, more preferably magnesium nitrate.
また、助触媒としては、モリブデン、イットリウム、タングステン等を用いることが好ましく、モリブデンを用いることがさらに好ましい。 As the cocatalyst, molybdenum, yttrium, tungsten, or the like is preferably used, and molybdenum is more preferably used.
さらに、かかる助触媒が、モリブデン酸、モリブデン酸アンモニウム、硫化モリブデン、モリブデンヘキサカルボニルまたはチオモリブデン酸アンモニウム等であることが好ましく、モリブデン酸アンモニウムであることがさらに好ましい。 Furthermore, the promoter is preferably molybdic acid, ammonium molybdate, molybdenum sulfide, molybdenum hexacarbonyl or ammonium thiomolybdate, and more preferably ammonium molybdate.
本発明の製造方法において、活性金属種と、担体および助触媒の合計との配合比率は、５：９５〜５０：５０であることが好ましく、７：９３〜３０：７０であることがさらに好ましい。この配合比率が５：９５より小さいと十分な触媒性能が得られず炭素繊維の収率が悪くなる場合があり、５０：５０より大きいと均一な繊維径の炭素繊維とならず、好ましくない。 In the production method of the present invention, the blending ratio of the active metal species and the total of the support and the cocatalyst is preferably 5:95 to 50:50, more preferably 7:93 to 30:70. . If this blending ratio is less than 5:95, sufficient catalyst performance may not be obtained, and the yield of carbon fibers may be deteriorated. If it is greater than 50:50, carbon fibers having a uniform fiber diameter are not preferred.
本発明の製造方法において、シュウ酸のモル数が、活性金属種、担体および助触媒の合計モル数に対して、０．８〜２．０倍量であることが好ましく、１．０〜１．５倍量であることがさらに好ましい。このシュウ酸のモル数が０．８倍量より小さいと触媒が共沈しない場合があり、２．０倍量より大きいと微細で均一な触媒が得られない場合があり、好ましくない。 In the production method of the present invention, the number of moles of oxalic acid is preferably 0.8 to 2.0 times the total number of moles of active metal species, support and cocatalyst, 1.0 to 1 More preferably, the amount is 5 times. If the number of moles of oxalic acid is less than 0.8 times, the catalyst may not coprecipitate, and if it is more than 2.0 times, a fine and uniform catalyst may not be obtained.
また、本発明における触媒としては、好ましくは、鉄とモリブデンとマグネシウムとを含むものであり、特に好ましくはＦｅＭｏＭｇ（ＣＯＯＨ）２等のシュウ酸塩である。 The catalyst in the present invention preferably contains iron, molybdenum and magnesium, and particularly preferably an oxalate such as FeMoMg (COOH) 2 .
さらに、本発明の製造方法において、触媒は、１０〜２００ｎｍの粒径で、かつ１５０〜１０００ｍ２／ｇの表面積であることが好ましく、３０〜１５０ｎｍの粒径で、かつ２００〜３００ｍ２／ｇの表面積であることがさらに好ましい。粒径が１０ｎｍより小さいと作業性が悪化する場合があり、２００ｎｍより大きいと触媒の効果が得られず炭素繊維の収率が悪くなる場合があり、好ましくない。また、表面積が１５０ｍ２／ｇより小さいと触媒の効果が得られず炭素繊維の収率が悪くなる場合があり、１０００ｍ２／ｇより大きいと作業性が悪化する場合があり、好ましくない。 Further, in the manufacturing method of the present invention, the catalyst is preferably in the particle size of 10 to 200 nm, and a surface area of 150~1000m 2 / g, with particle sizes of 30 to 150 nm, and 200 to 300 m 2 / g More preferably, the surface area is as follows. When the particle size is smaller than 10 nm, workability may be deteriorated. When the particle size is larger than 200 nm, the effect of the catalyst cannot be obtained and the yield of the carbon fiber may be deteriorated. On the other hand, if the surface area is less than 150 m 2 / g, the effect of the catalyst cannot be obtained and the yield of the carbon fiber may be deteriorated, and if it is greater than 1000 m 2 / g, the workability may be deteriorated.
