JPH0624860A - Production of aluminous porous body - Google Patents
Production of aluminous porous bodyInfo
- Publication number
- JPH0624860A JPH0624860A JP18265092A JP18265092A JPH0624860A JP H0624860 A JPH0624860 A JP H0624860A JP 18265092 A JP18265092 A JP 18265092A JP 18265092 A JP18265092 A JP 18265092A JP H0624860 A JPH0624860 A JP H0624860A
- Authority
- JP
- Japan
- Prior art keywords
- alumina
- surface area
- specific surface
- porous body
- treatment
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
- C04B38/0045—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof by a process involving the formation of a sol or a gel, e.g. sol-gel or precipitation processes
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
- C04B2111/0081—Uses not provided for elsewhere in C04B2111/00 as catalysts or catalyst carriers
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、触媒燃焼器や、内燃エ
ンジンで使用される排ガス浄化、石油留分の処理、有機
合成等の不均質触媒用坦体等に利用可能な、高温下で高
い活性を維持しうるアルミナ質多孔体の製造に関する。BACKGROUND OF THE INVENTION The present invention is applicable to catalytic combustors, exhaust gas purification used in internal combustion engines, treatment of petroleum fractions, carriers for heterogeneous catalysts for organic synthesis, etc. The present invention relates to the production of an alumina porous body capable of maintaining high activity.
【０００２】[0002]
【従来の技術】かかる用途に使用される不均質触媒坦体
は、広い反応活性面積を得るために高い比表面積と様々
な処理によってもその比表面積が高く保持されると共
に、内燃エンジンの排ガス浄化においては８５０℃程
度、石油化学プロセス、有機合成等においては２００〜
６００℃等の高温に耐えうる耐熱性を有する必要があ
る。2. Description of the Related Art Heterogeneous catalyst carriers used for such applications have a high specific surface area in order to obtain a wide reaction active area and a high specific surface area by various treatments, and also purify exhaust gas of internal combustion engines. Is about 850 ° C, and in petrochemical processes, organic synthesis, etc.
It must have heat resistance to withstand high temperatures such as 600 ° C.
【０００３】この不均質触媒坦体における耐熱性の必要
性はさらに苛酷なものとなりつつある。例えば、排ガス
浄化用触媒としては、ＮＯｘの規制強化に伴い、従来の
一段階の酸化触媒処理から、酸化−還元の二段階触媒の
方向に進みつつあり、このため、触媒層をより高温のエ
ンジンに近接させる必要性が出てきており、１０００℃
前後での安定した耐熱性が要求されるようになった。The need for heat resistance in this heterogeneous catalyst carrier is becoming more severe. For example, as an exhaust gas purifying catalyst, with the tightening of NOx regulations, it is progressing from the conventional one-step oxidation catalyst treatment to a two-step oxidation-reduction catalyst. Therefore, the catalyst layer has a higher temperature in the engine. Need to be close to the
Stable heat resistance before and after has come to be required.
【０００４】一方において、近年触媒を用いて燃料と酸
素の反応を促進する接触燃焼法が注目を浴びている。こ
の接触燃焼法は、低温度での完全燃焼が可能、広範囲の
燃料／空気比で完全燃焼が可能、サーマルノックスの発
生が少ないなどの利点がある。この技術を確立するため
には１０００℃以上で安定な耐熱性を有する触媒担体の
開発が必要である。On the other hand, in recent years, a catalytic combustion method, which uses a catalyst to promote the reaction between fuel and oxygen, has been receiving attention. This catalytic combustion method has advantages such as complete combustion at a low temperature, complete combustion in a wide range of fuel / air ratio, and less generation of thermal knox. In order to establish this technology, it is necessary to develop a catalyst carrier that has stable heat resistance at 1000 ° C or higher.
【０００５】かかる耐熱性を有する触媒担体として加熱
処理後も高い比表面積を保持することが可能な多孔質ア
ルミナの使用が試みられている。As a catalyst carrier having such heat resistance, it has been attempted to use porous alumina capable of retaining a high specific surface area even after heat treatment.
