EP0000519A1 - Process for the preparation of 2,2'-dichlorohydrazobenzene - Google Patents
Process for the preparation of 2,2'-dichlorohydrazobenzene Download PDFInfo
- Publication number
- EP0000519A1 EP0000519A1 EP78100394A EP78100394A EP0000519A1 EP 0000519 A1 EP0000519 A1 EP 0000519A1 EP 78100394 A EP78100394 A EP 78100394A EP 78100394 A EP78100394 A EP 78100394A EP 0000519 A1 EP0000519 A1 EP 0000519A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- nitrochlorobenzene
- dichlorohydrazobenzene
- noble metal
- anthraquinone derivative
- hydroxyanthraquinone
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C241/00—Preparation of compounds containing chains of nitrogen atoms singly-bound to each other, e.g. hydrazines, triazanes
- C07C241/02—Preparation of hydrazines
Definitions
- the invention relates to a process for the preparation of 2,2'-dichlorohydrazobenzene by catalytic reduction of o-nitrochlorobenzene with hydrogen.
- the temperature is between 40-100 ° C, preferably 60-70 ° C
- the hydrogen (excess) pressure is about 0.4-7.8 bar (20-125 psi, abs.), Preferably about 0.75 up to 1.8 bar (25 - 40 psi, abs.).
- naphthalene derivatives such as naphthoquinone- (1,4) or 2,3-dichloro-naphthoquinone- (1,4) are added to the reaction mixture.
- the yields of 2,2'-dichlorohydrazobenzene obtained in this way vary between 80 and 90%, and the chlorine elimination is said to be low.
- anthraquinone preferably hydroxyanthraquinones
- co-catalysts e.g. ⁇ -hydroxyanthraquinone or 2,6-dihydroxyanthraquinone can be added.
- the noble metal catalysts can be recycled very often when the anthraquinone derivatives are used, without suffering a drop in activity. Even after e.g. Ten times the precious metal catalysts are used, constant yields are obtained in the same reduction time as in the starting batch.
- the anthraquinone derivatives accelerate the reduction of the individual reaction stages, in particular the azoxy and azo stage, much more strongly than naphthoquinone compounds, so that a lower temperature throughout the Reaction time is enabled and even shorter reaction times can be achieved than when using the known naphthoquinones.
- Another advantage is that e.g. the ß-hydroxyanthraquinone after the reduction from the aqueous mother liquor by setting a pH of 3 to 4 can be precipitated practically quantitatively and can be used several times without purification, while the 2-hydroxy-3-chloronaphthoquinone- (1,4) (formed during the reduction from 2,3-dichloronaphthoquinone (1,4)) has to be eliminated by a complex wastewater treatment.
- the amount of ahthraquinones used is low, it is lower than that of the naphthoquinone derivatives.
- a weight ratio of ß-hydroxyanthraquinone to o-chloronitrobenzene of 0.003 to 0.008, in particular 0.004: 1 is sufficient to evenly reduce the dichlorazoxybenzene which occurs as an intermediate via the dichlorazobenzene to the hydrazo compound, while of 2,3-dichloronaphthoquinone- (1,4) twice the amount is necessary in order to achieve comparable results at least when the noble metal catalysts are used for the first time.
- the precious metal catalyst is more reliable Reproducibility of the yields and product properties even after repeated use - need only be used in a weight ratio of nitro compound to platinum or palladium between about 4000: 1 and 1500: 1, preferably 2500: 1.
- a 16 to 25% sodium hydroxide solution is used as the reaction medium in such an amount that after the end of the reaction a 10 to 15% sodium hydroxide solution is formed by the water of reaction formed.
- anthraquinones show advantages over the naphthoquinones. While the best results are achieved with naphthoquinone with a 16% sodium hydroxide solution in a weight ratio of o-nitrochlorobenzene to NaOH (100%) such as 1: 0.095, the anthraquinones allow an increase in the NaOH concentration to 25% and a lower use of sodium hydroxide solution in a weight ratio of o-nitrochlorobenzene to NaOH (100%) such as 1: 0.071, without slowing down the reaction rate.
- the use of an approx. 25% NaOH means an improvement in the space yield of approx. 20% compared to a 16% NaOH according to the above weight ratios.