さらにまた、本発明の製造方法において、ガスと触媒の接触は、７００〜９００℃で０．２５〜２時間であることが好ましく、８００〜９００℃で０．５〜１．５時間であることがさらに好ましい。接触温度が７００℃より低いと触媒の効果が不十分で良好な炭素繊維を得ることができない場合があり、９００℃より高いとメタンが熱分解して触媒と接触する前に炭素となる場合があり、好ましくない。また、接触時間が０．２５時間より短いと触媒の効果が不十分で良好な炭素繊維を得ることができない場合があり、２時間より長いと触媒が失活し活性を示さず反応が進行しない場合があり、好ましくない。 Furthermore, in the production method of the present invention, the contact between the gas and the catalyst is preferably 700 to 900 ° C. for 0.25 to 2 hours, and 800 to 900 ° C. for 0.5 to 1.5 hours. Is more preferable. If the contact temperature is lower than 700 ° C, the effect of the catalyst may be insufficient and good carbon fibers may not be obtained. If the contact temperature is higher than 900 ° C, methane may be pyrolyzed to become carbon before contacting the catalyst. Yes, not preferred. Further, if the contact time is shorter than 0.25 hours, the effect of the catalyst may be insufficient and a good carbon fiber may not be obtained. If the contact time is longer than 2 hours, the catalyst is deactivated and does not exhibit activity and the reaction does not proceed. In some cases, it is not preferable.
本発明の製造方法において、ガスとしては炭素を含むガスであれば特に限定されず、例えば、メタン、エチレン、アセチレン等の炭化水素や、一酸化炭素、アルコール等が挙げられ、好ましくは、窒素／メタンとの混合ガスである。また、ガスの組成がＮ２／ＣＨ４＝１／１〜１／１０であり、この流量が触媒０．５ｇあたり１５０ｍＬ／ｍｉｎ〜１０００ｍＬ／ｍｉｎであることが、好ましい。 In the production method of the present invention, the gas is not particularly limited as long as it contains carbon, and examples thereof include hydrocarbons such as methane, ethylene, and acetylene, carbon monoxide, alcohols, and the like. It is a mixed gas with methane. The gas composition is preferably N 2 / CH 4 = 1/1 to 1/10, and the flow rate is preferably 150 mL / min to 1000 mL / min per 0.5 g of the catalyst.
また、本発明の気相成長炭素繊維は、上記本発明の製造方法により製造され、繊維径が５〜５０ｎｍである。繊維径が５ｎｍより小さく合成することは物理的に難しく、５０ｎｍより大きいと炭素繊維の導電性等の物性が悪くなり、好ましくない。 Moreover, the vapor growth carbon fiber of this invention is manufactured by the manufacturing method of the said invention, and a fiber diameter is 5-50 nm. It is physically difficult to synthesize the fiber diameter smaller than 5 nm, and when it is larger than 50 nm, the physical properties such as the conductivity of the carbon fiber deteriorate, which is not preferable.
次に、本発明を実施例により更に詳しく説明する。本発明は、この例によって限定されるものではない。 Next, the present invention will be described in more detail with reference to examples. The present invention is not limited by this example.
実施例１
触媒の調製
硝酸鉄（関東化学株式会社製）、硝酸マグネシウム（関東化学株式会社製）およびモリブデン酸アンモニウム（関東化学株式会社製）を、重量比で（Ｆｅ：Ｍｏ：Ｍｇ＝１０：７：８３）の割合で秤量し、それぞれの前駆体のモル数に対して１ｍｏｌ／Ｌになるように９０％エタノールに溶解して、活性金属化合物溶液を調製した。Ｆｅ＋Ｍｏ＋Ｍｇの合計モル数に対して１．２倍量のシュウ酸を１ｍｏｌ／Ｌになるように９０％エタノールに溶解して、シュウ酸溶液を調製した。活性金属化合物溶液とシュウ酸溶液を混合し、鉄、マグネシウムおよびモリブデンをシュウ酸により同時に沈殿させた。遠心分離（２０００ｒｐｍ、１５分間）した後、上澄み液を廃棄して、９０％エタノールを加えて沈殿溶液を８０℃で４時間真空乾燥し、触媒を作製し、塊状のシュウ酸塩を得た。
Example 1
Preparation of catalyst Iron nitrate (manufactured by Kanto Chemical Co., Inc.), magnesium nitrate (manufactured by Kanto Chemical Co., Ltd.) and ammonium molybdate (manufactured by Kanto Chemical Co., Ltd.) are in a weight ratio (Fe: Mo: Mg = 10: 7: 83). ) And was dissolved in 90% ethanol so as to be 1 mol / L with respect to the number of moles of each precursor to prepare an active metal compound solution. An oxalic acid solution was prepared by dissolving oxalic acid in an amount of 1.2 times the total number of moles of Fe + Mo + Mg in 90% ethanol to 1 mol / L. The active metal compound solution and the oxalic acid solution were mixed, and iron, magnesium and molybdenum were simultaneously precipitated with oxalic acid. After centrifugation (2000 rpm, 15 minutes), the supernatant was discarded, 90% ethanol was added, and the precipitated solution was vacuum-dried at 80 ° C. for 4 hours to produce a catalyst to obtain massive oxalate.
