JP2011036748A - Catalyst for selectively hydrogenating aromatic nitro compound, method for producing and regenerating the catalyst, and method for selectively hydrogenating aromatic nitro compound by using the catalyst - Google Patents

Catalyst for selectively hydrogenating aromatic nitro compound, method for producing and regenerating the catalyst, and method for selectively hydrogenating aromatic nitro compound by using the catalyst Download PDF

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JP2011036748A
JP2011036748A JP2009184034A JP2009184034A JP2011036748A JP 2011036748 A JP2011036748 A JP 2011036748A JP 2009184034 A JP2009184034 A JP 2009184034A JP 2009184034 A JP2009184034 A JP 2009184034A JP 2011036748 A JP2011036748 A JP 2011036748A
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silver
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selective hydrogenation
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hydrogenation catalyst
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JP5543150B2 (en
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Atsushi Satsuma
篤 薩摩
Kenichi Shimizu
研一 清水
Yuji Miyamoto
裕士 宮本
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NE Chemcat Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a catalyst for selectively and economically hydrogenating only a nitro group even when the nitro group, a carbon-carbon double bond, a halogen atom bonded to an aromatic ring, and groups such as an aromatic ketonic carbonyl group, an aromatic carboxylate group, an aromatic amidic carbonyl group and an aromatic nitrile group are present in one and the same compound and to provide a method for selectively hydrogenating an aromatic nitro compound by using such the catalyst. <P>SOLUTION: The catalyst for selectively hydrogenating the aromatic nitro compound is obtained by depositing silver and/or silver oxide on alumina as a silver component and has the deposited silver component of 0.5-3 nm average particle size. There is also provided a method for producing the catalyst. The method for selectively hydrogenating the nitro group of the aromatic nitro compound comprises a step of heating/mixing the aromatic nitro compound, the catalyst, an organic solvent and hydrogen gas. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

本発明は、芳香族ニトロ化合物の選択的水素化触媒、その製造方法および再生方法並びにこれを用いた芳香族ニトロ化化合物の選択的水素化方法に関する。   The present invention relates to a selective hydrogenation catalyst for aromatic nitro compounds, a production method and a regeneration method thereof, and a selective hydrogenation method for aromatic nitrate compounds using the same.

芳香族ニトロ化合物の水素化により、種々の誘導体が得られるが、これらは、インクジェットインキの画質の向上剤の原料や、遺伝子導入剤の原料、医薬、農薬の中間体、感光性高分子化合物原料、成型用樹脂組成物原料など、機能性重合体の原料としての利用が検討されている。このような芳香族ニトロ化合物の誘導体の例としては、アミノスチレン等が知られている。   Various derivatives are obtained by hydrogenation of aromatic nitro compounds. These are raw materials for image quality improvers for inkjet inks, raw materials for gene introduction agents, intermediates for pharmaceuticals and agricultural chemicals, and raw materials for photosensitive polymer compounds. Utilization as a raw material for a functional polymer such as a molding resin composition raw material has been studied. As an example of such an aromatic nitro compound derivative, aminostyrene or the like is known.

ところで、芳香族ニトロ化合物には、ニトロ基の他、水素化または水素化分解を受ける官能基を1または複数持つものも存在する。そしてこのような芳香族ニトロ化合物では、官能基のうち一部のみを選択的に水素化または水素化分解することが求められる場合があり、これに適した触媒も知られている。   By the way, some aromatic nitro compounds have one or more functional groups that undergo hydrogenation or hydrogenolysis in addition to the nitro group. In such an aromatic nitro compound, it may be required to selectively hydrogenate or hydrocrack only a part of the functional group, and a catalyst suitable for this is also known.

例えば、官能基としてニトロ基の他、炭素−炭素二重結合を持つ芳香族ニトロ化合物は、いずれの基も比較的水素化されやすいが、これらのうちニトロ基を選択的に還元する触媒の例としては、白金担持炭素触媒を次亜リン酸およびバナジウムで修飾した触媒が知られており(非特許文献1)、他にも金のナノ粒子をチタニアに担持した触媒が知られている(非特許文献2)。   For example, an aromatic nitro compound having a carbon-carbon double bond in addition to a nitro group as a functional group is relatively easily hydrogenated, but examples of catalysts that selectively reduce the nitro group among these groups. Are known in which a platinum-supported carbon catalyst is modified with hypophosphorous acid and vanadium (Non-patent Document 1), and other catalysts in which gold nanoparticles are supported on titania are known (non-patent document 1). Patent Document 2).

しかしながら、非特許文献1記載の触媒は、触媒金属として比較的高価なプラチナを用いるものであり、また、非特許文献2記載の触媒では、比較的高価な金を使用することで、いずれも触媒自体のコストが高くなるという問題があった。   However, the catalyst described in Non-Patent Document 1 uses a relatively expensive platinum as a catalyst metal, and the catalyst described in Non-Patent Document 2 uses a relatively expensive gold, so There was a problem that the cost of itself increased.

更に、非特許文献1記載の触媒は、調製段階でリン化合物やバナジウム化合物による修飾工程が必要であるため、製造工程が複雑になるという問題もあった。   Furthermore, the catalyst described in Non-Patent Document 1 has a problem that the manufacturing process becomes complicated because a modification step with a phosphorus compound or a vanadium compound is necessary in the preparation stage.

一方、芳香族ニトロ化合物の官能基の一部を選択的に水素化または水素化分解する触媒として、担体にシリカを使用し、活性種としての金属に比較的廉価な銀を使用する触媒も知られている(非特許文献3)。   On the other hand, as a catalyst for selectively hydrogenating or hydrocracking a part of functional groups of an aromatic nitro compound, a catalyst using silica as a support and relatively inexpensive silver as a metal as an active species is also known. (Non-patent Document 3).

しかしながら、本発明者らの試験によれば、非特許文献3の触媒は水素化反応に使用するに伴って活性が低下し、しかもその再生が困難であるものであった。   However, according to the tests of the present inventors, the activity of the catalyst of Non-Patent Document 3 decreases as it is used for the hydrogenation reaction, and its regeneration is difficult.

H.-U.Blaser, U. Siegrist, H. Steiner, in Aromatic Nitro Compounds: FineChemicals through Heterogeneous Catalysis, R. A. Sheldon, H. van. Bekkum, Eds.(Wiley-VCH, Weinheim, Germany, 2001), p.389H.-U.Blaser, U. Siegrist, H. Steiner, in Aromatic Nitro Compounds: FineChemicals through Heterogeneous Catalysis, RA Sheldon, H. van. Bekkum, Eds. (Wiley-VCH, Weinheim, Germany, 2001), p. 389 "Science", 2006, 313, 332 A. Corma, P. Serna,"Science", 2006, 313, 332 A. Corma, P. Serna, "Chem. Commun.", 2005, 5298-5300"Chem. Commun.", 2005, 5298-5300

従って本発明は、ニトロ基と、炭素−炭素二重結合、芳香環結合ハロゲン原子、芳香族ケトン性カルボニル基、芳香族カルボン酸エステル基、芳香族アミド性カルボニル基、芳香族ニトリル基等の基が同一化合物内に存在していても、後者の基を水素化または水素化分解することなく、ニトロ基のみを選択的、かつ経済的に水素化することのできる触媒を見出し、更に、このような触媒を使用した芳香族ニトロ化合物の選択的水素化方法の提供をその目的とするものである。   Accordingly, the present invention provides a nitro group and a group such as a carbon-carbon double bond, an aromatic ring-bonded halogen atom, an aromatic ketonic carbonyl group, an aromatic carboxylic acid ester group, an aromatic amido carbonyl group, and an aromatic nitrile group. Are present in the same compound, a catalyst capable of selectively and economically hydrogenating only the nitro group without hydrogenation or hydrogenolysis of the latter group has been found. It is an object of the present invention to provide a method for selective hydrogenation of aromatic nitro compounds using a simple catalyst.

本発明者らは、芳香族ニトロ化合物の芳香環または複素環に結合したニトロ基を選択的に水素化することができる触媒を見出すべく、鋭意検討した結果、特定の粒径の銀成分をアルミナへ担持させた触媒が、上記課題を解決するものであることを見出し本発明を完成するに至った。   As a result of intensive investigations to find a catalyst capable of selectively hydrogenating a nitro group bonded to an aromatic ring or a heterocyclic ring of an aromatic nitro compound, the present inventors have determined that a silver component having a specific particle size is alumina. The present inventors have found that the catalyst supported on the catalyst can solve the above-mentioned problems and have completed the present invention.

すなわち本発明は、アルミナに、銀成分として銀および/または銀酸化物を担持せしめてなり、担持された銀成分の平均粒子径が0.5〜3nmであることを特徴とする芳香族ニトロ化合物の選択的水素化触媒である。   That is, the present invention is an aromatic nitro compound characterized in that silver and / or silver oxide is supported on alumina as the silver component, and the average particle size of the supported silver component is 0.5 to 3 nm. Is a selective hydrogenation catalyst.

また本発明は、アルミナに銀塩水溶液を含浸させ、乾燥した後、酸化雰囲気での焼成および還元処理を行うことを特徴とする上記選択的水素化触媒の製造方法である。   The present invention also provides the method for producing a selective hydrogenation catalyst as described above, wherein alumina is impregnated with an aqueous silver salt solution and dried, followed by calcination and reduction treatment in an oxidizing atmosphere.

更に本発明は、芳香族ニトロ化合物、有機溶剤、前記選択的水素化触媒および水素ガスを加熱条件下混合することを特徴とする芳香族ニトロ化合物のニトロ基の選択的水素化方法である。   Furthermore, the present invention is a method for selectively hydrogenating a nitro group of an aromatic nitro compound, which comprises mixing an aromatic nitro compound, an organic solvent, the selective hydrogenation catalyst, and hydrogen gas under heating conditions.

本発明の官能基選択的水素化触媒および水素化方法によれば、芳香族ニトロ化合物の芳香環または複素環に結合したニトロ基を、高い転化性と選択性をもって水素化することができる。しかも、同一化合物中に炭素−炭素二重結合、芳香環結合ハロゲン原子、芳香族ケトン性カルボニル基、芳香族カルボン酸エステル基、芳香族アミド性カルボニル基、芳香族ニトリル基が存在していてもこれらの官能基は実質的に水素化も水素化分解も受けることがない。   According to the functional group selective hydrogenation catalyst and hydrogenation method of the present invention, a nitro group bonded to an aromatic ring or a heterocyclic ring of an aromatic nitro compound can be hydrogenated with high conversion and selectivity. Moreover, even if a carbon-carbon double bond, an aromatic ring bond halogen atom, an aromatic ketonic carbonyl group, an aromatic carboxylic acid ester group, an aromatic amido carbonyl group, or an aromatic nitrile group is present in the same compound. These functional groups are substantially neither hydrogenated nor hydrocracked.