- the reaction temperature is preferably between 55 to 60 ° C., the hydrogen pressure preferably between 1 to 6 bar, it being advantageous to let the pressure rise slowly within the specified limit values during the reduction.
- the reduction of o-nitrochlorobenzene to 2,2'-dichlorohydrazobenzene is carried out using a water-immiscible solvent, such as e.g. Benzene, toluene, xylene, ethylbenzene or their technical mixtures, for example the mixture of m-xylene and ethylbenzene, which is commercially available under the name "Solventnaphtha".
- a water-immiscible solvent such as e.g. Benzene, toluene, xylene, ethylbenzene or their technical mixtures, for example the mixture of m-xylene and ethylbenzene, which is commercially available under the name "Solventnaphtha".
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
Abstract
Die Herstellung von 2,2'-Dichlorhydrazobenzol durch katalytische Hydrierung von o-Nitrochlorbenzol in wäßriger Alkalilauge unter Zusatz eines aromatischen nichtwassermichbaren Lösemittels bei erhöhter Temperatur und erhöhtem Druck in Gegenwart eines Edelmetall-Katalysators und unter Zusatz eines polycyclischen Chinons als Co-Katalysator führt zu hohen und gut reproduzierbaren Ausbeuten, wenn der Co-Katalysator ein Anthrachinon-Derivat, insbesondere ein Hydroxyanthrachinon ist.The preparation of 2,2'-dichlorohydrazobenzene by catalytic hydrogenation of o-nitrochlorobenzene in aqueous alkali metal solution with the addition of an aromatic, non-water-miscible solvent at elevated temperature and pressure in the presence of a noble metal catalyst and with the addition of a polycyclic quinone as cocatalyst leads to high levels and reproducible yields when the cocatalyst is an anthraquinone derivative, in particular a hydroxyanthraquinone.
Description
Die Erfindung betrifft ein Verfahren zur Herstellung von 2,2'-Dichlorhydrazobenzol durch katalytische Reduktion von o-Nitrochlorbenzol mit Wasserstoff.The invention relates to a process for the preparation of 2,2'-dichlorohydrazobenzene by catalytic reduction of o-nitrochlorobenzene with hydrogen.
Aus der US-PS 3.156.724 ist bekannt, 2,2'-Dichlorhydrazobenzol durch katalytische Hydrierung von o-Nitrochlorbenzol herzustellen. Der Hydrierkontakt besteht aus Palladium oder Platin. Als Reaktionsmedium dient eine 2 bis 20 %ige wäßrige Lösung von Natrium- oder Kaliumhydroxid, insbesondere 13 bis 14 %ige Natronlauge, gegebenenfalls unter Zusatz eines organischen Lösemittels, vorzugsweise eines nicht wassermischbaren aromatischen Kohlenwasserstoffs wie Benzol, Toluol oder Xylol. Die Temperatur liegt zwischen 40 - 100°C, vorzugsweise bei 60 bis 70°C, der Wasserstoff-(über)druck bei etwa 0,4 bis 7,8 bar (20 - 125 psi,abs.), vorzugsweise etwa 0,75 bis 1,8 bar (25 - 40 psi,abs.). Für die Bildung von 2,2'-Dichlorhydrazobenzol werden dem Reaktionsgemisch Zusätze von Naphthalinderivaten, wie Naphthochinon-(1,4) oder 2,3-Dichlor-naphthochinon-(1,4) zugegeben. Die so erhaltenen Ausbeuten an 2,2'-Dichlorhydrazobenzol variieren zwischen 80 und 90 %, die Chlorabspaltung soll gering sein.From US-PS 3,156,724 it is known to produce 2,2'-dichlorohydrazobenzene by catalytic hydrogenation of o-nitrochlorobenzene. The hydrogenation contact consists of palladium or platinum. A 2 to 20% aqueous solution of sodium or potassium hydroxide, in particular 13 to 14% sodium hydroxide solution, optionally with the addition of an organic solvent, preferably a non-water-miscible aromatic hydrocarbon such as benzene, toluene or xylene, serves as the reaction medium. The temperature is between 40-100 ° C, preferably 60-70 ° C, the hydrogen (excess) pressure is about 0.4-7.8 bar (20-125 psi, abs.), Preferably about 0.75 up to 1.8 bar (25 - 40 psi, abs.). For the formation of 2,2'-dichlorohydrazobenzene, additions of naphthalene derivatives such as naphthoquinone- (1,4) or 2,3-dichloro-naphthoquinone- (1,4) are added to the reaction mixture. The yields of 2,2'-dichlorohydrazobenzene obtained in this way vary between 80 and 90%, and the chlorine elimination is said to be low.