【０００６】従来、かかるアルミナとして、アルミニウ
ム塩、アルミン酸塩の中和又は交換分解やアルミニウム
アマルガム、アルミニウムアルコキシドの加水分解で合
成する比表面積が高いγ−アルミナの使用が知られてい
る。[0006] Conventionally, as such alumina, it has been known to use γ-alumina having a high specific surface area which is synthesized by neutralization or exchange decomposition of aluminum salt or aluminate, or hydrolysis of aluminum amalgam or aluminum alkoxide.
【０００７】しかしながら、γ−アルミナは、１０００
〜１１００℃でα−アルミナに転移する。そのため、比
表面積が激減し反応活性面積が低下し、１０００℃以上
の高温域での使用はできず、その適用可能温度は精々６
００℃が限度である。However, γ-alumina is 1000
Transition to α-alumina at ˜1100 ° C. Therefore, the specific surface area is drastically reduced, the reaction active area is reduced, and it cannot be used in a high temperature range of 1000 ° C or higher, and the applicable temperature is 6 at best.
The limit is 00 ° C.
【０００８】また、特公昭５８−５３５６９号公報に
は、編目構造を有するα−アルミナ坦体が開示されてい
るが、その製造の過程でのアルミナのγ→α転移によっ
て急激に比表面積と強度が低下する。とくに、得られた
坦体の比表面積は精々３０ｍ2／ｇであって、γ−アル
ミナに比べると極めて低く、触媒担体能において劣った
ものとなる。Further, Japanese Patent Publication No. 58-53569 discloses an α-alumina carrier having a knitting structure, and the γ → α transition of alumina in the process of production thereof causes a sudden increase in specific surface area and strength. Is reduced. In particular, the specific surface area of the obtained carrier is at most 30 m 2 / g, which is extremely low as compared with γ-alumina, which is inferior in catalyst support ability.
【０００９】さらに、かかるアルミナ触媒担体の細孔分
布の制御と構造に関して多くの発明が開示されている。Further, many inventions have been disclosed regarding the control and structure of the pore distribution of the alumina catalyst carrier.
【００１０】例えば、特開昭５７−１２３８２０号公
報、特開昭５７−１３５７２１号公報、特開昭５７−１
７０８２２号公報には、カーボンブラツクの添加によっ
てバイモーダルな細孔半径分布を得ることが開示され、
また、特開昭５８−２５２号公報には、２種以上の酸化
物を水蒸気下で加熱処理することによって細孔容積を調
整することが、さらには、特開昭５８−１１９３４１号
公報には、アルミナ化合溶液を噴霧乾燥して全細孔容積
が０．８〜１．７ｍｌ／ｇ、比表面積が８０〜ｌ３５ｍ
2 ／ｇの多孔質表面を得ることが開示されている。さら
に、特開昭５８−２１６７４０号公報には、２種以上の
ベーマイトゾルを混合することによって、マルチモーダ
ルな細孔径分布を得ることが開示され、さらには、特開
平１−２５４２５４号公報には噴霧乾燥による方法が開
示されている。For example, JP-A-57-123820, JP-A-57-135721, and JP-A-57-1
No. 70822 discloses that a carbon black is added to obtain a bimodal pore radius distribution.
Further, in JP-A-58-252, it is possible to adjust the pore volume by heat-treating two or more kinds of oxides under steam, and further in JP-A-58-119341. , The alumina compound solution was spray-dried to have a total pore volume of 0.8 to 1.7 ml / g and a specific surface area of 80 to 135 m.
It is disclosed to obtain a porous surface of 2 / g. Further, JP-A-58-216740 discloses that a multimodal pore size distribution is obtained by mixing two or more kinds of boehmite sols, and further JP-A-1-254254 discloses. A method by spray drying is disclosed.
【００１１】しかしながら、以上の特許文献は、何れも
が比較的低温域における細孔構造の制御に係るもので、
１０００℃以上の高温域で使用されるアルミナ多孔体の
耐熱性の改善についての開示はない。However, all of the above patent documents relate to the control of the pore structure in a relatively low temperature range.
There is no disclosure about improvement in heat resistance of the alumina porous body used in a high temperature range of 1000 ° C. or higher.