しかも、本発明の触媒は、ある程度の使用によって触媒の活性が低下した場合も、複雑な工程を経ることなく、再生することが可能であり、経済性の高いものである。   Moreover, the catalyst of the present invention can be regenerated without going through a complicated process even when the activity of the catalyst is reduced by a certain amount of use, and is highly economical.

以下、本発明について更に詳細に説明する。なお、本願の特許請求の範囲及び明細書において、下記の用語は以下の通りの意味で用いられる。   Hereinafter, the present invention will be described in more detail. In the claims and specification of the present application, the following terms are used in the following meanings.

「芳香族ニトロ基」 芳香環(芳香族の炭化水素環)または複素環に結合したニトロ基

「芳香環結合ハロゲン原子」 芳香環または複素環に結合したハロゲン原子。
「芳香族ケトン性カルボニル基」 ケトンを構成するカルボニル基であって、該カルボニル基が結合する二つの炭素原子のうちの少なくとも一方が芳香環または複素環の一員であるカルボニル基。
「芳香族カルボン酸エステル基」 カルボン酸エステルを構成するカルボニル基が結合する炭素原子が芳香環または複素環の一員であるカルボン酸エステル基。
「芳香族アミド性カルボニル基」 アミドを構成するカルボニル基であって、該カルボニル基が結合する炭素原子が芳香環または複素環の一員であるカルボニル基。
「芳香族ニトリル基」 芳香環または複素環に結合したニトリル基(−CN)。
“Aromatic nitro group” A nitro group bonded to an aromatic ring (aromatic hydrocarbon ring) or heterocyclic ring.
“Aromatic ring-bonded halogen atom” A halogen atom bonded to an aromatic ring or a heterocyclic ring.
“Aromatic ketonic carbonyl group” A carbonyl group constituting a ketone, wherein at least one of two carbon atoms to which the carbonyl group is bonded is a member of an aromatic ring or a heterocyclic ring.
“Aromatic carboxylic acid ester group” A carboxylic acid ester group in which the carbon atom to which the carbonyl group constituting the carboxylic acid ester is bonded is a member of an aromatic ring or a heterocyclic ring.
“Aromatic amido carbonyl group” A carbonyl group constituting an amide, wherein the carbon atom to which the carbonyl group is bonded is a member of an aromatic ring or a heterocyclic ring.
“Aromatic nitrile group” A nitrile group (—CN) bonded to an aromatic ring or a heterocyclic ring.

[ 担 体 ]
本発明の芳香族ニトロ化合物の選択的水素化触媒(以下、「選択的水素化触媒」と略称することがある)の担体としては、アルミナが使用される。使用されるアルミナの種類は特に限定されないが、耐熱性が高く、比表面積値の大きなアルミナが好ましく、例えば、θアルミナ、γアルミナが用いられ、特に耐熱性の点からはθアルミナが好ましい。
[Body]
Alumina is used as a carrier for the selective hydrogenation catalyst of the aromatic nitro compound of the present invention (hereinafter sometimes abbreviated as “selective hydrogenation catalyst”). The type of alumina used is not particularly limited, but alumina having high heat resistance and a large specific surface area value is preferable. For example, θ alumina and γ alumina are used, and θ alumina is particularly preferable from the viewpoint of heat resistance.

また、担体として使用されるアルミナの比表面積値については特に限定されないが、30〜3000m/gが好ましく、50〜500m/gが特に好ましい。比表面積値が小さすぎると触媒の製造や再生時にシンタリングを起こし易く、出来上がった触媒が充分な活性を発揮できないことがある。一方、比表面積値が大きすぎると銀成分の分散性が悪くなり、この場合も充分な活性を発揮する触媒を得られないことがある。 Although there is no particular limitation on the specific surface area of the alumina used as the carrier, preferably 30~3000m 2 / g, 50~500m 2 / g is particularly preferred. If the specific surface area is too small, sintering is likely to occur during the production and regeneration of the catalyst, and the completed catalyst may not exhibit sufficient activity. On the other hand, if the specific surface area value is too large, the dispersibility of the silver component deteriorates, and in this case as well, a catalyst that exhibits sufficient activity may not be obtained.

更に、使用されるアルミナの粒径については特に限定されないが、そのメジアン径が0.5〜500μmの範囲であることが好ましく、5〜500μmがより好ましい。粒径が小さすぎるアルミナは、全体的にみて細孔容積が小さくなることがあり、細孔容積の小さなアルミナは触媒としての活性低下の要因となり、さらには耐毒性が低下してしまうことがある。一方、粒径が大きすぎると、アルミナ粒子の質量当たりの比表面積値が小さくなり、銀成分の分散性が低下し、充分な活性が得られないことがある。   Further, the particle diameter of the alumina used is not particularly limited, but the median diameter is preferably in the range of 0.5 to 500 μm, more preferably 5 to 500 μm. Alumina with a particle size that is too small may reduce the pore volume as a whole, and alumina with a small pore volume may cause a decrease in activity as a catalyst, and may further reduce toxicity resistance. . On the other hand, if the particle size is too large, the specific surface area value per mass of the alumina particles becomes small, the dispersibility of the silver component is lowered, and sufficient activity may not be obtained.

[ 銀 粒 子 ]
本発明の選択的水素化触媒の活性種である銀成分は、銀および/または銀酸化物である。これら銀成分の担持量は特に限定されないが、アルミナ担体1g当たりの銀元素に換算して、1.0μmol〜5mmolが好ましく、10μmol〜3mmolが特に好ましく、100μmol〜2mmolが最も好ましい。重量比で見た場合の、アルミナに対する銀成分の銀換算量は10wt%以下が望ましく、特に5wt%が望ましい。銀成分の量が少なすぎると充分な活性が得られないことがあり反応にも時間がかかることがある。逆に、銀の量が多すぎると、使用量に見合った活性の向上が見られないことや、触媒の製造時や反応の過程で銀粒子がシンタリングを起こし、反応において有効な銀の表面積が相対的に小さくなってしまうことがあり、この場合も充分な活性が得られないことがある。
[Silver particles]
The silver component that is the active species of the selective hydrogenation catalyst of the present invention is silver and / or silver oxide. The amount of the silver component supported is not particularly limited, but is preferably 1.0 μmol to 5 mmol, particularly preferably 10 μmol to 3 mmol, and most preferably 100 μmol to 2 mmol in terms of silver element per 1 g of the alumina support. The silver equivalent amount of the silver component with respect to alumina when viewed in terms of weight ratio is preferably 10 wt% or less, and particularly preferably 5 wt%. If the amount of the silver component is too small, sufficient activity may not be obtained and the reaction may take time. On the other hand, if the amount of silver is too large, there is no improvement in activity commensurate with the amount used, or silver particles are sintered during the production of the catalyst or during the reaction, and the effective silver surface area in the reaction. May become relatively small, and in this case, sufficient activity may not be obtained.

また、本発明の選択的水素化触媒において、担体に担持される銀成分粒子の平均粒子径は、0.5〜3nmであり、好ましくは、0.5〜2nmである。担持された銀成分の粒子径は、広域X線吸収微細構造(EXAFS)あるいは粉末X線回折により求めることができる。具体的には、AgのK殻のX線吸収微細構造(X-ray absorption fine structure:XAFS)をSPring−8、BL−01B1にて室温で測定し、そこからEXAFSのAg−Ag配位数を得、下記文献中の計算式より粒径を見積もることにより求めることができる。
* A. Jentys, Phys. Chem. Chem. Phys., 1999, vol. 1, p. 4059.
In the selective hydrogenation catalyst of the present invention, the average particle size of the silver component particles supported on the support is 0.5 to 3 nm, preferably 0.5 to 2 nm. The particle diameter of the supported silver component can be determined by a wide-area X-ray absorption fine structure (EXAFS) or powder X-ray diffraction. Specifically, the X-ray absorption fine structure (XAFS) of the K shell of Ag is measured at room temperature with SPring-8 and BL-01B1, and from there, the Ag-Ag coordination number of EXAFS Can be obtained by estimating the particle diameter from the calculation formula in the following document * .
* A. Jentys, Phys. Chem. Chem. Phys., 1999, vol. 1, p. 4059.

この銀成分の粒子が小さすぎると、反応に使用した際に触媒の活性が早く低下してしまうことがある。逆に平均粒子径が大きすぎると銀粒子の質量当たりの比表面積値が小さくなり活性が低下し水素化が促進されないことがある。   If the silver component particles are too small, the activity of the catalyst may decrease quickly when used in the reaction. On the other hand, if the average particle size is too large, the specific surface area value per mass of the silver particles becomes small, the activity is lowered, and hydrogenation may not be promoted.

また、本発明の選択的水素化触媒において使用される銀成分は金属銀であることが好ましいが、必ずしも銀成分の全てが金属銀である必要はなく、一部が酸化銀として存在してもよい。例えば、後述する製法や再生方法においても焼成(か焼;calcination)して酸化した後、還元処理を施しているが、必ずしも銀成分の全てが金属銀になっているわけではない。このように、酸化銀と金属銀が混在する場合、金属銀の含有量が多い事が望ましいことはいうまでもないが、その金属銀含量は、実施において求められる活性に応じて適宜設定すればよい。以下、選択的水素化触媒の他、その原料となる銀成分が担持されたアルミナも含め単に銀触媒ということがあるが、ここでの銀は金属銀のみからなるものに限定されるものではない。   Further, the silver component used in the selective hydrogenation catalyst of the present invention is preferably metallic silver, but it is not always necessary that all of the silver component is metallic silver, even if part of it is present as silver oxide. Good. For example, in the manufacturing method and the regenerating method described later, the reduction treatment is performed after calcination and oxidation, but the silver component is not necessarily all metallic silver. Thus, when silver oxide and metallic silver are mixed, it is needless to say that it is desirable that the content of metallic silver is high, but the metallic silver content can be appropriately set according to the activity required in practice. Good. Hereinafter, in addition to the selective hydrogenation catalyst, there may be referred to simply as a silver catalyst including alumina carrying a silver component as a raw material, but the silver here is not limited to a metal silver only. .

