JP4623247B2 - Method for producing a catalyst for synthesis of cyanide - Google Patents
Method for producing a catalyst for synthesis of cyanide Download PDFInfo
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- JP4623247B2 JP4623247B2 JP2000276310A JP2000276310A JP4623247B2 JP 4623247 B2 JP4623247 B2 JP 4623247B2 JP 2000276310 A JP2000276310 A JP 2000276310A JP 2000276310 A JP2000276310 A JP 2000276310A JP 4623247 B2 JP4623247 B2 JP 4623247B2
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- catalyst
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- formamide
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- 239000003054 catalyst Substances 0.000 title claims description 36
- 238000004519 manufacturing process Methods 0.000 title claims description 14
- XFXPMWWXUTWYJX-UHFFFAOYSA-N Cyanide Chemical compound N#[C-] XFXPMWWXUTWYJX-UHFFFAOYSA-N 0.000 title claims description 7
- 230000015572 biosynthetic process Effects 0.000 title description 2
- 238000003786 synthesis reaction Methods 0.000 title description 2
- LELOWRISYMNNSU-UHFFFAOYSA-N hydrogen cyanide Chemical compound N#C LELOWRISYMNNSU-UHFFFAOYSA-N 0.000 claims description 26
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 22
- 239000007789 gas Substances 0.000 claims description 18
- 230000001590 oxidative effect Effects 0.000 claims description 14
- 229910052742 iron Inorganic materials 0.000 claims description 11
- 230000002194 synthesizing effect Effects 0.000 claims description 10
- 239000001257 hydrogen Substances 0.000 claims description 9
- 229910052739 hydrogen Inorganic materials 0.000 claims description 9
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 7
- 229910001868 water Inorganic materials 0.000 claims description 7
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 5
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 5
- 239000001301 oxygen Substances 0.000 claims description 5
- 229910052760 oxygen Inorganic materials 0.000 claims description 5
- 150000002431 hydrogen Chemical class 0.000 claims description 4
- 229910052757 nitrogen Inorganic materials 0.000 claims description 4
- ZHNUHDYFZUAESO-UHFFFAOYSA-N Formamide Chemical compound NC=O ZHNUHDYFZUAESO-UHFFFAOYSA-N 0.000 description 38
- 238000006243 chemical reaction Methods 0.000 description 35