【００１２】唯一、特開平３−１９９１２０号公報には
アルミナエアロゲルを臨界温度と臨界圧力を超えた状態
の下での乾燥によって、大きな比表面積と高温での優れ
た耐熱性を有するアルミナ多孔体を得る方法が記載され
ている。ところが、この製造法においては、乾燥に高温
高圧を必要とするため装置類が高価であって、且つ設備
の大型化ができないという欠点がある。[0012] The only one disclosed in Japanese Patent Application Laid-Open No. 3-199120 is a porous alumina body having a large specific surface area and excellent heat resistance at high temperature by drying the alumina airgel under the condition of exceeding the critical temperature and the critical pressure. The method of obtaining is described. However, this manufacturing method has the drawbacks that the equipment is expensive and the equipment cannot be upsized because high temperature and high pressure are required for drying.
【００１３】[0013]
【発明が解決しようとする課題】本発明の目的は、高温
域で優れた耐熱性を有し、且つ、高温域で高い比表面積
を保持できるアルミナ質多孔体を、大規模設備において
効率良く製造する方法を提供することにある。An object of the present invention is to efficiently produce an alumina porous body having excellent heat resistance in a high temperature range and capable of retaining a high specific surface area in a high temperature range in a large-scale facility. To provide a way to do.
【００１４】[0014]
【課題を解決するための手段】本発明は、アルミナ前駆
体となる空間容積を持つバルク体としてのゲルを１００
〜３５０℃で水蒸気または水熱処理することを特徴とす
るもので、水蒸気または水熱処理温度により高温域での
耐熱性が異なるという知見に基づいて完成した。According to the present invention, a gel as a bulk body having a space volume to be an alumina precursor is prepared.
It is characterized in that it is subjected to steam or hydrothermal treatment at ˜350 ° C., and it was completed based on the finding that the heat resistance in a high temperature region varies depending on the steam or hydrothermal treatment temperature.
【００１５】すなわち、化学式Ａｌ（ＯＲ）3 で表され
るアルミニウムアルコキシドまたはアルミニウムアルコ
キシド誘導体溶液を加水分解し得られたアルミナ前駆体
ゲルを１５０〜３５０℃の温度範囲で水蒸気又は水熱処
理することで得られるアルミナ質多孔体は高い比表面積
と優れた耐熱性を有する。That is, an alumina precursor gel obtained by hydrolyzing an aluminum alkoxide or aluminum alkoxide derivative solution represented by the chemical formula Al (OR) 3 is obtained by steam or hydrothermal treatment in the temperature range of 150 to 350 ° C. The porous alumina material has a high specific surface area and excellent heat resistance.
【００１６】Ｒはアルキル基を示すが、価格、金属濃度
より炭素数がｌ〜６のアルキル基が好ましい。Although R represents an alkyl group, an alkyl group having 1 to 6 carbon atoms is preferable in view of price and metal concentration.
【００１７】アルミニウムアルコキシド誘導体は、ＯＲ
の少なくとも一つ以上が多配座有機化合物で置換された
ものを示す。The aluminum alkoxide derivative is an OR
At least one of the above is substituted with a polydentate organic compound.
【００１８】多配座有機化合物としては、β−ジケト
ン、β−ケトエステル、アルカノールアミンが好ましい
が、アルミニウムアルコキシドの加水分解速度を低下さ
せる化合物であれば、とくに限定されない。The polydentate organic compound is preferably β-diketone, β-ketoester or alkanolamine, but is not particularly limited as long as it is a compound that reduces the hydrolysis rate of aluminum alkoxide.
【００１９】とくに、アルミナ前駆体ゲルを非水溶剤中
に浸した状態で水蒸気又は水熱処理することが、高い比
表面積を有するアルミナ質多孔体を製造する上で有効で
ある。In particular, steaming or hydrothermal treatment of the alumina precursor gel immersed in a non-aqueous solvent is effective for producing an alumina porous body having a high specific surface area.
【００２０】さらに、１００〜３５０℃、好ましくは、
２５０〜３５０℃のの温度範囲の水蒸気または水熱処理
によって、比表面積が２００ｍ2 ／ｇを越すアルミナ前
駆体が得られ、１１００℃以上の高温域、とくに、１２
００℃の加熱処理後も３０ｍ2 ／ｇを越す比表面積を有
するアルミナ質多孔体を製造することができる。Further, 100 to 350 ° C., preferably
By the steam or hydrothermal treatment in the temperature range of 250 to 350 ° C., an alumina precursor having a specific surface area of more than 200 m 2 / g can be obtained.