Wie eine Nacharbeitung ergab, fallen bei einem erneuten Einsatz der Edelmetallkatalysatoren von Ansatz zu Ansatz nicht nur die Ausbeuten ab, sondern gleichzeitig steigen die Reaktionszeiten bei sinkender Aktivität der Edelmetallkatalysatoren. Beides ist für eine wirtschaftliche Durchführung der Reduktion unerwünscht. Die Chlorabspaltung liegt mit 7 bis 8 % schon beim ersten Einsatz recht hoch.As a rework showed, when the precious metal catalysts are used again, not only do the yields drop from batch to batch, but at the same time the reaction times increase as the activity of the noble metal catalysts decreases. Both are undesirable for an economical implementation of the reduction. At 7 to 8%, the elimination of chlorine is quite high the first time it is used.
Es wurde nun überraschend gefunden, daß die katalytische Reduktion von o-Nitrochlorbenzol zu 2,2'-Dichlorhydrazobenzol mit Wasserstoff in wäßriger Natron- oder Kalilauge, insbesondere einer 10 bis 25 gewichtsprozentigen Natronlauge, und in Gegenwart eines nicht wassermischbaren aromatischen Lösemittels, insbesondere eines Kohlenwasserstoffs wie Benzol, Toluol oder Xylol, mit Edelmetallkatalysatoren, vorzugsweise Palladium-, Platin- oder modifizierten, beispielsweise sulfidierten (gemäß DE-PS 1.959.578), insbesondere sulfitierten Platin-auf-Kohlenstoff-Katalysatoren (gemäß DE-PS 2.105.780) bei einem Wasserstoff(über)-druck von 1 bis etwa 10, vorzugsweise bis 6 bar und einer Reduktionstemperatur von etwa 50 bis 80, insbesondere 60°C zu hohen und gut reproduzierbaren Ausbeuten führt, wenn als Co-Katalysatoren Derivate des Anthrachinons, vorzugsweise Hydroxyanthrachinone, z.B. β-Hydroxyanthrachinon oder 2,6-Dihydroxyanthrachinon, zugesetzt werden.It has now surprisingly been found that the catalytic reduction of o-nitrochlorobenzene to 2,2'-dichlorohydrazobenzene with hydrogen in aqueous sodium hydroxide solution or potassium hydroxide solution, in particular a 10 to 25% strength by weight sodium hydroxide solution, and in the presence of a water-immiscible aromatic solvent, in particular a hydrocarbon such as benzene, toluene or xylene, with noble metal catalysts, preferably palladium, platinum or modified, for example sulfided (according to DE-PS 1.959.578), in particular sulfited platinum-on-carbon catalysts (according to DE-PS 2.105.780) a hydrogen (excess) pressure of 1 to about 10, preferably up to 6 bar and a reduction temperature of about 50 to 80, in particular 60 ° C. leads to high and easily reproducible yields if derivatives of anthraquinone, preferably hydroxyanthraquinones, are used as co-catalysts, e.g. β-hydroxyanthraquinone or 2,6-dihydroxyanthraquinone can be added.
Von besonderem Vorteil ist, daß die Edelmetallkatalysatoren bei Verwendung der Anthrachinonderivate sehr oft zurückgeführt werden können, ohne daß sie einen Aktivitätsabfall erleiden. Selbst nach z.B. zehnmaligem Einsatz der Edelmetallkatalysatoren werden konstante Ausbeuten in der gleichen Reduktionszeit wie beim Startansatz erhalten.It is particularly advantageous that the noble metal catalysts can be recycled very often when the anthraquinone derivatives are used, without suffering a drop in activity. Even after e.g. Ten times the precious metal catalysts are used, constant yields are obtained in the same reduction time as in the starting batch.