- 229910000831 Steel Inorganic materials 0.000 description 13
- 239000010959 steel Substances 0.000 description 13
- 238000000034 method Methods 0.000 description 11
- UQSXHKLRYXJYBZ-UHFFFAOYSA-N Iron oxide Chemical compound [Fe]=O UQSXHKLRYXJYBZ-UHFFFAOYSA-N 0.000 description 8
- 239000000126 substance Substances 0.000 description 6
- 230000003197 catalytic effect Effects 0.000 description 5
- 230000008929 regeneration Effects 0.000 description 5
- 238000011069 regeneration method Methods 0.000 description 5
- 238000005979 thermal decomposition reaction Methods 0.000 description 5
- 238000002360 preparation method Methods 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 239000003814 drug Substances 0.000 description 3
- 229940079593 drug Drugs 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical class OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 2
- 238000005273 aeration Methods 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- XLJMAIOERFSOGZ-UHFFFAOYSA-N cyanic acid Chemical compound OC#N XLJMAIOERFSOGZ-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- KMUONIBRACKNSN-UHFFFAOYSA-N potassium dichromate Chemical compound [K+].[K+].[O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O KMUONIBRACKNSN-UHFFFAOYSA-N 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- BDAGIHXWWSANSR-UHFFFAOYSA-N Formic acid Chemical class OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 1
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 1
- 229910000805 Pig iron Inorganic materials 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- KCZFLPPCFOHPNI-UHFFFAOYSA-N alumane;iron Chemical compound [AlH3].[Fe] KCZFLPPCFOHPNI-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000004299 exfoliation Methods 0.000 description 1
- 238000010574 gas phase reaction Methods 0.000 description 1
- PQQAOTNUALRVTE-UHFFFAOYSA-L iron(2+);diformate Chemical compound [Fe+2].[O-]C=O.[O-]C=O PQQAOTNUALRVTE-UHFFFAOYSA-L 0.000 description 1
- ZFSLODLOARCGLH-UHFFFAOYSA-N isocyanuric acid Chemical compound OC1=NC(O)=NC(O)=N1 ZFSLODLOARCGLH-UHFFFAOYSA-N 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000012286 potassium permanganate Substances 0.000 description 1
- 239000012256 powdered iron Substances 0.000 description 1