[ 製 法 ]
本発明の銀触媒の製造は、例えば、銀化合物を溶媒に溶解し、当該溶液中に担体としてのアルミナを投入し、銀化合物を吸着または含浸せしめることが必要である。上記銀化合物としては、触媒調製工程に使用する溶媒に可溶性であれば特に限定されず、例えば、硝酸銀、酢酸銀、過塩素酸銀などや、ビス(2,2'−ビピリジン)銀(I)硝酸塩、ビス(1,10−ファナントロリン)銀(I)過塩素酸塩やテトラキス(トリフェニルホスフィン)銀(I)硝酸塩などが挙げられ、これらのうち硝酸銀が特に好ましい。上記銀化合物のうち、硝酸銀、亜硝酸銀、酢酸銀、過塩素酸銀のような水溶性の銀化合物を利用する場合には、水を溶媒として用いることができる。また、銀化合物として、ビス(2,2'−ビピリジン)銀(I)硝酸塩、ビス(1,10−ファナントロリン)銀(I)過塩素酸塩やテトラキス(トリフェニルホスフィン)銀(I)硝酸塩などの非水溶性のものを使用する場合には、有機溶媒を溶媒として用いることができる。
[Production method]
The production of the silver catalyst of the present invention requires, for example, that a silver compound is dissolved in a solvent, alumina as a carrier is introduced into the solution, and the silver compound is adsorbed or impregnated. The silver compound is not particularly limited as long as it is soluble in the solvent used in the catalyst preparation step. For example, silver nitrate, silver acetate, silver perchlorate, bis (2,2′-bipyridine) silver (I) Examples thereof include nitrate, bis (1,10-phananthroline) silver (I) perchlorate, tetrakis (triphenylphosphine) silver (I) nitrate, and the like, among which silver nitrate is particularly preferable. Among the above silver compounds, when a water-soluble silver compound such as silver nitrate, silver nitrite, silver acetate, or silver perchlorate is used, water can be used as a solvent. Further, as a silver compound, bis (2,2′-bipyridine) silver (I) nitrate, bis (1,10-phananthroline) silver (I) perchlorate and tetrakis (triphenylphosphine) silver (I) nitrate In the case of using a water-insoluble one such as an organic solvent, an organic solvent can be used as a solvent.

担体に対する銀化合物溶液の含浸量は担体全体に銀化合物溶液が行き渡る量であることが好ましく、吸水率のほぼ100%、またはそれ以上となるように調整することが好ましい。このように含浸させることで、担体に対して銀製分を均一に担持させることができる。   The amount of the silver compound solution impregnated with respect to the carrier is preferably an amount that allows the silver compound solution to spread over the entire carrier, and is preferably adjusted to be approximately 100% or more of the water absorption rate. By impregnating in this way, the silver component can be uniformly supported on the carrier.

このように担体の吸水率のほぼ100%となるように銀化合物水溶液を担体に含浸させる場合、銀化合物水溶液の濃度は目的とする銀成分の担持量を想定した濃度に調整されていることが望ましく、吸水率の100%以上の銀化合物溶液を含浸させる場合も同様である。なお、吸水率の100%以上の銀化合物溶液を含浸させる場合、担体に銀化合物溶液が均一に行き渡るよう、適宜溶媒の蒸発処理などを施すことがある。 As described above, when the carrier is impregnated with the silver compound aqueous solution so that the water absorption rate of the carrier is almost 100%, the concentration of the silver compound aqueous solution is adjusted to a concentration that assumes the supported amount of the silver component. Desirably, the same applies when impregnating a silver compound solution having a water absorption rate of 100% or more. In addition, when impregnating a silver compound solution having a water absorption rate of 100% or more, a solvent evaporation treatment or the like may be appropriately performed so that the silver compound solution is uniformly distributed on the carrier.

こうして銀化合物を吸着または含浸などの方法で担体に担持したアルミナは、次いで、乾燥し、焼成して酸化した後、焼成により酸化状態となった銀成分に還元処理を施すことで本発明の銀触媒を得ることができる。このような、乾燥、焼成および還元処理の条件は特に限定されるものでは無いが、乾燥は水を溶媒として使用した場合は100〜200℃の範囲で乾燥すれば良く、必要に応じて減圧処理や乾燥空気流を使用してもよい。   The alumina thus supported on the support by adsorption or impregnation of the silver compound is then dried, calcined and oxidized, and then subjected to a reduction treatment on the silver component that has been oxidized by calcining. A catalyst can be obtained. The conditions for such drying, firing and reduction treatment are not particularly limited, but drying may be performed in the range of 100 to 200 ° C. when water is used as a solvent, and reduced pressure treatment as necessary. Or a dry air stream may be used.

また、銀触媒の製造における焼成温度は500〜1000℃であることが好ましく、500〜800℃であることがより好ましい。加熱温度が高すぎる場合、アルミナの相転移に伴い銀粒子のシンタリングが起こりはじめ、活性が低下することがあり望ましくない。逆に、加熱温度が低すぎる場合、表面に吸着した有機物の燃焼除去が不完全になり、触媒能力を完全に付与することができないことがあり望ましくない。   Moreover, it is preferable that the calcination temperature in manufacture of a silver catalyst is 500-1000 degreeC, and it is more preferable that it is 500-800 degreeC. When the heating temperature is too high, sintering of silver particles starts to occur with the phase transition of alumina, and the activity may be lowered. On the other hand, when the heating temperature is too low, combustion removal of the organic matter adsorbed on the surface becomes incomplete, and it may not be possible to provide the catalyst ability completely.

焼成時の雰囲気は、無酸素状態(酸素0vol%)では、本発明の選択的水素化触媒を得ることはできないので、酸素量が概ね20vol%程度であることが好ましい。酸素濃度が低すぎると、焼成時に金属状態のAgが形成され、後述する還元処理後の粒径が大きくなる場合があるため好ましくない。   Since the selective hydrogenation catalyst of the present invention cannot be obtained in an oxygen-free state (oxygen 0 vol%), the amount of oxygen is preferably about 20 vol%. If the oxygen concentration is too low, Ag in a metallic state is formed at the time of firing, and the particle size after the reduction treatment described later may increase, which is not preferable.

更に、このように焼成された銀触媒は、更に還元剤を添加され、加熱されることで還元され、金属銀を含む銀成分が高度に分散された銀触媒になる。本発明の銀触媒の製造は、湿式、乾式いずれも採用できるが、乾式であることが望ましい。乾式で還元する場合にはガス状水素など気体の還元剤を用いて行うことが望ましいが、この際、ガス状水素等の気体還元剤を窒素等の不活性ガスで希釈して使用することも可能である。特にガス状水素(水素ガス)を使うことで本発明の銀触媒の製造において効率的な還元が行われ、銀成分中の金属成分の量を多くできる。一方、湿式で還元する場合の還元剤には、メタノール、ホルムアルデヒド、蟻酸など液状の還元剤を使用することができる。   Furthermore, the silver catalyst thus calcined is further reduced by being added with a reducing agent and heated to become a silver catalyst in which a silver component containing metallic silver is highly dispersed. The silver catalyst of the present invention can be produced by either a wet method or a dry method, but is preferably a dry method. In the case of dry reduction, it is desirable to use a gaseous reducing agent such as gaseous hydrogen. At this time, a gaseous reducing agent such as gaseous hydrogen may be diluted with an inert gas such as nitrogen. Is possible. In particular, by using gaseous hydrogen (hydrogen gas), efficient reduction is performed in the production of the silver catalyst of the present invention, and the amount of the metal component in the silver component can be increased. On the other hand, a liquid reducing agent such as methanol, formaldehyde, formic acid or the like can be used as a reducing agent in the case of reducing by wet.

上記の還元処理における加熱温度は300〜900℃であることが好ましく、400〜800℃がより好ましい。加熱温度が低すぎると、還元が充分に出来ない事があり、逆に高すぎると銀成分がシンタリングしてしまい、質量当たりの比表面積値が小さくなり活性が低下し水素化が促進されないことがある。   It is preferable that the heating temperature in said reduction process is 300-900 degreeC, and 400-800 degreeC is more preferable. If the heating temperature is too low, the reduction may not be sufficiently performed. Conversely, if the heating temperature is too high, the silver component will sinter, the specific surface area value per mass will decrease, the activity will decrease, and hydrogenation will not be promoted. There is.

なお、上記した酸化、還元処理における加熱の温度によって、銀成分の粒子径の制御も可能である。例えば、還元処理における加熱温度が低い場合は、銀成分の粒子径を比較的小さくすることができ、還元処理における加熱温度が高い場合には、銀成分の粒子径を比較的大きくすることができる。また、このような還元処理における加熱温度と銀粒子の粒径の関係は、銀成分の量の変化にも影響を受ける。多くの場合、銀成分の量が多いと粒径が大きくなる傾向にあり、銀成分の量が少ないと粒径が小さくなる傾向がある。   The particle diameter of the silver component can also be controlled by the heating temperature in the above oxidation and reduction treatment. For example, when the heating temperature in the reduction treatment is low, the particle size of the silver component can be made relatively small, and when the heating temperature in the reduction treatment is high, the particle size of the silver component can be made relatively large. . In addition, the relationship between the heating temperature and the particle size of silver particles in such a reduction treatment is also affected by changes in the amount of silver component. In many cases, when the amount of the silver component is large, the particle size tends to be large, and when the amount of the silver component is small, the particle size tends to be small.

本発明の選択的水素化触媒調製のための好ましい条件としては以下の組み合わせが挙げられる。
・アルミナに対するAgの量が10wt%以下。
・焼成温度が500〜1000℃(現実的には600〜800℃)。
・焼成時の酸素濃度が20wt%以上(実際には20wt%で充分)。
・還元雰囲気が水素
・還元温度が300〜900℃
Preferred conditions for preparing the selective hydrogenation catalyst of the present invention include the following combinations.
-The amount of Ag with respect to alumina is 10 wt% or less.
The firing temperature is 500 to 1000 ° C. (practically 600 to 800 ° C.).
-The oxygen concentration at the time of firing is 20 wt% or more (actually, 20 wt% is sufficient).
・ Reducing atmosphere is hydrogen ・ Reducing temperature is 300 ~ 900 ℃

前述のように、本発明の選択的水素化触媒では、担持された銀成分の平均粒子径が重要であるので、実験的に還元処理温度と銀成分の平均粒子径の関係あるいは銀成分の量と銀成分の平均粒子径の関係を求め、これを基に希望する触媒活性を有する選択的水素化触媒を調製すればよい。以上のような還元時の加熱温度と粒子径の関係等が生じる理由は定かではないが、本発明者らの検証したところでは、還元処理における加熱温度による銀成分の粒子径の変化はシリカなど他の担体では見られない、アルミナと銀成分との間で生じる特異な相互作用であった。   As described above, in the selective hydrogenation catalyst of the present invention, since the average particle size of the supported silver component is important, the relationship between the reduction treatment temperature and the average particle size of the silver component or the amount of the silver component is experimentally determined. The selective hydrogenation catalyst having the desired catalytic activity may be prepared based on the relationship between the average particle size of the silver component and the silver component. The reason why the relationship between the heating temperature and the particle size during the reduction as described above is not clear, but the present inventors have verified that the change in the particle size of the silver component due to the heating temperature in the reduction treatment is silica or the like. It was a unique interaction that occurred between the alumina and silver components that was not seen with other carriers.

[ 選択的水素化反応 ]
以上のようにして調製された本発明の選択的水素化触媒は、芳香族ニトロ化合物のニトロ基の選択的水素化に利用することができる。
[Selective hydrogenation reaction]
The selective hydrogenation catalyst of the present invention prepared as described above can be used for selective hydrogenation of a nitro group of an aromatic nitro compound.