Die Anthrachinonderivate beschleunigen die Reduktion der einzelnen Reaktionsstufen, insbesondere der Azoxy- und Azostufe, wesentlich stärker als Naphthochinonverbindungen, so daß eine niedrigere Temperatur während der gesamten Reaktionszeit ermöglicht wird und dabei noch kürzere Reaktionszeiten als bei Einsatz der bekannten Naphthochinone erzielt werden.The anthraquinone derivatives accelerate the reduction of the individual reaction stages, in particular the azoxy and azo stage, much more strongly than naphthoquinone compounds, so that a lower temperature throughout the Reaction time is enabled and even shorter reaction times can be achieved than when using the known naphthoquinones.
Zusätzlich erfolgt eine wesentlich geringere Chlorabspaltung: sie beträgt bei Verwendung von Palladium 4 %, bei unmodifiziertem Platin weniger als 2 % und bei sulfitiertem Platin (hergestellt nach DE-PS 2.105.780) unter 1 %. Überraschend war, daß der sulfitierte Platinkatalysator, der bisher nur zur katalytischen Reduktion von halogenhaltigen Nitroaromaten zu den entpsrechenden Aminen in neutralem oder schwach saurem Medium geeignet erschien, auch zur Reduktion von o-Nitrochlorbenzol zu 2,2'-Dichlorhydrazobenzol in stark alkalischer Lösung eingesetzt werden kann.In addition, there is a significantly lower release of chlorine: it is 4% when using palladium, less than 2% with unmodified platinum and less than 1% with sulfited platinum (produced according to DE-PS 2.105.780). It was surprising that the sulfited platinum catalyst, which until now only seemed suitable for the catalytic reduction of halogen-containing nitroaromatics to the corresponding amines in neutral or weakly acidic medium, is also used for the reduction of o-nitrochlorobenzene to 2,2'-dichlorohydrazobenzene in a strongly alkaline solution can.
Ein weiterer Vorteil ist, daß z.B. das ß-Hydroxyanthrachi- non nach der Reduktion aus der wäßrigen Mutterlauge durch Einstellen eines pH von 3 bis 4 praktisch quantitativ fällbar und ohne Reinigung mehrmals wieder einsatzfähig ist, während das 2-Hydroxy-3-chlornaphthochinon-(1,4) (entstanden während der Reduktion aus 2,3-Dichlornaphthochinon-(1,4)) durch eine aufwendige Abwasserreinigung beseitigt werden muß.Another advantage is that e.g. the ß-hydroxyanthraquinone after the reduction from the aqueous mother liquor by setting a pH of 3 to 4 can be precipitated practically quantitatively and can be used several times without purification, while the 2-hydroxy-3-chloronaphthoquinone- (1,4) (formed during the reduction from 2,3-dichloronaphthoquinone (1,4)) has to be eliminated by a complex wastewater treatment.
Die Einsatzmenge an Ahthrachinonen ist gering, sie liegt unter denen der Naphthochinonderivate. So ist z.B. ein Gewichtsverhältnis ß-Hydroxyanthrachinon zu o-Chlornitrobenzol von 0,003 bis 0,008, insbesondere 0,004 : 1 ausreichend, um auch das als Zwischenstufe auftretende Dichlorazoxybenzol über das Dichlorazobenzol gleichmäßig bis zur Hydrazoverbindung durchzureduzieren, während vom 2,3-Dichlornaphthochinon-(1,4) die doppelte Menge notwendig ist, um wenigstens beim ersten Einsatz der Edelmetallkatalysatoren vergleichbare Ergebnisse zu erzielen.The amount of ahthraquinones used is low, it is lower than that of the naphthoquinone derivatives. For example, a weight ratio of ß-hydroxyanthraquinone to o-chloronitrobenzene of 0.003 to 0.008, in particular 0.004: 1 is sufficient to evenly reduce the dichlorazoxybenzene which occurs as an intermediate via the dichlorazobenzene to the hydrazo compound, while of 2,3-dichloronaphthoquinone- (1,4) twice the amount is necessary in order to achieve comparable results at least when the noble metal catalysts are used for the first time.
Für die Wirtschaftlichkeit des Verfahrens ist von Bedeutung, daß der Edelmetallkatalysator - bei zuverlässiger Reproduzierbarkeit der Ausbeuten und Produkteigenschaften auch nach vielmaligem Einsatz - nur in einem Gewichtsverhältnis von Nitroverbindung zu Platin oder Palladium zwischen etwa 4000 : 1 und 1500 : 1, vorzugsweise 2500 : 1, eingesetzt zu werden braucht.For the economic viability of the process, it is important that the precious metal catalyst is more reliable Reproducibility of the yields and product properties even after repeated use - need only be used in a weight ratio of nitro compound to platinum or palladium between about 4000: 1 and 1500: 1, preferably 2500: 1.