- 238000000197 pyrolysis Methods 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
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- Catalysts (AREA)
Description
【０００１】
本発明は、ホルムアミドを熱分解して青酸と水を生成する反応に関与する触媒の製造方法に関する。さらに詳しくはホルムアミドを熱分解して青酸を合成するために用いる触媒を製造するに際し、腐食性の調製液体薬剤等を用いることなく極めて容易な処理操作によって調製し、調製後の後処理をほとんど必要とせずに商業生産を可能にする触媒の製造方法に関する。
【０００２】
【従来の技術】
ホルムアミドを金属又はその酸化物から成る触媒によって選択的に熱分解し、青酸を合成する方法は古くから知られている。用いられる触媒についても多くの公知技術として知られているが、例えば特公昭３５−９１８２号によれば反応管を熔融アルミニウム浴に浸漬して表面に鉄−アルミニウム合金層を形成させてホルムアミドから青酸を合成している。また特公昭３３−６２２９号によれば飽和重クロム酸カリの濃硫酸溶液、過マンガン酸カリの濃硫酸溶液、過酸化水素水等で処理する触媒調製方法が開示されている。これらはの方法を工業的規模で実施するためには何れも処理のための特別の装置を準備する必要がある。
【０００３】
反応管に鋼管を用いる場合の酸化皮膜調製方法として、特公昭３５−９１８２号による反応管調製方法を多管式反応器からなる工業的装置に適用する事は多大な投資を必要とする。また特公昭３３−６２２９号と同様の方法で酸性薬剤を使用した場合、薬剤調合装置が別途必要となるのに加え、薬剤による反応装置に対する予期せぬ腐食トラブルを引き起こす可能性が有る。また薬剤処理時及び処理後の薬剤を回収するための煩雑な操作と管理とを必要とする。
【０００４】
またかくして薬剤処理して調製された触媒皮膜は付着強度が弱く、長期の連続使用に耐えないためそのほとんど全てが剥離して脱落するという欠点を有する。酸化皮膜の剥離によって触媒活性の低下をもたらすのみならず、剥離した金属酸化物で系内が汚染される弊害をも生ずる。本発明者らはこれらの課題を解決するため鋭意研究を進め本発明に至った。
【０００５】
【発明が解決しようとする課題】
本発明の目的は、簡単で安全な方法で、高活性で長期間安定なホルムアミドを熱分解して青酸を合成する触媒の製造方法を提供することである。
【０００６】
【課題点を解決するための手段】
本発明者らは薬剤処理以外の酸化皮膜形成方法として気相処理法に着目し種々検討した。その結果、反応管表面に薬剤処理を行わずに酸化皮膜を形成させる事は比較的に容易であった。しかし、触媒能と付着強度とを満足する皮膜を形成させる事は容易ではなかった。更なる研究の結果、特定の処理条件を満足させる方法で金属表面を処理する事によって触媒能と付着強度とを有する酸化皮膜を形成し得る事を見出した。詳しくは制御された酸化性ガスと還元性ガスとによって、所定の様式で交互に処理する事により、触媒能を有し且つ強固な付着強度をも有する酸化皮膜が形成する事を見出し本発明に至った。即ち、本発明は、鉄の表面を酸化性雰囲気及び還元性雰囲気に曝すことを特徴とする青酸合成用触媒の製造方法に関する。
【０００７】
【発明の実施の形態】
本発明の触媒の製造方法に用いる原料の鉄には、約２重量％以上の炭素を含む銑鉄、約２重量％より炭素量の少ない鋼、更にこれらの炭素鋼に炭素以外の合金元素を添加した特殊鋼がある。
【０００８】
本発明の触媒の製造方法に使用する鉄の形状は触媒の使用方法により異なる。カラムに触媒を充填して用いる場合には粒状あるいは粉末状が好適であり、これら粒状鉄あるいは粉末状鉄の表面に酸化皮膜を形成する。触媒を反応管として用いる場合は、鉄としては鋼を用いることが耐久性の点で好ましく、鋼管の内側表面に酸化皮膜を形成する。
【０００９】
鉄の表面を酸化性雰囲気及び還元性雰囲気に曝す場合の条件を以下に述べる。
酸化性雰囲気は鉄表面を５〜３０体積％の酸素を含有するガスで覆うことにより達成できる。簡単で好ましい方法は空気で覆うことである。酸化性雰囲気に曝す時の処理温度は３００〜６５０℃、処理圧力は６〜１５０ｋPa、空間速度（以下ＳＶと称す）は１０〜１５００ｈ-1であり、一回の処理時間を５〜３００分間とするのが好ましい。
【００１０】
還元性雰囲気は鉄表面を、１〜９９体積％の水素、好ましくは２〜２０体積％の水素を含むが酸素を含まないガスで覆うことにより達成できる。酸素は可能な限り含まないほうが良い。好ましい方法は、水素と水とからなるガスあるいは水素と窒素と水とからなるガスで覆うことである。還元性雰囲気に曝す時の処理温度は３００〜６５０℃、処理圧力は６〜１５０ｋPa、ＳＶは１０〜１５００ｈ-1であり、一回の処理時間を１０〜３００分間とするのが好ましい。酸化性雰囲気と還元性雰囲気とに曝す操作を交互に２回以上繰り返すことが好ましい。酸化性雰囲気と還元性雰囲気とに曝す操作を交互に繰り返す場合、どちらの雰囲気による処理が最初になされても良い。
【００１１】
本発明の触媒を用いてホルムアミドを熱分解して青酸を製造する場合、気相反応で連続的に行うのが好ましく、原料のホルムアミドはガスとして反応器に供給される。この場合の反応条件は、反応温度３００〜６００℃、反応圧力６〜１５０ｋPa、ＳＶ５０〜１５００ｈ-1が好ましく、触媒は６０〜３０００分間連続して使用される。