上記の選択的水素化反応は、加熱条件下、有機溶剤中で、芳香族ニトロ化合物、前記選択的水素化触媒および水素ガスとを混合させることにより行うことができる。この選択水素化反応に用いる有機溶剤としては、特に制限されないが、溶剤として触媒の被毒が少なく、添加率を維持できるものの中から選択することができ、好ましくは、テトラヒドロフラン、メタノール、エタノール、トルエンなどの溶媒またはこれらの組み合わせが挙げられる。   The selective hydrogenation reaction can be carried out by mixing an aromatic nitro compound, the selective hydrogenation catalyst, and hydrogen gas in an organic solvent under heating conditions. The organic solvent used in this selective hydrogenation reaction is not particularly limited, but can be selected from those which can be used as a solvent with little catalyst poisoning and can maintain the addition rate, preferably tetrahydrofuran, methanol, ethanol, toluene. Or a combination thereof.

本発明の選択的水素化方法は特に限定するものではないが、水素の存在は必須である。水素は遊離の状態の水素であり、通常、水素ガスとして反応中にあるいは反応に先んじて反応系に供給すればよい。例えば、攪拌下の反応液の上部気相部に供給してもよいし、通気してもよい。水素は例えば窒素などの不活性気体との混合ガスとして供給してもよい。   The selective hydrogenation method of the present invention is not particularly limited, but the presence of hydrogen is essential. Hydrogen is hydrogen in a free state, and is usually supplied to the reaction system during the reaction or prior to the reaction as hydrogen gas. For example, it may be supplied to the upper gas phase portion of the reaction liquid under stirring or aerated. Hydrogen may be supplied as a mixed gas with an inert gas such as nitrogen.

供給される水素の圧力は特に限定されるものではないが、水素分圧として0.005〜30Maが好適であり、0.05〜10MPaが特に好適である。この水素化反応は、通常、湿式にて水素ガス雰囲気中で行われる。また、反応温度は120〜200℃の温度範囲が好適である。   Although the pressure of the hydrogen to be supplied is not particularly limited, 0.005 to 30 Ma is preferable as the hydrogen partial pressure, and 0.05 to 10 MPa is particularly preferable. This hydrogenation reaction is usually carried out in a hydrogen gas atmosphere in a wet manner. The reaction temperature is preferably in the temperature range of 120 to 200 ° C.

更に、上記選択的水素化方法に使用される選択的水素化触媒の量は、反応に使用する芳香族ニトロ化合物に対して、当該触媒に担持される銀成分を基準に、金属銀換算で0.01〜20モル%の範囲の量で使用されることが好ましく、0.1〜10モル%の範囲で使用されることがより好ましく、0.5〜5モル%の範囲で使用されることが最も好ましい。選択的水素化触媒の使用量が少なすぎると、充分な活性が得られないことがあり、反応にも時間がかかることがある。一方、選択的水素化触媒の銀の量が多すぎると、銀成分の分散度が低下して活性が低下したり、また使用量に見合った活性の向上が見られないことがある。   Furthermore, the amount of the selective hydrogenation catalyst used in the selective hydrogenation method is 0 in terms of metallic silver based on the silver component supported on the catalyst with respect to the aromatic nitro compound used in the reaction. It is preferably used in an amount in the range of 0.01 to 20 mol%, more preferably in the range of 0.1 to 10 mol%, and in the range of 0.5 to 5 mol%. Is most preferred. If the amount of the selective hydrogenation catalyst used is too small, sufficient activity may not be obtained and the reaction may take time. On the other hand, if the amount of silver in the selective hydrogenation catalyst is too large, the dispersity of the silver component may be reduced to lower the activity, or the activity may not be improved in accordance with the amount used.

上記選択的水素化反応は、芳香族ニトロ化合物の芳香環または複素環に結合したニトロ基が水素化され、アミノ基となるまで行われる。その反応時間は、触媒の量とも相関するが、一般的には、0.1ないし48時間程度であり、好ましくは、0.5ないし8時間程度である。   The selective hydrogenation reaction is performed until the nitro group bonded to the aromatic ring or heterocyclic ring of the aromatic nitro compound is hydrogenated to an amino group. Although the reaction time correlates with the amount of the catalyst, it is generally about 0.1 to 48 hours, and preferably about 0.5 to 8 hours.

このようにすることにより、芳香族ニトロ化合物中のニトロ基は水素化されるが、それ以外の基、例えば、芳香環または複素環に結合した炭素−炭素二重結合、ハロゲン原子、ケトン性カルボニル基、カルボン酸エステル基、アミド性カルボニル基、ニトリル基等は水素化されず、ニトロ基の選択的水素化が可能となる。なお、使用した選択的水素化触媒は、反応終了後、ろ過等の簡便な方法で生成物を含む溶液から容易に分離し、繰り返し使用することができる。   By doing so, the nitro group in the aromatic nitro compound is hydrogenated, but other groups such as a carbon-carbon double bond, a halogen atom, a ketonic carbonyl bonded to an aromatic ring or a heterocyclic ring. Groups, carboxylic acid ester groups, amido carbonyl groups, nitrile groups, and the like are not hydrogenated, allowing selective hydrogenation of nitro groups. The selective hydrogenation catalyst used can be easily separated from the solution containing the product by a simple method such as filtration after the completion of the reaction, and can be used repeatedly.

[ 触媒の再生 ]
上記のように反応系から分離した選択的水素化触媒は、再び選択的水素化反応に繰返し使用されるが、繰返し使用することで徐々に失活する。本発明の選択的水素化触媒の大きな特徴は、このように失活した場合も比較的簡単な方法で再生させることができ、再生された触媒も失活前とほぼ同等の性能を発揮することができることである。
[Catalyst regeneration]
The selective hydrogenation catalyst separated from the reaction system as described above is repeatedly used for the selective hydrogenation reaction again, but is gradually deactivated by repeated use. The main feature of the selective hydrogenation catalyst of the present invention is that it can be regenerated by a relatively simple method even when it is deactivated in this way, and the regenerated catalyst also exhibits almost the same performance as before deactivation. It is possible to do.

この、失活した選択的水素化触媒を再生は、生成物を含む溶液から分離した触媒を水と有機溶剤の混合溶媒で洗浄し、乾燥後に酸化雰囲気で焼成し、続いて還元処理することによりおこなわれる。   This deactivated selective hydrogenation catalyst is regenerated by washing the catalyst separated from the product-containing solution with a mixed solvent of water and an organic solvent, baking it in an oxidizing atmosphere after drying, and subsequently reducing the catalyst. It is carried out.

洗浄に使用される混合溶媒は適宜選択されるが、具体的には蒸留水とエタノール等の有機溶剤の混合溶媒が使用でき、それらの好ましい混合割合としては、有機溶剤と蒸留水とが体積比1:1のものが挙げられる。   The mixed solvent used for washing is appropriately selected. Specifically, a mixed solvent of distilled water and an organic solvent such as ethanol can be used, and a preferable mixing ratio thereof is a volume ratio of the organic solvent and distilled water. 1: 1 are mentioned.

洗浄後、乾燥する温度も適宜設定されるが、概ね100℃前後であることが望ましい。
乾燥された使用済み触媒の焼成温度は500℃〜1000℃であることが好ましく、500℃〜800℃であることがより好ましい。焼成温度が高すぎる場合、アルミナの相転移に伴い銀粒子のシンタリングが起こりはじめ、活性が低下することがあり望ましくない。また、焼成温度が低すぎる場合、表面に吸着した有機物の燃焼除去が不完全になり、触媒を完全に再生することができないことがあり望ましくない。
The temperature for drying after washing is also set as appropriate, but is preferably around 100 ° C.
The calcination temperature of the dried used catalyst is preferably 500 ° C to 1000 ° C, and more preferably 500 ° C to 800 ° C. When the calcination temperature is too high, sintering of silver particles begins to occur with the phase transition of alumina, and the activity may be lowered. Moreover, when the calcination temperature is too low, combustion removal of the organic matter adsorbed on the surface becomes incomplete, and the catalyst cannot be completely regenerated, which is not desirable.

焼成時の雰囲気は、無酸素状態(酸素0vol%)では、本発明の選択的水素化触媒を得ることはできないので、酸素量が概ね20vol%程度であることが好ましい。酸素濃度が低すぎると、焼成時に金属状態のAgが形成され、後述する還元処理後の粒径が大きくなる場合があるため好ましくない。   Since the selective hydrogenation catalyst of the present invention cannot be obtained in an oxygen-free state (oxygen 0 vol%), the amount of oxygen is preferably about 20 vol%. If the oxygen concentration is too low, Ag in a metallic state is formed at the time of firing, and the particle size after the reduction treatment described later may increase, which is not preferable.

焼成された触媒は、銀粒子の表面が酸化されていることがあるため還元処理を行う。還元処理についても適宜選択可能であるが、還元剤として水素ガスを使用し、300℃で5分程度還元することにより還元することも、また、前記製造時と同様の条件で還元することもできる。   The calcined catalyst is subjected to a reduction treatment because the surface of the silver particles may be oxidized. Although reduction treatment can be selected as appropriate, it can be reduced by using hydrogen gas as a reducing agent at about 300 ° C. for about 5 minutes, or can be reduced under the same conditions as in the above production. .

すなわち、還元方法は湿式、乾式いずれも採用できるが、乾式であることが望ましい。乾式で還元する場合にはガス状水素など気体の還元剤を用いて行うことが望ましいが、この際、ガス状水素等の気体還元剤を窒素等の不活性ガスで希釈して使用することも可能である。特にガス状水素(水素ガス)を使うことで本発明の銀触媒の製造において効率的な還元が行われ、銀成分中の金属成分の量を多くできる。一方、湿式で還元する場合の還元剤には、メタノール、ホルムアルデヒド、蟻酸など液状の還元剤を使用することができる。   That is, the reduction method can be either wet or dry, but is preferably dry. In the case of dry reduction, it is desirable to use a gaseous reducing agent such as gaseous hydrogen. At this time, a gaseous reducing agent such as gaseous hydrogen may be diluted with an inert gas such as nitrogen. Is possible. In particular, by using gaseous hydrogen (hydrogen gas), efficient reduction is performed in the production of the silver catalyst of the present invention, and the amount of the metal component in the silver component can be increased. On the other hand, a liquid reducing agent such as methanol, formaldehyde, formic acid or the like can be used as a reducing agent in the case of reducing by wet.