Even after the heat treatment at 00 ° C., an alumina porous body having a specific surface area exceeding 30 m 2 / g can be produced.
【００２１】アルミニウムアルコキシド誘導体のための
溶液としては、アルミニウム塩、アルミニウムアルコキ
シドあるいはアルミニウムアルコキシド誘導体が可溶な
有機溶剤であればとくに限定されないが、例えば、メタ
ノール、エタノール、プロパノールエチレングリコー
ル、メトキシエタノール、エトキシエタノール等のアル
コール類が好適に使用できる。The solution for the aluminum alkoxide derivative is not particularly limited as long as it is an organic solvent in which the aluminum salt, aluminum alkoxide or aluminum alkoxide derivative is soluble, and examples thereof include methanol, ethanol, propanol ethylene glycol, methoxyethanol and ethoxy. Alcohols such as ethanol can be preferably used.
【００２２】また、加水分解に際しては、アルミニウム
アルコキシドまたはアルミニウムアルコキシド誘導体の
０．５〜４倍モル量の水を用いることが好ましい。水量
が少ないとゲル化しないで溶液のままの状態となり、多
いと沈澱を生じる。In the hydrolysis, it is preferable to use 0.5 to 4 times the molar amount of water of the aluminum alkoxide or the aluminum alkoxide derivative. When the amount of water is small, the solution remains as it is without gelation, and when it is large, precipitation occurs.
【００２３】加水分解に際しての触媒として、塩酸、硝
酸などの鉱酸や酢酸などの有機酸等の酸や、不純物とし
ての金属を含まないアンモニアやアミンを用いることが
可能である。As a catalyst for the hydrolysis, it is possible to use an acid such as a mineral acid such as hydrochloric acid or nitric acid or an organic acid such as acetic acid, or ammonia or amine containing no metal as an impurity.
【００２４】高温処理は低温域処理に比較して比表面積
を若干減少させるが、高温域での耐熱性を増加させ、水
蒸気または水熱条件を変えることで使用温度により希望
の耐熱性と比表面積を選べる。The high temperature treatment slightly reduces the specific surface area as compared with the low temperature treatment, but it increases the heat resistance in the high temperature region and changes the steam or hydrothermal conditions to obtain the desired heat resistance and specific surface area depending on the operating temperature. Can be selected.
【００２５】本発明によればアルミナ単成分系のみでな
くゲル作製段階で他の成分を均一に混合することが可能
であることは言うまでもない。It goes without saying that according to the present invention, not only the alumina single component system, but also other components can be uniformly mixed at the stage of gel preparation.
【００２６】[0026]
【作用】本発明におけるアルミナ前駆体ゲルの使用は、
広範囲な熱処理条件、金属濃度で行うためにゲルの方が
取り扱い易いことによる。アルミナ前駆体ゲルに代わっ
て、アルミナ質のゾルを用いることも可能であるが、高
濃度化が困難であり、水系においては、ゾルを安定化す
るために酸を用いる必要がある。この酸の使用のため
に、水蒸気または水熱処理に際して処理槽内部が腐食さ
れる。そのため、処理槽にテフロン等の特殊処理が必要
となる。また、処理温度が２００℃以下と限定されるこ
とになる。さらには水系では安定なゾルを得ることが困
難である。さらに、アルミナ前駆体ゲルの使用によっ
て、触媒金属、焼結抑制剤等の添加に際しての他の成分
の均一混合が容易となる。The function of the alumina precursor gel in the present invention is
This is because the gel is easier to handle because it is performed under a wide range of heat treatment conditions and metal concentrations. It is possible to use an alumina sol instead of the alumina precursor gel, but it is difficult to increase the concentration, and in an aqueous system, it is necessary to use an acid to stabilize the sol. Due to the use of this acid, the inside of the treatment tank is corroded during steam or hydrothermal treatment. Therefore, special treatment such as Teflon is required for the treatment tank. Further, the processing temperature is limited to 200 ° C. or lower. Furthermore, it is difficult to obtain a stable sol in an aqueous system. Further, the use of the alumina precursor gel facilitates uniform mixing of other components when adding the catalyst metal, the sintering inhibitor and the like.