【００１２】
反応中に触媒活性の低下が見られた場合には触媒を再生する。再生は酸素５〜３０体積％含有するガス、好ましくは空気を用いて３００〜６００℃、６〜１５０ｋPa、ＳＶ１０〜１５００ｈ-1で１０〜５００分間処理することにより行われる。上記の反応と再生を繰り返すことによりホルムアミドより青酸が製造される。
【００１３】
【発明の効果】
本発明の方法によれば触媒調製のための付帯設備を最小限に抑え、廃薬剤や脱落酸化皮膜の処理を行う事無く青酸合成触媒を製造する事ができるのでその経済的効果は大きい。
【００１４】
【実施例】
以下に本発明を実施例によって説明する。
実施例１
内径１０．９ｍｍφ、長さ４４８ｍｍの鋼管を反応管材料として用いた。
温度４００℃、圧力１３．３ｋＰａの条件下に空気をＳＶ８０ｈ-1で鋼管の内側に供給する酸化性雰囲気処理を５０分間実施した後、同条件下に通気ガスを水素：窒素：水のモル比が６：１７：７７であるガスに切り替えてＳＶ３５０ｈ-1で供給する還元性雰囲気処理を１８０分間実施した。このように酸化性雰囲気処理と還元性雰囲気処理とを交互に１０回繰り返し、鋼管の内側に酸化皮膜をつくることにより青酸合成用触媒を製造した。
ここで製造された触媒を用いて、ホルムアミドの熱分解による青酸の製造を行った。触媒である反応管の内部にホルムアミドガスをＳＶ３５０ｈ-1で供給した。この時の反応温度は４００℃、反応圧力は１３．３ｋＰａであり、反応開始６０分後におけるホルムアミド転化率は９９．６モル％、青酸収率は９４．６モル％であった。
【００１５】
実施例２
内径１０．９ｍｍφ、長さ４４８ｍｍの鋼管を反応管材料として用いた。
温度４００℃、圧力１３．３ｋＰａの条件下に空気をＳＶ２６０ｈ-1で鋼管の内側に供給する酸化性雰囲気処理を５分間実施した後、同条件下に通気ガスを水素：窒素：水のモル比が６：１７：７７であるガスに切り替えてＳＶ４８０ｈ-1で供給する還元性雰囲気処理を４５分間実施した。このように酸化性雰囲気処理と還元性雰囲気処理とを交互に４０回繰り返し、鋼管の内側に酸化皮膜をつくることにより青酸合成用触媒を製造した。
ここで製造された触媒を用いて、ホルムアミドの熱分解による青酸の製造を実施例１と同様に行った。反応開始６０分後におけるホルムアミド転化率は９９．２モル％、青酸収率は９４．２モル％であった。
【００１６】
比較例１
酸化処理および還元処理を施さなかった内径１０．９ｍｍφ、長さ４４８ｍｍの鋼管を反応管として使用したほかは実施例１と同様にホルムアミドの熱分解反応を行った。反応開始６０分後におけるホルムアミド転化率は３６．５モル％、青酸収率は３４．７モル％であった。
【００１７】
実施例３
実施例１に引き続いて触媒の付着強度を確認するため、ホルムアミド熱分解反応と触媒表面への炭素質の付着からもたらされる触媒能の低下を回復させるため行われる空気による再生処理操作を交互に実施しつつ７日間の連続操作を行った。この間の操作における触媒の脱落量を計測するために反応管を開放した。反応器出口における脱落した酸化鉄の堆積はなかった。なおホルムアミド熱分解反応は、反応管内部にホルムアミドガスをＳＶ７００ｈ-1で供給しながら、反応温度４００℃、反応圧力１３．３ｋＰａで７時間行い、触媒の再生処理は空気を反応管内部にＳＶ３００ｈ-1で供給しながら、処理温度４００℃、処理圧力１３．３ｋＰａで１時間行なった。
【００１８】
比較例２
実施例１で使用したものと同じ鋼管を用いて酸性薬剤による酸化皮膜を形成させた。薬剤は蟻酸鉄の飽和蟻酸溶液を用いて室温下に４８時間浸漬した後に空気流通下４００℃で１時間焼成した。反応管には０．５ｍｍ厚さの酸化鉄皮膜が形成された。次いでこの反応管を用いて実施例３と同様にホルムアミドの熱分解反応と再生操作を繰り返す７日間の連続操作を行った。反応管出口を開放点検した結果１．３グラムの酸化鉄からなる堆積物が採取された。この堆積量は反応を始める前に形成された反応管表面の酸化鉄皮膜の量に等しいものであって、形成された皮膜のほぼ全てが脱落したものとみなされる。[0001]
The present invention relates to a method for producing a catalyst involved in a reaction in which formamide is pyrolyzed to produce hydrocyanic acid and water. More specifically, when producing a catalyst used to synthesize cyanic acid by pyrolyzing formamide, it is prepared by a very easy processing operation without using a corrosive liquid preparation, etc. The present invention relates to a method for producing a catalyst that enables commercial production without any problem.