上記の還元処理における加熱温度は300〜900℃であることが好ましく、400〜800℃がより好ましい。加熱温度が低すぎると、還元が充分に出来ない事があり、逆に高すぎると銀成分がシンタリングしてしまい、質量当たりの比表面積値が小さくなり活性が低下し水素化が促進されないことがある。   It is preferable that the heating temperature in said reduction process is 300-900 degreeC, and 400-800 degreeC is more preferable. If the heating temperature is too low, the reduction may not be sufficiently performed. Conversely, if the heating temperature is too high, the silver component will sinter, the specific surface area value per mass will decrease, the activity will decrease, and hydrogenation will not be promoted. There is.

なお、ここでも前述の選択的水素化触媒の製造と同様、還元処理における加熱温度の制御によって銀成分の粒子径の制御が可能である。反応に使用した結果や、再生処理の過程で銀成分粒子が肥大化した場合でも、焼成による酸化あるいは水素を還元剤とした加熱還元を経ることで選択的水素化触媒上の銀成分の粒子径を微細に制御することができる。   In this case as well, the particle diameter of the silver component can be controlled by controlling the heating temperature in the reduction treatment, as in the production of the selective hydrogenation catalyst described above. The particle size of the silver component on the selective hydrogenation catalyst can be obtained through oxidation in the firing or heat reduction using hydrogen as a reducing agent, even if the silver component particles are enlarged in the process of regeneration or in the process of regeneration. Can be finely controlled.

このように再生された選択的水素化触媒は、再び前述同様の水素化に使用することができ、芳香族ニトロ化合物の選択的水素化を経済的に有利に行うことができる。   The selective hydrogenation catalyst regenerated in this way can be used again for the same hydrogenation as described above, and the selective hydrogenation of aromatic nitro compounds can be carried out economically advantageously.

以下に本発明の実施例、比較例および参考例を示し、本発明を更に詳しく説明するが、本発明はこれら実施例等に何ら制約されるものではない。   EXAMPLES Examples, comparative examples, and reference examples of the present invention will be described below to describe the present invention in more detail. However, the present invention is not limited to these examples.

実 施 例 1
銀を担持した触媒の調製:
下記方法により、表1に示す銀含有量および金属平均粒子径の銀を担持した銀触媒を調製した。
Example 1
Preparation of silver supported catalyst:
The silver catalyst which carry | supported silver of silver content and metal average particle diameter shown in Table 1 by the following method was prepared.

すなわち、触媒1ないし5については、担体としてγ-アルミナ(Sasol製アルミナ「CatapalB」)を1000℃にて3時間焼成することによって得たθ-アルミナ粉末を用い、これを0.5Mの硝酸銀水溶液に浸漬した。その後、減圧下80℃で3時間乾燥し、表1に示す温度で3時間焼成した。更に水素気流下、表1に示した温度で10分間処理することにより、アルミナ担持銀触媒として触媒1ないし5を得た。   That is, for catalysts 1 to 5, θ-alumina powder obtained by calcining γ-alumina (alumina “Catapal B” manufactured by Sasol) at 1000 ° C. for 3 hours was used as a carrier, and this was used as a 0.5 M silver nitrate aqueous solution. Soaked in. Then, it dried at 80 degreeC under pressure reduction for 3 hours, and baked at the temperature shown in Table 1 for 3 hours. Furthermore, the catalyst 1 thru | or 5 was obtained as an alumina carrying | support silver catalyst by processing for 10 minutes at the temperature shown in Table 1 under hydrogen stream.

一方触媒9および10については、担体であるセリア、マグネシアとして、触媒学会が提供する参照触媒(それぞれJRC-CEO-1、JRC-MGO-1)を使用し、触媒11については、担体であるシリカとして富士シリシア製「Q−15」を使用した。また、触媒6ないし8については、担体であるジルコニア、酸化スズ、酸化タングステンとして、それぞれジルコニウムオキシ硝酸塩・2水和物、四塩化スズ・6水和物、パラタングステン酸アンモニウム塩を、蒸留水中にて水酸化アンモニウム水溶液(1.0mol/L)を加えることによって生じる沈殿を蒸留水で3回洗浄し、さらに100℃で乾燥することによって得たものを使用した。   On the other hand, for catalysts 9 and 10, reference catalysts (JRC-CEO-1 and JRC-MGO-1) provided by the Catalytic Society are used as the supports ceria and magnesia, respectively, and for catalyst 11 the silica as the support. “Q-15” manufactured by Fuji Silysia was used. For catalysts 6 to 8, zirconium oxynitrate dihydrate, tin tetrachloride hexahydrate, and ammonium paratungstate were added to distilled water as zirconia, tin oxide, and tungsten oxide, respectively. Then, a precipitate obtained by adding an aqueous ammonium hydroxide solution (1.0 mol / L) was washed three times with distilled water, and further dried at 100 ° C. was used.

これらの担体を、0.5Mの硝酸銀水溶液に浸漬した。その後、減圧下80℃で3時間乾燥し、表1に示す温度で3時間焼成した。更に、水素気流下、表1に示した温度で10分間処理することにより、触媒6ないし11を得た。   These carriers were immersed in a 0.5 M aqueous silver nitrate solution. Then, it dried at 80 degreeC under pressure reduction for 3 hours, and baked at the temperature shown in Table 1 for 3 hours. Furthermore, the catalyst 6 thru | or 11 was obtained by processing for 10 minutes at the temperature shown in Table 1 under hydrogen stream.

以上、各触媒の担体、銀平均粒子径、銀含有量、焼成温度および還元温度をまとめて表1に示した、なお、担持された銀の平均粒子径は、EXAFSにより求めた。   The carrier, silver average particle size, silver content, calcination temperature and reduction temperature of each catalyst are summarized in Table 1 above. The average particle size of the supported silver was determined by EXAFS.

Figure 2011036748
Figure 2011036748

実 施 例 1
銀平均粒子径が0.7nmである銀担持アルミナ粉末触媒(触媒1)を用いた
4−ニトロスチレンの水素化反応:
内容積30ccのオートクレーブに、4−ニトロスチレン0.30g(2mmol)、触媒1 0.5g(触媒中の銀含有量1wt%、銀使用量は基質に対し2mol%)、および溶媒としてテトラヒドロフラン15mlを取り、さらに攪拌子を入れ密閉した。水素により反応器内をパージした後、160℃まで加温し、さらに水素圧3MPaまで加圧し、1時間反応した。攪拌はマグネチックスターラーを用いた。
Example 1
Hydrogenation reaction of 4-nitrostyrene using a silver supported alumina powder catalyst (catalyst 1) having an average silver particle diameter of 0.7 nm:
In an autoclave with an internal volume of 30 cc, 0.30 g (2 mmol) of 4-nitrostyrene, 0.5 g of catalyst 1 (silver content in the catalyst is 1 wt%, silver usage is 2 mol% with respect to the substrate), and 15 ml of tetrahydrofuran as a solvent. The mixture was further sealed with a stirring bar. After purging the inside of the reactor with hydrogen, the temperature was raised to 160 ° C., the pressure was further increased to 3 MPa, and the reaction was performed for 1 hour. A magnetic stirrer was used for stirring.

生成物は、株式会社島津製作所製ガスクロマトグラフ質量分析計GCMS−QP5000を用いて同定し、反応後の生成物の収率は、n−ドデカンを内部標準物質としてガスクロマトグラフィーにて決定した。この結果、原料である4−ニトロスチレンの転化率は99%で、目的生成物である4−アミノスチレンの選択率は88%であり、副生成物である4−エチルアニリンの選択率は3.9%であった。   The product was identified by using a gas chromatograph mass spectrometer GCMS-QP5000 manufactured by Shimadzu Corporation, and the yield of the product after the reaction was determined by gas chromatography using n-dodecane as an internal standard substance. As a result, the conversion of 4-nitrostyrene as a raw material was 99%, the selectivity of 4-aminostyrene as a target product was 88%, and the selectivity of 4-ethylaniline as a by-product was 3%. 0.9%.

実 施 例 2
銀平均粒子径が0.9nmである銀担持アルミナ粉末触媒(触媒2)を用いた
4−ニトロスチレンの水素化反応:
実施例1において、銀平均粒子径が0.7nmの触媒1の代わりに、銀平均粒子径が0.9nmである触媒2 0.1g(触媒中の銀含有量5wt%、銀使用量は基質に対し2mol%)を用いた以外は実施例1と同様にして、4−ニトロスチレンの水素化を行った。反応の結果、原料である4−ニトロスチレンの転化率は100%で、目的生成物である4−アミノスチレンの選択率は96%であり、副生成物である4−エチルアニリンの選択率は3.0%であった。
Example 2
Hydrogenation reaction of 4-nitrostyrene using a silver-supported alumina powder catalyst (catalyst 2) having an average silver particle size of 0.9 nm:
In Example 1, instead of catalyst 1 having an average silver particle size of 0.7 nm, 0.1 g of catalyst 2 having an average silver particle size of 0.9 nm (the silver content in the catalyst was 5 wt%, the amount of silver used was the substrate) 4-nitrostyrene was hydrogenated in the same manner as in Example 1 except that 2 mol%) was used. As a result of the reaction, the conversion rate of 4-nitrostyrene as a raw material was 100%, the selectivity of 4-aminostyrene as a target product was 96%, and the selectivity of 4-ethylaniline as a by-product was It was 3.0%.

実 施 例 3
銀平均粒子径が1.1nmである銀担持アルミナ粉末触媒(触媒3)を用いた
4−ニトロスチレンの水素化反応:
実施例1において、銀平均粒子径が0.7nmの触媒1の代わりに、銀平均粒子径が1.1nmである触媒3 0.1g(触媒中の銀含有量5wt%、銀使用量は基質に対し2mol%)を用いた以外は実施例1と同様にして、4−ニトロスチレンの水素化を行った。反応の結果、原料である4−ニトロスチレンの転化率は100%で、目的生成物である4−アミノスチレンの選択率は95%であり、副生成物である4−エチルアニリンの選択率は2.9%であった。
Example 3
Hydrogenation of 4-nitrostyrene using a silver supported alumina powder catalyst (catalyst 3) having an average silver particle diameter of 1.1 nm:
In Example 1, instead of the catalyst 1 having a silver average particle diameter of 0.7 nm, 0.1 g of a catalyst 3 having a silver average particle diameter of 1.1 nm (the silver content in the catalyst is 5 wt%, the amount of silver used is the substrate) 4-nitrostyrene was hydrogenated in the same manner as in Example 1 except that 2 mol%) was used. As a result of the reaction, the conversion rate of 4-nitrostyrene as a raw material was 100%, the selectivity of 4-aminostyrene as a target product was 95%, and the selectivity of 4-ethylaniline as a by-product was It was 2.9%.