粒径測定
粒径は、株式会社日立ハイテクノロジーズ社製のＳＥＭ Ｓ−５０００を用いて、ＳＥＭ観察で測定した。
Particle size measurement The particle size was measured by SEM observation using SEM S-5000 manufactured by Hitachi High-Technologies Corporation.
ＢＥＴ表面積測定
ＢＥＴ表面積は、ユアサアイオニクス株式会社製のＡｕｔｏＳｏｒｂ−１により測定した。
BET surface area measurement The BET surface area was measured by AutoSorb-1 manufactured by Yuasa Ionics.
反応工程
得られた触媒を８００℃まで昇温し、水素をメタンに切り替え、窒素／メタン＝１５０ｍＬ／１５０ｍＬ／ｍｉｎで３０分間反応させた。反応後、生成した炭素繊維を取り出し、重さを秤量し、収量を算出した。収量は生成した炭素繊維から予め仕込んだ触媒の重量を引き、触媒中に含まれる活性金属の量で割ることにより触媒１ｇ当りの炭素繊維生成量として計算した。この炭素繊維は、繊維径１０〜３０ｎｍであった。また、収量の結果を表１に示し、得られた炭素繊維を図１に示す。
Reaction process The obtained catalyst was heated up to 800 degreeC, hydrogen was switched to methane, and it was made to react by nitrogen / methane = 150mL / 150mL / min for 30 minutes. After the reaction, the produced carbon fiber was taken out, weighed, and the yield was calculated. The yield was calculated as the amount of carbon fiber produced per gram of catalyst by subtracting the weight of the catalyst charged in advance from the produced carbon fiber and dividing by the amount of active metal contained in the catalyst. This carbon fiber had a fiber diameter of 10 to 30 nm. The yield results are shown in Table 1, and the obtained carbon fibers are shown in FIG.
比較例１
触媒の調製
硝酸鉄（関東化学株式会社製）、硝酸マグネシウム（関東化学株式会社製）およびモリブデン酸アンモニウム（関東化学株式会社製）を、重量比で（Ｆｅ：Ｍｏ：Ｍｇ＝１０：７：８３）の割合で秤量し、それぞれの前駆体のモル数に対して１ｍｏｌ／Ｌになるように９０％エタノールに溶解して、活性金属化合物溶液を調製した。Ｆｅ＋Ｍｏ＋Ｍｇの合計モル数に対して１．２倍量のシュウ酸を１ｍｏｌ／Ｌになるように９０％エタノールに溶解して、シュウ酸溶液を調製した。活性金属化合物溶液とシュウ酸溶液を混合し、鉄、マグネシウムおよびモリブデンをシュウ酸により同時に沈殿させた。遠心分離（２０００ｒｐｍ、１５分間）した後、上澄み液を廃棄して、９０％エタノールを加えて沈殿溶液を８０℃で４時間真空乾燥し、前駆体を作製した。得られた前駆体を５５０℃で４時間焼成して触媒とした。この触媒は、粒径１００〜１５０ｎｍでＢＥＴ表面積が２５０ｍ２／ｇであった。
Comparative Example 1
Preparation of catalyst Iron nitrate (manufactured by Kanto Chemical Co., Inc.), magnesium nitrate (manufactured by Kanto Chemical Co., Ltd.) and ammonium molybdate (manufactured by Kanto Chemical Co., Ltd.) are in a weight ratio (Fe: Mo: Mg = 10: 7: 83). ) And was dissolved in 90% ethanol so as to be 1 mol / L with respect to the number of moles of each precursor to prepare an active metal compound solution. An oxalic acid solution was prepared by dissolving oxalic acid in an amount of 1.2 times the total number of moles of Fe + Mo + Mg in 90% ethanol to 1 mol / L. The active metal compound solution and the oxalic acid solution were mixed, and iron, magnesium and molybdenum were simultaneously precipitated with oxalic acid. After centrifugation (2000 rpm, 15 minutes), the supernatant was discarded, 90% ethanol was added, and the precipitate solution was vacuum-dried at 80 ° C. for 4 hours to prepare a precursor. The obtained precursor was calcined at 550 ° C. for 4 hours to obtain a catalyst. This catalyst had a particle size of 100 to 150 nm and a BET surface area of 250 m 2 / g.
前処理工程
得られた触媒を横型流通式反応炉中の５０ｍｇ石英ボードの上に配置し、水素／窒素＝１５０ｍＬ／１５０ｍＬ／ｍｉｎの気流中で６５０℃、２０分間還元処理した。
Pretreatment step The obtained catalyst was placed on a 50 mg quartz board in a horizontal flow reactor and subjected to reduction treatment at 650 ° C. for 20 minutes in a stream of hydrogen / nitrogen = 150 mL / 150 mL / min.