[0002]
[Prior art]
A method for synthesizing hydrocyanic acid by selectively thermally decomposing formamide with a catalyst comprising a metal or its oxide has been known for a long time. The catalyst used is also known as a number of known techniques. For example, according to Japanese Examined Patent Publication No. 35-9182, a reaction tube is immersed in a molten aluminum bath to form an iron-aluminum alloy layer on the surface, and formamide is converted to cyanuric acid. Is synthesized. Japanese Examined Patent Publication No. 33-6229 discloses a catalyst preparation method in which a saturated sulfuric acid solution of potassium dichromate, a concentrated sulfuric acid solution of potassium permanganate, a hydrogen peroxide solution or the like is used. In order to carry out these methods on an industrial scale, it is necessary to prepare special equipment for processing.
[0003]
As a method for preparing an oxide film when using a steel pipe as a reaction tube, applying the reaction tube preparation method described in Japanese Patent Publication No. 35-9182 to an industrial apparatus comprising a multi-tube reactor requires a great investment. In addition, when an acidic drug is used in the same manner as in Japanese Examined Patent Publication No. 33-6229, a chemical compounding device is additionally required, and there is a possibility of causing an unexpected corrosion trouble with the chemical reaction device. In addition, complicated operation and management for collecting the drug during and after the drug processing are required.
[0004]
Further, the catalyst film prepared by the chemical treatment has a weak adhesion strength and cannot withstand long-term continuous use, so that almost all of the catalyst film peels off and falls off. Exfoliation of the oxide film not only causes a decrease in catalytic activity, but also causes a problem that the system is contaminated with the exfoliated metal oxide. In order to solve these problems, the present inventors have conducted intensive research and have arrived at the present invention.
[0005]
[Problems to be solved by the invention]
An object of the present invention is to provide a method for producing a catalyst for synthesizing hydrocyanic acid by thermally decomposing formamide which is highly active and stable for a long period of time in a simple and safe manner.
[0006]
[Means for Solving the Problems]
The present inventors have made various studies focusing on the gas phase treatment method as an oxide film forming method other than the chemical treatment. As a result, it was relatively easy to form an oxide film on the reaction tube surface without performing chemical treatment. However, it is not easy to form a film satisfying the catalytic ability and the adhesion strength. As a result of further research, it was found that an oxide film having catalytic ability and adhesion strength can be formed by treating a metal surface by a method satisfying specific treatment conditions. Specifically, the present invention finds that an oxide film having catalytic ability and strong adhesion strength is formed by alternately processing in a predetermined manner with a controlled oxidizing gas and reducing gas. It came. That is, the present invention relates to a method for producing a catalyst for synthesizing hydrocyanic acid characterized by exposing the surface of iron to an oxidizing atmosphere and a reducing atmosphere.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The raw iron used in the catalyst production method of the present invention includes pig iron containing about 2% by weight or more of carbon, steel having a carbon content less than about 2% by weight, and alloy elements other than carbon added to these carbon steels. Special steel.
[0008]
The shape of iron used in the method for producing the catalyst of the present invention varies depending on the method of using the catalyst. When the column is packed with a catalyst, it is preferably granular or powdery, and an oxide film is formed on the surface of the granular iron or powdered iron. When using a catalyst as a reaction tube, it is preferable to use steel as iron from the viewpoint of durability, and an oxide film is formed on the inner surface of the steel tube.
[0009]
The conditions for exposing the iron surface to an oxidizing atmosphere and a reducing atmosphere are described below.
The oxidizing atmosphere can be achieved by covering the iron surface with a gas containing 5 to 30% by volume of oxygen. A simple and preferred method is to cover with air. The treatment temperature when exposed to an oxidizing atmosphere is 300 to 650 ° C., the treatment pressure is 6 to 150 kPa, the space velocity (hereinafter referred to as SV) is 10 to 1500 h −1 , and one treatment time is 5 to 300 minutes. It is preferable to do this.
[0010]
A reducing atmosphere can be achieved by covering the iron surface with a gas containing 1 to 99 volume% hydrogen, preferably 2 to 20 volume% hydrogen but not oxygen. It is better not to contain oxygen as much as possible. A preferred method is covering with a gas composed of hydrogen and water or a gas composed of hydrogen, nitrogen and water. The treatment temperature when exposed to a reducing atmosphere is 300 to 650 ° C., the treatment pressure is 6 to 150 kPa, the SV is 10 to 1500 h −1 , and the treatment time for one time is preferably 10 to 300 minutes. The operation of exposing to an oxidizing atmosphere and a reducing atmosphere is preferably repeated twice or more alternately. When the operation of exposing to an oxidizing atmosphere and a reducing atmosphere is repeated alternately, the treatment with either atmosphere may be performed first.