比 較 例 1
銀平均粒子径が3.4nmである銀担持アルミナ粉末触媒(触媒4)を用いた
4−ニトロスチレンの水素化反応:
実施例1において、銀平均粒子径が0.7nmの触媒1の代わりに、銀平均粒子径が3.4nmである触媒4 0.1g(触媒中の銀含有量5wt%、銀使用量は基質に対し2mol%)を用いた以外は実施例1と同様にして、4−ニトロスチレンの水素化を行った。反応の結果、原料である4−ニトロスチレンの転化率は31%で、目的生成物である4−アミノスチレンの選択率は73%であり、副生成物である4−エチルアニリンの選択率は2.6%であった。
Comparative Example 1
Hydrogenation reaction of 4-nitrostyrene using a silver supported alumina powder catalyst (catalyst 4) having an average silver particle diameter of 3.4 nm:
In Example 1, instead of catalyst 1 having an average silver particle size of 0.7 nm, 0.1 g of catalyst 4 having an average silver particle size of 3.4 nm (the silver content in the catalyst was 5 wt%, the amount of silver used was the substrate) 4-nitrostyrene was hydrogenated in the same manner as in Example 1 except that 2 mol%) was used. As a result of the reaction, the conversion of 4-nitrostyrene as a raw material was 31%, the selectivity of 4-aminostyrene as a target product was 73%, and the selectivity of 4-ethylaniline as a by-product was It was 2.6%.

比 較 例 2
銀平均粒子径が25nmである銀担持アルミナ粉末触媒(触媒5)を用いた4−ニ
トロスチレンの水素化反応:
実施例1において、銀平均粒子径が0.7nmの触媒1の代わりに、銀平均粒子径が25nmである触媒5 0.1g(触媒中の銀含有量5wt%、銀使用量は基質に対し2mol%)を用いた以外は実施例1と同様にして、4−ニトロスチレンの水素化を行った。反応の結果、原料である4−ニトロスチレンの転化率は31%であったが、予想される水素化生成物である4−アミノスチレンおよび4−エチルアニリンはいずれも全く生成しなかった。
Comparative Example 2
Hydrogenation reaction of 4-nitrostyrene using a silver supported alumina powder catalyst (catalyst 5) having an average silver particle diameter of 25 nm:
In Example 1, instead of catalyst 1 having an average silver particle size of 0.7 nm, 0.1 g of catalyst 5 having an average silver particle size of 25 nm (silver content in the catalyst is 5 wt%, the amount of silver used is based on the substrate) 4-Nitrostyrene was hydrogenated in the same manner as in Example 1 except that 2 mol%) was used. As a result of the reaction, the conversion of 4-nitrostyrene as a raw material was 31%, but 4-aminostyrene and 4-ethylaniline as expected hydrogenation products were not produced at all.

比 較 例 3
銀平均粒子径2.6nmである銀担持酸化タングステン粉末触媒(触媒6)
を用いた4−ニトロスチレンの水素化反応:
実施例1において、銀平均粒子径が0.7nmの銀担持アルミナ粉末触媒(触媒1)の代わりに、銀平均粒子径が2.6nmである触媒6 0.1g(触媒中の銀含有量5wt%、銀使用量は基質に対し2mol%)を用いた以外は実施例1と同様にして、4−ニトロスチレンの水素化を行った。反応の結果、原料である4−ニトロスチレンの転化率は11%で、目的生成物である4−アミノスチレンの選択率は98%であり、副生成物である4−エチルアニリンの選択率は0%であった。
Comparative Example 3
Silver supported tungsten oxide powder catalyst (catalyst 6) having an average silver particle diameter of 2.6 nm
Hydrogenation of 4-nitrostyrene using
In Example 1, instead of the silver-supported alumina powder catalyst (catalyst 1) having an average silver particle diameter of 0.7 nm, 0.1 g of catalyst 6 having an average silver particle diameter of 2.6 nm (the silver content in the catalyst is 5 wt. %, The amount of silver used was 2 mol% based on the substrate), and 4-nitrostyrene was hydrogenated in the same manner as in Example 1. As a result of the reaction, the conversion rate of 4-nitrostyrene as a raw material was 11%, the selectivity of 4-aminostyrene as a target product was 98%, and the selectivity of 4-ethylaniline as a by-product was 0%.

比 較 例 4
銀平均粒子径2.4nmである銀担持酸化スズ粉末触媒(触媒7)を用いた
4−ニトロスチレンの水素化反応:
実施例1において、銀平均粒子径が0.7nmの銀担持アルミナ粉末触媒(触媒1)の代わりに、銀平均粒子径が2.4nmである触媒7 0.1g(触媒中の銀含有量5wt%、銀使用量は基質に対し2mol%)を用いた以外は実施例1と同様にして、4−ニトロスチレンの水素化を行った。反応の結果、原料である4−ニトロスチレンの転化率は3%で、目的生成物である4−アミノスチレンの選択率は79%であり、副生成物である4−エチルアニリンの選択率は0%であった。
Comparative Example 4
Hydrogenation reaction of 4-nitrostyrene using a silver-supported tin oxide powder catalyst (catalyst 7) having an average silver particle diameter of 2.4 nm:
In Example 1, in place of the silver supported alumina powder catalyst (catalyst 1) having a silver average particle diameter of 0.7 nm, 0.1 g of catalyst having a silver average particle diameter of 2.4 nm (silver content in the catalyst of 5 wt. %, The amount of silver used was 2 mol% based on the substrate), and 4-nitrostyrene was hydrogenated in the same manner as in Example 1. As a result of the reaction, the conversion of 4-nitrostyrene as a raw material was 3%, the selectivity of 4-aminostyrene as a target product was 79%, and the selectivity of 4-ethylaniline as a by-product was 0%.

比 較 例 5
銀平均粒子径1.6nmである銀担持ジルコニア粉末触媒(触媒8)を用いた
4−ニトロスチレンの水素化反応:
実施例1において、銀平均粒子径が0.7nmの銀担持アルミナ粉末触媒(触媒1)の代わりに、銀平均粒子径が1.6nmである触媒8 0.1g(触媒中の銀含有量5wt%、銀使用量は基質に対し2mol%)を用いた以外は実施例1と同様にして、4−ニトロスチレンの水素化を行った。反応の結果、原料である4−ニトロスチレンの転化率は61%で、目的生成物である4−アミノスチレンの選択率は73%であり、副生成物である4−エチルアニリンの選択率は3.0%であった。
Comparative Example 5
Hydrogenation of 4-nitrostyrene using a silver-supported zirconia powder catalyst (catalyst 8) having an average silver particle diameter of 1.6 nm:
In Example 1, in place of the silver-supported alumina powder catalyst (catalyst 1) having a silver average particle diameter of 0.7 nm, 0.1 g of catalyst having a silver average particle diameter of 1.6 nm (silver content in the catalyst of 5 wt. %, The amount of silver used was 2 mol% based on the substrate), and 4-nitrostyrene was hydrogenated in the same manner as in Example 1. As a result of the reaction, the conversion of 4-nitrostyrene as a raw material was 61%, the selectivity of 4-aminostyrene as a target product was 73%, and the selectivity of 4-ethylaniline as a by-product was It was 3.0%.

比 較 例 6
銀平均粒子径0.9nm銀担持セリア粉末触媒(触媒9)を用いた4−ニトロ
スチレンの水素化反応:
実施例1において、銀平均粒子径が0.7nmの銀担持アルミナ粉末触媒(触媒1)の代わりに、銀平均粒子径が0.9nmである触媒9 0.1g(触媒中の銀含有量5wt%、銀使用量は基質に対し2mol%)を用いた以外は実施例1と同様にして、4−ニトロスチレンの水素化を行った。反応の結果、原料である4−ニトロスチレンの転化率は59%で、目的生成物である4−アミノスチレンの選択率は74%であり、副生成物である4−エチルアニリンの選択率は0%であった。
Comparative Example 6
Hydrogenation reaction of 4-nitrostyrene using silver-supported ceria powder catalyst (catalyst 9) having an average silver particle size of 0.9 nm:
In Example 1, instead of the silver-supported alumina powder catalyst (catalyst 1) having an average silver particle diameter of 0.7 nm, 0.1 g of a catalyst having an average silver particle diameter of 0.9 nm (silver content of 5 wt% in the catalyst) %, The amount of silver used was 2 mol% based on the substrate), and 4-nitrostyrene was hydrogenated in the same manner as in Example 1. As a result of the reaction, the conversion rate of 4-nitrostyrene as a raw material was 59%, the selectivity of 4-aminostyrene as a target product was 74%, and the selectivity of 4-ethylaniline as a by-product was 0%.

比 較 例 7
銀平均粒子径3.0nmの銀担持酸化マグネシウム粉末触媒(触媒10)を用いた
4−ニトロスチレンの水素化反応:
実施例1において、銀平均粒子径が0.7nmの銀担持アルミナ粉末触媒(触媒1)の代わりに、銀平均粒子径が3.0nmである触媒10 0.1g(触媒中の銀含有量5wt%、銀使用量は基質に対し2mol%)を用いた以外は実施例1と同様にして、4−ニトロスチレンの水素化を行った。反応の結果、原料である4−ニトロスチレンの転化率は3%で、目的生成物である4−アミノスチレンの選択率は21%であり、副生成物である4−エチルアニリンの選択率は0%であった。
Comparative Example 7
Hydrogenation of 4-nitrostyrene using a silver supported magnesium oxide powder catalyst (catalyst 10) having an average silver particle diameter of 3.0 nm:
In Example 1, instead of the silver-supported alumina powder catalyst (catalyst 1) having an average silver particle size of 0.7 nm, 0.1 g of a catalyst having an average silver particle size of 3.0 nm (silver content of 5 wt% in the catalyst) %, The amount of silver used was 2 mol% based on the substrate), and 4-nitrostyrene was hydrogenated in the same manner as in Example 1. As a result of the reaction, the conversion of 4-nitrostyrene as a raw material was 3%, the selectivity of 4-aminostyrene as a target product was 21%, and the selectivity of 4-ethylaniline as a by-product was 0%.

比 較 例 8
銀平均粒子径2.4nmの銀担持シリカ粉末触媒(触媒11)を用いた4−
ニトロスチレンの水素化反応:
実施例1において、銀平均粒子径が0.7nmの銀担持アルミナ粉末触媒(触媒1)の代わりに、銀平均粒子径が2.4nmである触媒11 0.1g(触媒中の銀含有量5wt%、銀使用量は基質に対し2mol%)を用いた以外は実施例1と同様にして、4−ニトロスチレンの水素化を行った。反応の結果、原料である4−ニトロスチレンの転化率は100%で、目的生成物である4−アミノスチレンの選択率は97%であり、副生成物である4−エチルアニリンの選択率は2.0%であった。
Comparative Example 8
4- Using a silver supported silica powder catalyst (catalyst 11) having an average silver particle diameter of 2.4 nm
Nitrostyrene hydrogenation:
In Example 1, in place of the silver-supported alumina powder catalyst (catalyst 1) having an average silver particle diameter of 0.7 nm, 0.1 g of catalyst 11 having an average silver particle diameter of 2.4 nm (the silver content in the catalyst is 5 wt. %, The amount of silver used was 2 mol% based on the substrate), and 4-nitrostyrene was hydrogenated in the same manner as in Example 1. As a result of the reaction, the conversion rate of 4-nitrostyrene as a raw material was 100%, the selectivity of 4-aminostyrene as a target product was 97%, and the selectivity of 4-ethylaniline as a by-product was It was 2.0%.