Als Reaktionsmedium verwendet man eine 16 bis 25 %ige Natronlauge in der Menge, daß nach Reaktionsende durch das entstandene Reaktionswasser eine 10 bis 15 %ige Natronlaugekonzentration entsteht.A 16 to 25% sodium hydroxide solution is used as the reaction medium in such an amount that after the end of the reaction a 10 to 15% sodium hydroxide solution is formed by the water of reaction formed.
Auch hier zeigen die Anthrachinone gegenüber den Naphthochinonen Vorteile. Während mit Naphthochinon die besten Ergebnisse mit einer 16 %igen Natronlauge in einem Gewichtsverhältnis o-Nitrochlorbenzol zu NaOH (100 %) wie 1 : 0,095 erzielt werden, erlauben die Anthrachinone eine Erhöhung der NaOH-Konzentration bis auf 25 % und einen geringeren Einsatz von Natronlauge in einem Gewichtsverhältnis von o-Nitrochlorbenzol zu NaOH (100 %) wie 1 : 0,071, ohne daß dabei die Reaktionsgeschwindigkeit verlangsamt wird. Der Einsatz einer ca. 25 %igen NaOH bedeutet gegenüber einer 16 %igen NaOH nach obigen Gewichtsverhältnissen eine Verbesserung der Raumausbeute von ca. 20 %.Again, the anthraquinones show advantages over the naphthoquinones. While the best results are achieved with naphthoquinone with a 16% sodium hydroxide solution in a weight ratio of o-nitrochlorobenzene to NaOH (100%) such as 1: 0.095, the anthraquinones allow an increase in the NaOH concentration to 25% and a lower use of sodium hydroxide solution in a weight ratio of o-nitrochlorobenzene to NaOH (100%) such as 1: 0.071, without slowing down the reaction rate. The use of an approx. 25% NaOH means an improvement in the space yield of approx. 20% compared to a 16% NaOH according to the above weight ratios.
Die Reaktionstemperatur liegt bevorzugt zwischen 55 bis 60°C, der Wasserstoffdruck bevorzugt zwischen 1 bis 6 bar, wobei es vorteilhaft ist, den Druck während der Reduktion innerhalb der angegebenen Grenzwerte langsam steigen zu lassen.The reaction temperature is preferably between 55 to 60 ° C., the hydrogen pressure preferably between 1 to 6 bar, it being advantageous to let the pressure rise slowly within the specified limit values during the reduction.
Bei dem erfindungsgemäßen Verfahren wird die Reduktion von o-Nitrochlorbenzol zu 2,2'-Dichlorhydrazobenzol unter Verwendung eines mit Wasser nicht mischbaren Lösemittels, wie z.B. Benzol, Toluol, Xylol, Äthylbenzol oder deren technische Gemische, beispielsweise das unter dem Namen "Solventnaphtha" handelsübliche Gemisch aus m-Xylol und Äthylbenzol, durchgeführt.In the process according to the invention, the reduction of o-nitrochlorobenzene to 2,2'-dichlorohydrazobenzene is carried out using a water-immiscible solvent, such as e.g. Benzene, toluene, xylene, ethylbenzene or their technical mixtures, for example the mixture of m-xylene and ethylbenzene, which is commercially available under the name "Solventnaphtha".