【００２７】水蒸気又は水熱処理の温度としては、べー
マイトの結晶を成長させるためには１００℃以上が必要
であるが、３５０℃以下で充分である。好ましくは、１
５０〜３００℃である。とくに、１００〜２５０℃の温
度範囲の水蒸気または水熱処理によって比表面積が１５
０ｍ2 ／ｇを越すアルミナ前駆体の作製が可能となる。
さらに、２５０〜３５０℃の温度範囲での水蒸気または
水熱処理によって、１２００℃の加熱処理後も３０ｍ2
／ｇ以上の比表面積を保持可能なアルミナ前駆体が製造
可能となる。The temperature of the steam or hydrothermal treatment needs to be 100 ° C. or higher for growing the boehmite crystal, but 350 ° C. or lower is sufficient. Preferably 1
It is 50 to 300 ° C. Particularly, the specific surface area is 15 by steam or hydrothermal treatment in the temperature range of 100 to 250 ° C.
It is possible to produce an alumina precursor having a content of more than 0 m 2 / g.
Furthermore, by steam or hydrothermal treatment in the temperature range of 250 to 350 ° C., 30 m 2 after heat treatment at 1200 ° C.
It is possible to manufacture an alumina precursor capable of maintaining a specific surface area of not less than / g.
【００２８】オートクレーブ処理により、細孔分布の制
御と機械的特性の向上に加えて、耐熱性に優れたアルミ
ナ質多孔体が得られる。By the autoclave treatment, in addition to controlling the pore distribution and improving the mechanical properties, an alumina porous body having excellent heat resistance can be obtained.
【００２９】ゲルを用いる事でアルミナ成分を空間へ固
定することができる。この状態で水蒸気又は水熱処理す
ることにより、空間的広がりを保持したままベーマイト
の結晶が成長できる。また、ベーマイトの結晶は針状に
成長することが知られている。従って、得られたアルミ
ナ前駆体はベーマイトの針状結晶が絡み合い、空孔を多
く含んだものとなっていると考えられる。結果として高
い比表面積と高い細孔容積が得られる。By using a gel, the alumina component can be fixed in the space. By performing steam or hydrothermal treatment in this state, boehmite crystals can be grown while maintaining the spatial expansion. Further, it is known that boehmite crystals grow like needles. Therefore, it is considered that the obtained alumina precursor contains a large number of voids due to the interlocking of boehmite needle-like crystals. The result is a high specific surface area and a high pore volume.
【００３０】水蒸気または水熱処理温度が高くなるとア
ルミナ前駆体中のベーマイトの結晶が大きくなり、低温
での処理に比べ比表面積は小さくなるが細孔径が大きく
なる。また、理由は明確でないが、θ相の安定領域が広
くなるので、α相への転移が抑えられ高温での比表面積
が高く保持されたと考えられる。When the temperature of steam or hydrothermal treatment becomes high, the crystal of boehmite in the alumina precursor becomes large, and the specific surface area becomes small as compared with the treatment at low temperature, but the pore diameter becomes large. Further, although the reason is not clear, it is considered that the stable region of the θ phase is widened, so that the transition to the α phase is suppressed and the high specific surface area is maintained at a high temperature.
【００３１】水は大きな表面張力を有するため乾燥時の
毛管応力の発生によりゲルの細孔を潰してしまう。ゲル
を直接水に漬けることを避けることにより水の毛管応力
によるゲルの収縮を避けることが可能となる。結果とし
てより高い比表面積が保持されると思われる。Since water has a large surface tension, capillary stress is generated during drying and the pores of the gel are crushed. By avoiding soaking the gel directly in water, it is possible to avoid shrinkage of the gel due to capillary stress of water. It seems that a higher specific surface area is retained as a result.