以上、実施例1ないし3および比較例1ないし8の結果を表2にまとめて示す。

Figure 2011036748
The results of Examples 1 to 3 and Comparative Examples 1 to 8 are collectively shown in Table 2.
Figure 2011036748

比 較 例 9
銀パウダーを用いた4−ニトロスチレンの水素化反応:
実施例1において、銀平均粒子径が0.7nmの銀担持アルミナ粉末触媒(触媒1)の代わりに、銀パウダー(銀使用量は基質に対し40mol%)を用いた以外は実施例1と同様にして、4−ニトロスチレンの水素化を行った。反応の結果、原料である4−ニトロスチレンの転化率は1%であり、予想される水素化生成物である4−アミノスチレンおよび4−エチルアニリンはいずれも全く生成しなかった。
Comparative Example 9
Hydrogenation reaction of 4-nitrostyrene using silver powder:
Example 1 is the same as Example 1 except that silver powder (the amount of silver used is 40 mol% with respect to the substrate) is used instead of the silver-supported alumina powder catalyst (catalyst 1) having an average silver particle size of 0.7 nm. Then, 4-nitrostyrene was hydrogenated. As a result of the reaction, the conversion rate of 4-nitrostyrene as a raw material was 1%, and 4-aminostyrene and 4-ethylaniline as expected hydrogenation products were not produced at all.

比 較 例 10
白金担持アルミナ粉末触媒を用いた4−ニトロスチレンの水素化反応:
硝酸白金をθ−アルミナ粉末に含浸し、減圧下80℃にて12時間乾燥後、500℃にて2時間焼成し、さらに水素気流中300℃にて0.5時間処理して白金担持アルミナ粉末触媒を得た。白金粒子径は25℃にてCO含有ヘリウム中のCOパルス吸着法により求めた。
Comparative Example 10
Hydrogenation of 4-nitrostyrene using platinum supported alumina powder catalyst:
Platinum nitrate is impregnated with θ-alumina powder, dried at 80 ° C. under reduced pressure for 12 hours, calcined at 500 ° C. for 2 hours, and further treated at 300 ° C. for 0.5 hour in a hydrogen stream to obtain platinum-supported alumina powder. A catalyst was obtained. The platinum particle diameter was determined by a CO pulse adsorption method in CO-containing helium at 25 ° C.

このようにして得られた白金担持アルミナ粉末触媒(白金使用量は基質に対し0.04mol%、白金平均粒子径が0.7nm)を、実施例1において、銀担持アルミナ粉末触媒(銀平均粒子径:0.7nm)の代わりに用いた以外は同様にして、4−ニトロスチレンの水素化を行った。反応の結果、原料である4−ニトロスチレンの転化率は100%であった。目的とする水素化生成物である4−アミノスチレンはまったく生成せず、4−エチルアニリンのみが選択率100%で生成した。   The platinum-supported alumina powder catalyst (platinum used was 0.04 mol% with respect to the substrate and the platinum average particle diameter was 0.7 nm) obtained in this manner was used as the silver-supported alumina powder catalyst (silver average particle in Example 1). 4-Nitrostyrene was hydrogenated in the same manner except that it was used instead of (diameter: 0.7 nm). As a result of the reaction, the conversion rate of 4-nitrostyrene as a raw material was 100%. The target hydrogenation product 4-aminostyrene was not produced at all, and only 4-ethylaniline was produced with a selectivity of 100%.

以上の実施例および比較例から明らかなように、本発明の触媒は芳香族ニトロ化合物の水素化に対して優れた転化率と共に、高い選択率を有し、副生成物の生成率も少ないことがわかる。なお、本発明の触媒による芳香族ニトロ化合物の水素化にあたっての特性は、上記実施例に記載された4−ニトロスチレンに限られる物ではなく、他の置換基を持つ芳香族ニトロ化合物においても発揮される。以下その例を挙げる。   As is clear from the above Examples and Comparative Examples, the catalyst of the present invention has a high conversion rate with respect to the hydrogenation of aromatic nitro compounds, a high selectivity, and a low rate of by-product formation. I understand. The characteristics of the hydrogenation of the aromatic nitro compound by the catalyst of the present invention are not limited to 4-nitrostyrene described in the above examples, but are also exhibited in aromatic nitro compounds having other substituents. Is done. Examples are given below.

実 施 例 4
銀平均粒子径0.9nmの銀担持アルミナ粉末触媒(触媒2)を用いた4'−
ニトロアセトフェノンの水素化反応:
実施例2において、4−ニトロスチレンの代わりに、基質として4'−ニトロアセトフェノンを用いた以外は実施例2と同様にして、4'−ニトロアセトフェノンの水素化を行った。反応の結果、原料である4'−ニトロアセトフェノンの転化率は100%で、目的生成物である4'−アミノアセトフェノンの選択率は97%であった。副生成物である4−エチルアニリンは生成しなかった。
Example 4
4′− using silver supported alumina powder catalyst (catalyst 2) having an average silver particle diameter of 0.9 nm
Nitroacetophenone hydrogenation:
In Example 2, 4′-nitroacetophenone was hydrogenated in the same manner as in Example 2 except that 4′-nitroacetophenone was used as a substrate instead of 4-nitrostyrene. As a result of the reaction, the conversion rate of 4′-nitroacetophenone as a raw material was 100%, and the selectivity of 4′-aminoacetophenone as a target product was 97%. By-product 4-ethylaniline was not produced.

実 施 例 5
銀平均粒子径0.9nmの銀担持アルミナ粉末触媒(触媒2)を用いた4−ニトロ
ベンズアミドの水素化反応:
実施例2において、4−ニトロスチレンの代わりに、基質として4−ニトロベンズアミドを用い、反応時間を20時間に延長した以外は実施例2と同様にして、4−ニトロベンズアミドの水素化を行った。反応の結果、原料である4−ニトロベンズアミドの転化率は100%で、目的生成物である4−アミノベンズアミドの選択率は98%であった。副生成物である4−アミノベンジルアミンは生成しなかった。
Example 5
Hydrogenation of 4-nitrobenzamide using a silver supported alumina powder catalyst (catalyst 2) having an average silver particle diameter of 0.9 nm:
In Example 2, 4-nitrobenzamide was hydrogenated in the same manner as in Example 2 except that 4-nitrobenzamide was used as a substrate instead of 4-nitrostyrene and the reaction time was extended to 20 hours. . As a result of the reaction, the conversion of 4-nitrobenzamide as a raw material was 100%, and the selectivity for 4-aminobenzamide as a target product was 98%. By-product 4-aminobenzylamine was not produced.

実施例4および実施例5の結果をまとめて表3に示す。

Figure 2011036748
The results of Example 4 and Example 5 are shown together in Table 3.
Figure 2011036748

本発明の触媒は、連続する水素化反応により失活した場合にも、比較的簡単な方法で再生が可能である。以下その実施例を示す。   The catalyst of the present invention can be regenerated by a relatively simple method even when deactivated by successive hydrogenation reactions. Examples are shown below.

実 施 例 6 および 比 較 例 11
選択的水素化触媒の再生試験:
実施例2に記載の4−ニトロスチレンの水素化反応を繰返し行なった結果、添加率、収率共に活性を示さなくなった銀平均粒子径0.9nmの銀担持アルミナ粉末触媒(触媒2)を、生成物を含む溶液から濾過により分離した。これを、蒸留水とエタノール体積比1:1の混合溶媒を用いて洗浄し、100℃で乾燥し、500℃、600℃、700℃で焼成し、続いて還元剤として水素ガスを使用し、300℃で5分程度還元することで触媒の再生処理を行い、再度実施例2に記載の4−ニトロスチレンの水素化反応を行ない、4−ニトロスチレンの転化率と4−アミノスチレンの選択率を測定した(実施例6)。
Example 6 and Comparative Example 11
Regeneration test of selective hydrogenation catalyst:
As a result of repeating the hydrogenation reaction of 4-nitrostyrene described in Example 2, a silver-supported alumina powder catalyst (catalyst 2) having an average silver particle diameter of 0.9 nm, which showed no activity in both addition rate and yield, The solution containing the product was separated by filtration. This was washed with a mixed solvent of distilled water and ethanol volume ratio of 1: 1, dried at 100 ° C., calcined at 500 ° C., 600 ° C., 700 ° C., and subsequently using hydrogen gas as a reducing agent, The catalyst is regenerated by reducing at 300 ° C. for about 5 minutes, and the 4-nitrostyrene hydrogenation reaction described in Example 2 is performed again. The conversion of 4-nitrostyrene and the selectivity of 4-aminostyrene Was measured (Example 6).

同様、比較例8に記載の4−ニトロスチレンの水素化反応を繰返し行なった結果、添加率、収率共に活性を示さなくなった銀平均粒子径2.4nmの銀担持シリカ粉末触媒(触媒11)についても、上記と同様再生処理を行い、再度比較例8に記載の4−ニトロスチレンの水素化反応を行なって4−ニトロスチレンの転化率と4−アミノスチレンの選択率を測定した(比較例11)。   Similarly, as a result of repeating the hydrogenation reaction of 4-nitrostyrene described in Comparative Example 8, the silver-supported silica powder catalyst (catalyst 11) having an average silver particle diameter of 2.4 nm that showed no activity in both the addition rate and the yield. In the same manner as above, the regeneration treatment was performed, and the hydrogenation reaction of 4-nitrostyrene described in Comparative Example 8 was performed again to measure the conversion of 4-nitrostyrene and the selectivity of 4-aminostyrene (Comparative Example). 11).

これら実施例6および比較例11の結果を、表4にまとめて示す。

Figure 2011036748
The results of Example 6 and Comparative Example 11 are summarized in Table 4.
Figure 2011036748

表4からわかるように、本発明の触媒は再生後でも優れた性能を発揮していることがわかる。   As can be seen from Table 4, the catalyst of the present invention exhibits excellent performance even after regeneration.

これに対し比較例11の銀担持シリカ粉末触媒(触媒11)では、再生前のフレッシュな状態の性能は銀担持アルミナ粉末触媒に勝るものの、失活後は本発明の再生処理を施しても活性を取り戻すことが出来なかった。   On the other hand, the silver-supported silica powder catalyst (catalyst 11) of Comparative Example 11 has a fresh state performance before regeneration that is superior to that of the silver-supported alumina powder catalyst. Could not get back.