[0011]
In the case of producing hydrocyanic acid by thermally decomposing formamide using the catalyst of the present invention, it is preferably carried out continuously by a gas phase reaction, and the raw formamide is supplied to the reactor as a gas. The reaction conditions in this case are preferably a reaction temperature of 300 to 600 ° C., a reaction pressure of 6 to 150 kPa, and SV of 50 to 1500 h −1 , and the catalyst is used continuously for 60 to 3000 minutes.
[0012]
If a decrease in catalyst activity is observed during the reaction, the catalyst is regenerated. The regeneration is carried out by treatment with a gas containing 5 to 30% by volume of oxygen, preferably air, at 300 to 600 ° C., 6 to 150 kPa, and SV 10 to 1500 h −1 for 10 to 500 minutes. By repeating the above reaction and regeneration, hydrocyanic acid is produced from formamide.
[0013]
【The invention's effect】
According to the method of the present invention, an auxiliary facility for catalyst preparation is minimized, and a cyanide synthesis catalyst can be produced without treating waste chemicals or falling oxide films.
[0014]
【Example】
Hereinafter, the present invention will be described by way of examples.
Example 1
A steel pipe having an inner diameter of 10.9 mmφ and a length of 448 mm was used as a reaction tube material.
After carrying out an oxidizing atmosphere treatment for supplying air to the inside of the steel pipe at SV80h −1 under conditions of a temperature of 400 ° C. and a pressure of 13.3 kPa for 50 minutes, the aeration gas was hydrogen: nitrogen: water molar ratio Was reduced to 6:17:77, and a reducing atmosphere treatment supplied at SV350h −1 was performed for 180 minutes. Thus, the oxidizing atmosphere treatment and the reducing atmosphere treatment were alternately repeated 10 times to produce an oxide film on the inner side of the steel pipe to produce a catalyst for synthesizing hydrocyanic acid.
Using the catalyst produced here, cyanide was produced by thermal decomposition of formamide. Formamide gas was supplied to the inside of the reaction tube as a catalyst at SV350h- 1 . At this time, the reaction temperature was 400 ° C., the reaction pressure was 13.3 kPa, the formamide conversion was 60,6 mol%, and the hydrocyanic acid yield was 94.6 mol% 60 minutes after the start of the reaction.
[0015]
Example 2
A steel pipe having an inner diameter of 10.9 mmφ and a length of 448 mm was used as a reaction tube material.
After conducting an oxidizing atmosphere treatment in which air is supplied to the inside of the steel pipe at SV260h −1 at a temperature of 400 ° C. and a pressure of 13.3 kPa for 5 minutes, the aeration gas is hydrogen: nitrogen: water molar ratio under the same conditions. Was switched to a gas having a ratio of 6:17:77, and a reducing atmosphere treatment supplied by SV480h −1 was performed for 45 minutes. Thus, the oxidizing atmosphere treatment and the reducing atmosphere treatment were alternately repeated 40 times to produce an oxide film on the inner side of the steel pipe, thereby producing a catalyst for synthesizing hydrocyanic acid.
Using the catalyst produced here, production of hydrocyanic acid by thermal decomposition of formamide was carried out in the same manner as in Example 1. The conversion of formamide 60 minutes after the start of the reaction was 99.2 mol%, and the yield of hydrocyanic acid was 94.2 mol%.
[0016]
Comparative Example 1
A thermal decomposition reaction of formamide was carried out in the same manner as in Example 1 except that a steel tube having an inner diameter of 10.9 mmφ and a length of 448 mm that was not subjected to oxidation treatment and reduction treatment was used as a reaction tube. The conversion of formamide 60 minutes after the start of the reaction was 36.5 mol%, and the yield of hydrocyanic acid was 34.7 mol%.