【００３２】[0032]
実施例ｌ エチルアセテートアルミニウムジイソプロピレート２７
４ｇをエタノール５００ｍｌに溶解した後７２ｍｌの水
を加え加水分解しゲルを得た。得られたゲルをオートク
レーブ中で２７０℃で保圧弁を用い２０気圧以下に圧力
を保ち１０時間水熱処理した。乾燥後、６００、８０
０、１０００、１１００、１２００℃で５時間加熱処理
した。得られたアルミナ前駆体は１０００℃までｌ００
ｍ2 ／ｇを越す比表面積を保持し、さらに１２００℃で
５時間加熱処理後も５０．５ｍ2 ／ｇという高い比表面
積を保持していた。６００℃から８００℃ではγ相が、
１０００℃以上ではθ相が主結晶相であった。１１００
℃まではα相への転移は見られず、１２００℃の加熱処
理において微量のα相が確認されたのみであった。ま
た、１０００℃までの温度で加熱処理したサンプルは
１．００ｍｌ／ｇを越す大きな気孔容積を維持し、１２
００℃でも０．４５ｍｌ／ｇと他に類をみない高い値で
あった。乾燥後及び各温度で５時間加熱処理後の結晶
相、比表面積及び細孔容積をそれぞれ表ｌに示す。比表
面積及び細孔容積は窒素吸着によるＢＥＴ法により測定
したものである。Example l Ethyl acetate aluminum diisopropylate 27
After dissolving 4 g in 500 ml of ethanol, 72 ml of water was added and hydrolyzed to obtain a gel. The obtained gel was hydrothermally treated in an autoclave at 270 ° C. for 10 hours while maintaining the pressure below 20 atm using a pressure-holding valve. 600, 80 after drying
Heat treatment was performed at 0, 1000, 1100, and 1200 ° C. for 5 hours. The obtained alumina precursor was 100 up to 1000 ° C.
It had a specific surface area of more than m 2 / g and further had a high specific surface area of 50.5 m 2 / g even after heat treatment at 1200 ° C. for 5 hours. At 600 ° C to 800 ° C, the γ phase
At 1000 ° C. or higher, the θ phase was the main crystalline phase. 1100
No transition to the α phase was observed up to ° C, and only a trace amount of the α phase was confirmed in the heat treatment at 1200 ° C. In addition, the sample heat-treated at a temperature up to 1000 ° C. maintained a large pore volume exceeding 1.00 ml / g,
Even at 00 ° C., it was 0.45 ml / g, which was a high value unlike any other. Table 1 shows the crystal phase, the specific surface area, and the pore volume after drying and after heating for 5 hours at each temperature. The specific surface area and the pore volume are measured by the BET method using nitrogen adsorption.
【００３３】[0033]
【表１】 実施例２ 実施例ｌと同様の方法で得られたゲルをオートクレーブ
中、１４０、１７０、２００、２４０、２７０℃で保圧
弁を用い１０気圧以下に圧力を保ち、６時間水熱処理し
た。乾燥後、５００、８００、１０００、１１００、１
２００℃で、５時間加熱処理した。低い水熱処理温度で
得られたアルミナ前駆体ほど高い比表面積を持ち、１０
００℃以下の加熱処理に対して有効であることがわか
る。一方、水熱処理温度を上げると１０００℃以上の高
温域での耐熱性が大幅に向上する。２７０℃処理アルミ
ナ前駆体は１２００℃でも３５．０ｍ2 ／ｇと高い比表
面積を保持した。乾燥後及び各温度で５時間加熱処理後
の比表面積を表２に示す。[Table 1] Example 2 The gel obtained in the same manner as in Example 1 was hydrothermally treated in an autoclave at 140, 170, 200, 240, and 270 ° C. for 6 hours while maintaining the pressure at 10 atmospheric pressure or less using a pressure-holding valve. After drying, 500, 800, 1000, 1100, 1
It heat-processed at 200 degreeC for 5 hours. The alumina precursor obtained at a lower hydrothermal treatment temperature has a higher specific surface area and 10
It can be seen that it is effective for heat treatment at 00 ° C or lower. On the other hand, when the hydrothermal treatment temperature is raised, the heat resistance in a high temperature range of 1000 ° C. or higher is significantly improved. The 270 ° C.-treated alumina precursor retained a high specific surface area of 35.0 m 2 / g even at 1200 ° C. Table 2 shows the specific surface area after drying and after heating at each temperature for 5 hours.