参 考 例 1
水素化反応を繰り返し行った結果、活性を失った触媒2および触媒11について、焼成温度を400℃とした以外は実施例6と同様にして再生処理をおこなった。この再生処理を行った触媒について、実施例6と同様に4−ニトロスチレンの水素化反応を行ない、4−ニトロスチレンの転化率と4−アミノスチレンの選択率を測定した。
Reference example 1
As a result of repeating the hydrogenation reaction, regeneration treatment was performed in the same manner as in Example 6 except that the catalyst 2 and the catalyst 11 that lost activity were set at a calcination temperature of 400 ° C. The catalyst subjected to the regeneration treatment was subjected to a hydrogenation reaction of 4-nitrostyrene in the same manner as in Example 6, and the conversion of 4-nitrostyrene and the selectivity of 4-aminostyrene were measured.

また、活性を失った触媒を混合溶媒で洗浄しただけのものについても、上記と同様、4−ニトロスチレンの水素化反応を行ない、4−ニトロスチレンの転化率と4−アミノスチレンの選択率を測定した。これらの結果を表5に示す。   Similarly, the catalyst having lost its activity was washed with a mixed solvent, and the hydrogenation reaction of 4-nitrostyrene was conducted in the same manner as described above, and the conversion of 4-nitrostyrene and the selectivity of 4-aminostyrene were determined. It was measured. These results are shown in Table 5.

Figure 2011036748
Figure 2011036748

本発明の選択的水素化触媒による優れた結果は、芳香族ニトロ化合物として上記実施例の4−ニトロスチレン、4'−ニトロアセトフェノンおよび4−ニトロベンズアミドを用いた場合の他、3−ビニルニトロベンゼン、1−クロロ−2−ニトロベンゼン、4’−ニトロアセトフェノン、4−ニトロベンゾニトリル、4−ニトロ安息香酸メチルを使用した場合でも同様に得ることができる。   The excellent results obtained by the selective hydrogenation catalyst of the present invention were obtained by using 3-vinylnitrobenzene, 4-nitrostyrene, 4′-nitroacetophenone and 4-nitrobenzamide of the above examples as aromatic nitro compounds. Even when 1-chloro-2-nitrobenzene, 4′-nitroacetophenone, 4-nitrobenzonitrile and methyl 4-nitrobenzoate are used, the same can be obtained.

本発明の選択的水素化触媒を用いる水素化方法によれば、芳香族ニトロ化合物中に存在する芳香環または複素環に結合したニトロ基のみを、高い転化性と選択性をもって水素化することができ、同一化合物中に存在する他の官能基、例えば、炭素−炭素二重結合、芳香環結合ハロゲン原子、芳香族ケトン性カルボニル基、芳香族カルボン酸エステル基、芳香族アミド性カルボニル基、芳香族ニトリル基等を水素化することはない。   According to the hydrogenation method using the selective hydrogenation catalyst of the present invention, only a nitro group bonded to an aromatic ring or a heterocycle present in an aromatic nitro compound can be hydrogenated with high conversion and selectivity. Other functional groups present in the same compound, such as carbon-carbon double bonds, aromatic ring-bonded halogen atoms, aromatic ketonic carbonyl groups, aromatic carboxylic acid ester groups, aromatic amido carbonyl groups, aromatic Group nitrile groups and the like are not hydrogenated.

しかも、本発明の触媒は、ある程度の使用によって触媒の活性が低下した場合も、複雑な工程を経ることなく、再生することが可能であり、経済性の高いものである。   Moreover, the catalyst of the present invention can be regenerated without going through a complicated process even when the activity of the catalyst is reduced by a certain amount of use, and is highly economical.

従って、本発明の水素化方法は、芳香族ニトロ化合物のニトロ基のみを選択的に水素化する方法として、工業的に極めて価値の高いものである。
Therefore, the hydrogenation method of the present invention is industrially extremely valuable as a method for selectively hydrogenating only the nitro group of an aromatic nitro compound.

Claims (18)

アルミナに、銀成分として銀および/または銀酸化物を担持せしめてなり、担持された銀成分の平均粒子径が0.5〜3nmであることを特徴とする芳香族ニトロ化合物の選択的水素化触媒。   Selective hydrogenation of an aromatic nitro compound characterized in that silver and / or silver oxide is supported on alumina as a silver component, and the average particle size of the supported silver component is 0.5 to 3 nm. catalyst. 芳香族ニトロ化合物の芳香環または複素環に結合したニトロ基を水素化することができ、当該芳香環または複素環に結合した炭素−炭素二重結合、ハロゲン原子、ケトン性カルボニル基、カルボン酸エステル基、アミド性カルボニル基およびニトリル基は実質的に水素化しないものである請求項1記載の選択的水素化触媒。   A nitro group bonded to an aromatic ring or a heterocyclic ring of an aromatic nitro compound can be hydrogenated, and a carbon-carbon double bond, a halogen atom, a ketonic carbonyl group, a carboxylic acid ester bonded to the aromatic ring or the heterocyclic ring 2. The selective hydrogenation catalyst according to claim 1, wherein the amide group, the amide group carbonyl group and the nitrile group are not substantially hydrogenated. アルミナのメジアン径が、0.5〜500μmである請求項1または2記載の選択的水素化触媒。   The selective hydrogenation catalyst according to claim 1 or 2, wherein the median diameter of alumina is 0.5 to 500 µm. アルミナの比表面積が、30〜3000m/gである請求項1ないし3の何れかの項記載の選択的水素化触媒。 The specific surface area of the alumina, 30~3000m 2 / g and a claims 1 to 3 of any one of claim wherein the selective hydrogenation catalyst. 銀成分の担持量が、アルミナ担体1g当たり銀元素に換算して1.0μmol〜5mmolである請求項1ないし4の何れかの項記載の選択的水素化触媒。   The selective hydrogenation catalyst according to any one of claims 1 to 4, wherein the supported amount of silver component is 1.0 µmol to 5 mmol in terms of silver element per gram of alumina support. アルミナに銀塩溶液を含浸させ、乾燥した後、酸化雰囲気での焼成および還元処理を行うことを特徴とする請求項1ないし5の何れかの項記載の選択的水素化触媒の製造方法。   The method for producing a selective hydrogenation catalyst according to any one of claims 1 to 5, wherein the alumina is impregnated with a silver salt solution and dried, followed by calcination and reduction treatment in an oxidizing atmosphere. 酸化雰囲気下での焼成が、500〜1000℃の温度で行われる請求項6記載の選択的水素化触媒の製造方法。   The method for producing a selective hydrogenation catalyst according to claim 6, wherein the calcination in an oxidizing atmosphere is performed at a temperature of 500 to 1000 ° C. 還元処理が、300〜900℃の温度で行われるものである請求項6または7記載の選択的水素化触媒の製造方法。   The method for producing a selective hydrogenation catalyst according to claim 6 or 7, wherein the reduction treatment is performed at a temperature of 300 to 900 ° C. 還元処理が、ガス状水素の存在下で行われる請求項6ないし8の何れかの項記載の選択的水素化触媒の製造方法。   The method for producing a selective hydrogenation catalyst according to any one of claims 6 to 8, wherein the reduction treatment is performed in the presence of gaseous hydrogen. 還元処理が、メタノール、ホルムアルデヒドまたは蟻酸ガスの存在下で行われる請求項6ないし8の何れかの項記載の選択的水素化触媒の製造方法。   The method for producing a selective hydrogenation catalyst according to any one of claims 6 to 8, wherein the reduction treatment is performed in the presence of methanol, formaldehyde or formic acid gas. 銀塩溶液が、硝酸銀、酢酸銀、過塩素酸銀、ビス(2,2'−ビピリジン)銀(I)硝酸塩、ビス(1,10−ファナントロリン)銀(I)過塩素酸塩またはテトラキス(トリフェニルホスフィン)銀(I)硝酸塩の溶液である請求項6ないし10の何れかの項記載の選択的水素化触媒の製造方法。   The silver salt solution is silver nitrate, silver acetate, silver perchlorate, bis (2,2′-bipyridine) silver (I) nitrate, bis (1,10-phananthroline) silver (I) perchlorate or tetrakis ( The method for producing a selective hydrogenation catalyst according to any one of claims 6 to 10, which is a solution of triphenylphosphine) silver (I) nitrate. 芳香族ニトロ化合物、有機溶剤、請求項1ないし5の何れかの項記載の選択的水素化触媒および水素ガスを加熱条件下混合することを特徴とする芳香族ニトロ化合物のニトロ基の選択的水素化方法。   A selective hydrogen of a nitro group of an aromatic nitro compound, wherein an aromatic nitro compound, an organic solvent, the selective hydrogenation catalyst according to any one of claims 1 to 5 and hydrogen gas are mixed under heating. Method. 水素ガスを、その分圧として0.005〜30Maで供給する請求項12記載の芳香族ニトロ化合物のニトロ基の選択的水素化方法。   The method for selectively hydrogenating a nitro group of an aromatic nitro compound according to claim 12, wherein hydrogen gas is supplied at a partial pressure of 0.005 to 30 Ma. 加熱温度が、120〜200℃の範囲である請求項12または13記載の芳香族ニトロ化合物のニトロ基の選択的水素化方法。   The method for selectively hydrogenating a nitro group of an aromatic nitro compound according to claim 12 or 13, wherein the heating temperature is in the range of 120 to 200 ° C. 選択的水素化触媒の量が、芳香族ニトロ化合物に対して、当該触媒に担持される銀成分を基準として金属銀換算で0.01〜20モル%の範囲である請求項12ないし14記載の何れかの項記載の芳香族ニトロ化合物のニトロ基の選択的水素化方法。   The amount of the selective hydrogenation catalyst is in the range of 0.01 to 20 mol% in terms of metallic silver based on the silver component supported on the aromatic nitro compound. A method for selectively hydrogenating a nitro group of an aromatic nitro compound according to any one of the items. 触媒的に失活した請求項1ないし5の何れかの項記載の選択的水素化触媒を、有機溶媒と水を含有する溶媒で洗浄し、次いで、酸化雰囲気で焼成し、更に還元処理することを特徴とする選択的水素化触媒の再生方法。   The selective hydrogenation catalyst according to any one of claims 1 to 5, which has been catalytically deactivated, is washed with a solvent containing an organic solvent and water, then calcined in an oxidizing atmosphere, and further subjected to a reduction treatment. A method for regenerating a selective hydrogenation catalyst. 酸化雰囲気下での焼成を、500℃〜1000℃の温度で行う請求項16記載の選択的水素化触媒の再生方法。   The method for regenerating a selective hydrogenation catalyst according to claim 16, wherein the calcination in an oxidizing atmosphere is performed at a temperature of 500C to 1000C. 還元処理を、水素雰囲気中、300〜900℃の温度で行う請求項16または17記載の選択的水素化触媒の再生方法。   The method for regenerating a selective hydrogenation catalyst according to claim 16 or 17, wherein the reduction treatment is performed in a hydrogen atmosphere at a temperature of 300 to 900 ° C.
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