[0017]
Example 3
In order to confirm the adhesion strength of the catalyst following Example 1, the regeneration treatment operation by air performed alternately to recover the decrease in catalytic ability caused by the formamide thermal decomposition reaction and the adhesion of carbonaceous matter to the catalyst surface was performed alternately. However, continuous operation was performed for 7 days. The reaction tube was opened in order to measure the amount of catalyst falling off during this operation. There was no deposit of iron oxide dropped at the reactor outlet. Note formamide pyrolysis reaction, while the reaction tubes inside the formamide gas was supplied at SV700h -1, reaction temperature 400 ° C., carried out for 7 hours at reaction pressure 13.3 kPa, regeneration treatment of the catalyst is SV300h air into the reaction tube - 1 was performed at a processing temperature of 400 ° C. and a processing pressure of 13.3 kPa for 1 hour.
[0018]
Comparative Example 2
The same steel pipe as used in Example 1 was used to form an oxide film with an acidic agent. The chemicals were immersed in a saturated formic acid solution of iron formate for 48 hours at room temperature and then calcined at 400 ° C. for 1 hour under air flow. An iron oxide film having a thickness of 0.5 mm was formed on the reaction tube. Next, using this reaction tube, a continuous operation for 7 days was repeated in the same manner as in Example 3 to repeat the thermal decomposition reaction of formamide and the regeneration operation. As a result of opening the reaction tube outlet, a deposit composed of 1.3 grams of iron oxide was collected. This deposited amount is equal to the amount of the iron oxide film formed on the surface of the reaction tube before the reaction starts, and it is considered that almost all of the formed film has fallen off.
Claims (5)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000276310A JP4623247B2 (en) | 1999-09-27 | 2000-09-12 | Method for producing a catalyst for synthesis of cyanide |
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| Application Number | Priority Date | Filing Date | Title |
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| JP27224799 | 1999-09-27 | ||
| JP11-272247 | 1999-09-27 | ||
| JP2000276310A JP4623247B2 (en) | 1999-09-27 | 2000-09-12 | Method for producing a catalyst for synthesis of cyanide |
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| Publication Number | Publication Date |
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| JP2001162167A JP2001162167A (en) | 2001-06-19 |
| JP4623247B2 true JP4623247B2 (en) | 2011-02-02 |
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| JP2000276310A Expired - Fee Related JP4623247B2 (en) | 1999-09-27 | 2000-09-12 | Method for producing a catalyst for synthesis of cyanide |
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60179142A (en) * | 1984-01-27 | 1985-09-13 | バスフ アクチェン ゲゼルシャフト | Molded iron catalyst material and its production |
| JPH0326339A (en) * | 1989-06-16 | 1991-02-04 | Bayer Ag | Production of iron catalyst and production of primary amine through hydrogenation of nitrile by using that catalyst |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4423023A (en) * | 1982-07-26 | 1983-12-27 | The Standard Oil Company | Process for the production of hydrocyanic acid from carbon monoxide and ammonia |
| US4514520A (en) * | 1982-11-18 | 1985-04-30 | N.V. Bekaert S.A. | Catalyst and method of its preparation |
| JPS63104652A (en) * | 1986-10-22 | 1988-05-10 | Mitsubishi Heavy Ind Ltd | Method for activating metal-wire catalyst |
-
2000
- 2000-09-12 JP JP2000276310A patent/JP4623247B2/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60179142A (en) * | 1984-01-27 | 1985-09-13 | バスフ アクチェン ゲゼルシャフト | Molded iron catalyst material and its production |
| JPH0326339A (en) * | 1989-06-16 | 1991-02-04 | Bayer Ag | Production of iron catalyst and production of primary amine through hydrogenation of nitrile by using that catalyst |
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| JP2001162167A (en) | 2001-06-19 |
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