【００３４】[0034]
【表２】 実施例３ 実施例２で得られたアルミナ前駆体を１１００℃で、さ
らに１０、５０、１００時間加熱処理した後、比表面積
を測定した。２７０℃水熱処理アルミナ前駆体は１００
時間の加熱処理後も５８．４ｍ2 ／ｇと２００℃以下の
水熱処理温度のアルミナ前駆体の比表面積が１０ｍ2 ／
ｇ以下であるのに比べ、高い比表面積を保持している。
このように２７０℃の水熱処理で得られたアルミナ前駆
体は高温での長時間の加熱処理に対しても優れた耐熱性
を持つ。加熱処理後の比表面積の変化を表３に示す。[Table 2] Example 3 The alumina precursor obtained in Example 2 was heat-treated at 1100 ° C. for 10, 50 and 100 hours, and then the specific surface area was measured. 270 ° C hydrothermal treatment alumina precursor is 100
Even after heat treatment for 5 hours, the specific surface area of the alumina precursor at a hydrothermal treatment temperature of 58.4 m 2 / g and 200 ° C. or lower is 10 m 2 / g.
It has a high specific surface area as compared with g or less.
As described above, the alumina precursor obtained by the hydrothermal treatment at 270 ° C. has excellent heat resistance even when heat-treated at a high temperature for a long time. Table 3 shows the change in specific surface area after the heat treatment.
【００３５】[0035]
【表３】 比較例ｌ 実施例ｌと同様の方法で得られたゲルを大気中乾燥させ
得られたゲルを実施例ｌ，３と同様に加熱処理した。実
施例に比べ低い１０００℃以上の加熱処理温度で急激な
比表面積の低下を伴いα相へ転移した。比表面積の変化
を表２に示す。[Table 3] Comparative Example 1 The gel obtained in the same manner as in Example 1 was dried in the air, and the obtained gel was heat treated in the same manner as in Examples 1 and 3. At a heat treatment temperature of 1000 ° C. or higher, which is lower than in the examples, the α phase was transformed with a rapid decrease in specific surface area. Table 2 shows changes in the specific surface area.
【００３６】比較例２ 市販のγ−アルミナ（Ｃｏｎｄｅａ社製、商標名 ＰＵ
ＲＬＯＸ：ＳＢａ−２３０）を実施例ｌ、３と同様に加
熱処理した。１０００℃以下の加熱処理ではｌ００ｍ2
／ｇ以上の比表面積を保持したが、１１００℃以上の加
熱処理により急激な比表面積の低下を伴いα相へ転移し
た。比表面積の変化を表２と表３に示す。Comparative Example 2 Commercially available γ-alumina (trade name PU manufactured by Condea Corporation)
RLOX: SBa-230) was heat treated in the same manner as in Examples 1 and 3. 100 m 2 for heat treatment below 1000 ° C
Although the specific surface area was kept above / g, the heat treatment at 1100 ° C. or above caused a rapid decrease in the specific surface area and transition to the α phase. The changes in specific surface area are shown in Tables 2 and 3.
【００３７】実施例４ 実施例ｌと同様の方法で得られたゲルをガラス容器中に
置き、水に直接触れることなくオートクレーブ中にセッ
トした。１７０℃で保圧弁を用い５気圧以下に圧力を保
ち６時間水蒸気処理した。得られたアルミナ前駆体の比
表面積は３００ｍ2 ／ｇを越す値であった。エタノール
に浸さずに水蒸気又は水熱処理したアルミナ前駆体と比
べ加熱処理後も大きな比表面積を保持した。乾燥後及び
各温度で５時問加熱処理後の比表面積を表４に示す。Example 4 The gel obtained in the same manner as in Example 1 was placed in a glass container and set in an autoclave without directly touching water. Using a pressure-retaining valve at 170 ° C., the pressure was maintained at 5 atm or less and steam treatment was performed for 6 hours. The specific surface area of the obtained alumina precursor was a value exceeding 300 m 2 / g. A large specific surface area was maintained after the heat treatment as compared with the alumina precursor that was subjected to steam or hydrothermal treatment without being immersed in ethanol. Table 4 shows the specific surface area after drying and after the heat treatment for 5 hours at each temperature.
【００３８】[0038]
【表４】 上記実施例によるアルミナ系多孔体はバルク体であるの
で、触媒担体として用いる場合、従来法によるアルミナ
担体のように脱水、成形、乾燥による造粒成形の工程を
行う必要がない。[Table 4] Since the alumina-based porous body according to the above-mentioned embodiment is a bulk body, when it is used as a catalyst carrier, it is not necessary to perform the steps of dehydration, molding, and granulation molding by drying unlike the conventional alumina carrier.