反応工程
実施例１と同様の反応工程により、炭素繊維を生成した。得られた炭素繊維は、繊維径１０〜３０ｎｍであった。また、収量の結果を表１に示す。
Reaction Step Carbon fibers were produced by the same reaction step as in Example 1. The obtained carbon fiber had a fiber diameter of 10 to 30 nm. The yield results are shown in Table 1.
比較例２（含浸法）
触媒の調製
酸化マグネシウム（関東化学株式会社製）の粉末に、硝酸鉄およびモリブデン酸アンモニウムを溶解した９０％エタノールを添加して、重量比で（Ｆｅ：Ｍｏ：Ｍｇ＝１０：７：８３）の割合の１ｍｏｌ／Ｌになるように９０％エタノールに溶解して、エタノール溶液を調製した。得られたエタノール溶液を８０℃で４時間真空乾燥し、前駆体を作製した。得られた前駆体を５５０℃で４時間焼成して触媒とした。この触媒は、粒径３００〜５００ｎｍでＢＥＴ表面積が７１ｍ２／ｇであった。
Comparative Example 2 (impregnation method)
Preparation of catalyst To a powder of magnesium oxide (manufactured by Kanto Chemical Co., Inc.), 90% ethanol in which iron nitrate and ammonium molybdate were dissolved was added, and in a weight ratio (Fe: Mo: Mg = 10: 7: 83) An ethanol solution was prepared by dissolving in 90% ethanol so that the ratio was 1 mol / L. The obtained ethanol solution was vacuum-dried at 80 ° C. for 4 hours to prepare a precursor. The obtained precursor was calcined at 550 ° C. for 4 hours to obtain a catalyst. This catalyst had a particle size of 300 to 500 nm and a BET surface area of 71 m 2 / g.
比較例１と同様の前処理工程および反応工程により、炭素繊維を生成した。得られた炭素繊維は、繊維径４０〜６０ｎｍであった。また、収量の結果を表１に示す。 Carbon fibers were produced by the same pretreatment process and reaction process as in Comparative Example 1. The obtained carbon fiber had a fiber diameter of 40 to 60 nm. The yield results are shown in Table 1.
比較例３（含浸法）
触媒の調製
酸化マグネシウム（関東化学株式会社製）の粉末に、硝酸鉄およびモリブデン酸アンモニウムを溶解した９０％エタノールを添加して、重量比で（Ｆｅ：Ｍｏ：Ｍｇ＝１０：７：８３）の割合の１ｍｏｌ／Ｌになるように９０％エタノールに溶解して、エタノール溶液を調製した。得られたエタノール溶液を８０℃で４時間真空乾燥し、触媒を作製した。この触媒は、粒径が３００〜５００ｎｍで、ＢＥＴ表面積が７０ｍ２／ｇであった。
Comparative Example 3 (impregnation method)
Preparation of catalyst To a powder of magnesium oxide (manufactured by Kanto Chemical Co., Inc.), 90% ethanol in which iron nitrate and ammonium molybdate were dissolved was added, and in a weight ratio (Fe: Mo: Mg = 10: 7: 83) An ethanol solution was prepared by dissolving in 90% ethanol so that the ratio was 1 mol / L. The obtained ethanol solution was vacuum-dried at 80 ° C. for 4 hours to prepare a catalyst. This catalyst had a particle size of 300 to 500 nm and a BET surface area of 70 m 2 / g.
実施例１と同様の反応工程を行ったが、炭素繊維を生成できなかった。 Although the reaction process similar to Example 1 was performed, carbon fiber was not able to be produced | generated.
表１から、本発明の方法により、従来の製造方法である比較例１と比べて、高収率で炭素繊維が得られることが分かる。また、図１から、本発明の方法により、微細な炭素繊維が得られることが分かる。このことから、本発明の製造方法では、工程が削減できるため低コストで、且つ高収率で炭素繊維を得ることができる。また、一般的手法である含浸法では、実施例１と同様の工程を行っても、炭素を含むガスと触媒は反応しなかった。 From Table 1, it can be seen that the carbon fiber can be obtained in a high yield by the method of the present invention as compared with Comparative Example 1 which is a conventional production method. Moreover, it turns out that a fine carbon fiber is obtained by the method of this invention from FIG. From this, in the manufacturing method of this invention, since a process can be reduced, carbon fiber can be obtained at a low cost and a high yield. Further, in the impregnation method which is a general method, even when the same steps as in Example 1 were performed, the gas containing carbon and the catalyst did not react.
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