【００３９】[0039]
【発明の効果】本発明によって以下の効果を奏する。The present invention has the following effects.
【００４０】（１）高温での耐熱性の優れた触媒担体な
どに使用可能なアルミナ質多孔体を得ることができる。(1) It is possible to obtain an alumina-based porous material which can be used as a catalyst carrier having excellent heat resistance at high temperatures.
【００４１】（２）超臨界条件下でのアルミナエアロゲ
ルの作製と比べ高温高圧力容器を必要としないため、装
置をシンプルにでき大型化が可能であり量産性に富む。
また、装置の価格も安くすることができる。(2) Compared with the production of alumina airgel under supercritical conditions, a high temperature and high pressure vessel is not required, so that the apparatus can be simplified and the size can be increased, and the mass productivity is excellent.
Also, the price of the device can be reduced.
【００４２】（３）得られるアルミナ質多孔体が１００
０℃を越す高温でも優れた耐熱性を有する。とくに、２
５０℃以上の水蒸気叉は水熱処理で得られたアルミナ前
駆体は１１００℃以上の高温域でこれまでにない優れた
耐熱性を有する。(3) The obtained alumina porous material is 100
It has excellent heat resistance even at high temperatures exceeding 0 ° C. Especially 2
The alumina precursor obtained by steam or hydrothermal treatment at 50 ° C. or higher has unprecedented excellent heat resistance in a high temperature range of 1100 ° C. or higher.
Claims (2)
Ｒ）3 で表されるアルミニウムアルコキシドまたはアル
ミニウムアルコキシド誘導体溶液を加水分解し得られた
アルミナ前駆体ゲルを１００〜３５０℃の温度範囲で水
蒸気または水熱処理後乾燥加熱処理するアルミナ質多孔
体の製造方法。1. The chemical formula Al (O
R) 3 A method for producing an alumina porous body, in which an aluminum precursor gel obtained by hydrolyzing an aluminum alkoxide or aluminum alkoxide derivative solution is subjected to steam or hydrothermal treatment and then dry heat treatment in a temperature range of 100 to 350 ° C. .
体ゲルの水蒸気または水熱処理を、オートクレーブ中に
設置した解放容器中で、直接水に浸すことなく行うアル
ミナ質多孔体の製造方法。2. The method for producing an alumina porous body according to claim 1, wherein the steam or hydrothermal treatment of the alumina precursor gel is carried out in an open container installed in an autoclave without being directly immersed in water.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18265092A JPH0624860A (en) | 1992-07-09 | 1992-07-09 | Production of aluminous porous body |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP18265092A JPH0624860A (en) | 1992-07-09 | 1992-07-09 | Production of aluminous porous body |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0624860A true JPH0624860A (en) | 1994-02-01 |
Family
ID=16122023
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP18265092A Pending JPH0624860A (en) | 1992-07-09 | 1992-07-09 | Production of aluminous porous body |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0624860A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6797120B2 (en) | 1999-01-29 | 2004-09-28 | Kao Corporation | Method of manufacturing pulp mold formed body |
| US9090951B2 (en) | 2007-12-20 | 2015-07-28 | Voestalpine Stahl Gmbh | Method for producing coated and hardened components of steel and coated and hardened steel strip therefor |
| CN112592150A (en) * | 2021-03-04 | 2021-04-02 | 中国人民解放军国防科技大学 | Preparation method of alumina-silica aerogel heat-insulation composite material |
-
1992
- 1992-07-09 JP JP18265092A patent/JPH0624860A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6797120B2 (en) | 1999-01-29 | 2004-09-28 | Kao Corporation | Method of manufacturing pulp mold formed body |
| US9090951B2 (en) | 2007-12-20 | 2015-07-28 | Voestalpine Stahl Gmbh | Method for producing coated and hardened components of steel and coated and hardened steel strip therefor |
| CN112592150A (en) * | 2021-03-04 | 2021-04-02 | 中国人民解放军国防科技大学 | Preparation method of alumina-silica aerogel heat-insulation composite material |
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