Claims (6)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2733747A DE2733747C2 (en) | 1977-07-27 | 1977-07-27 | Process for the preparation of 2,2 dichlorohydrazobenzene |
| DE2733747 | 1977-07-27 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0000519A1 true EP0000519A1 (en) | 1979-02-07 |
| EP0000519B1 EP0000519B1 (en) | 1980-07-23 |
Family
ID=6014887
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP78100394A Expired EP0000519B1 (en) | 1977-07-27 | 1978-07-14 | Process for the preparation of 2,2'-dichlorohydrazobenzene |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US4217307A (en) |
| EP (1) | EP0000519B1 (en) |
| JP (1) | JPS5424838A (en) |
| CA (1) | CA1111449A (en) |
| DE (2) | DE2733747C2 (en) |
| IT (1) | IT1097303B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0007972A1 (en) * | 1978-07-31 | 1980-02-20 | Hüls Troisdorf Aktiengesellschaft | Process for the preparation of dichloro-hydrazobenzenes by catalytic hydrogenation of monochloro-nitrobenzenes |
| EP0391606A1 (en) * | 1989-04-05 | 1990-10-10 | Toyo Ink Manufacturing Co., Ltd. | Process for the production of an aromatic hydrazo compound |
| US5808154A (en) * | 1989-04-05 | 1998-09-15 | Toyo Ink Manufacturing Co., Ltd. | Process for the production of an aromatic hydrazo compound |
Families Citing this family (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4375559A (en) * | 1982-07-15 | 1983-03-01 | Air Products And Chemicals, Inc. | Process for the production of hydrazoaromatics using a multi-phase system |
| US20050037063A1 (en) * | 2003-07-21 | 2005-02-17 | Bolton Anthony E. | Combined therapies |
| EP1819681B1 (en) * | 2004-11-23 | 2009-08-12 | Warner-Lambert Company LLC | 7-(2h-pyrazol-3-yl)-3,5-dihydroxy-heptanoic acid derivatives as hmg co-a reductase inhibitors for the treatment of lipidemia |
| JP2006265129A (en) * | 2005-03-23 | 2006-10-05 | Air Water Inc | Method for producing 3,3'-bis(trifluoromethyl)hydrazobenzene |
| GT200600381A (en) | 2005-08-25 | 2007-03-28 | ORGANIC COMPOUNDS | |
| US7741317B2 (en) | 2005-10-21 | 2010-06-22 | Bristol-Myers Squibb Company | LXR modulators |
| US7888376B2 (en) | 2005-11-23 | 2011-02-15 | Bristol-Myers Squibb Company | Heterocyclic CETP inhibitors |
| US8383660B2 (en) | 2006-03-10 | 2013-02-26 | Pfizer Inc. | Dibenzyl amine compounds and derivatives |
| US7919506B2 (en) | 2006-03-10 | 2011-04-05 | Pfizer Inc. | Dibenzyl amine compounds and derivatives |
| CN101663262B (en) | 2006-12-01 | 2014-03-26 | 百时美施贵宝公司 | N- ( (3-benzyl) -2, 2- (bis-phenyl) -propan-1-amine derivatives as CETP inhibitors for the treatment of atherosclerosis and cardiovascular diseases |
| MX2015014666A (en) | 2013-04-17 | 2016-03-01 | Pfizer | N-piperidin-3-ylbenzamide derivatives for treating cardiovascular diseases. |
| WO2016055901A1 (en) | 2014-10-08 | 2016-04-14 | Pfizer Inc. | Substituted amide compounds |
| EP3911648A4 (en) | 2019-01-18 | 2022-10-26 | Astrazeneca AB | Pcsk9 inhibitors and methods of use thereof |
| CN111116407B (en) * | 2019-12-16 | 2022-02-22 | 浙江秦燕科技股份有限公司 | Method for preparing DCB reducing substance by continuous catalytic hydrogenation reduction |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2794046A (en) * | 1954-08-06 | 1957-05-28 | Allied Chem & Dye Corp | Method of reducing aromatic nitrogen compounds |
| US3156724A (en) * | 1962-10-25 | 1964-11-10 | Sterling Drug Inc | Preparation of 2, 2'-dichlorohydrazobenzene |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL131211C (en) * | 1965-04-05 |
-
1977
- 1977-07-27 DE DE2733747A patent/DE2733747C2/en not_active Expired
-
1978
- 1978-07-14 DE DE7878100394T patent/DE2860060D1/en not_active Expired
- 1978-07-14 EP EP78100394A patent/EP0000519B1/en not_active Expired
- 1978-07-25 IT IT26090/78A patent/IT1097303B/en active
- 1978-07-25 US US05/927,856 patent/US4217307A/en not_active Expired - Lifetime
- 1978-07-26 JP JP9056478A patent/JPS5424838A/en active Granted
- 1978-07-26 CA CA308,185A patent/CA1111449A/en not_active Expired
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2794046A (en) * | 1954-08-06 | 1957-05-28 | Allied Chem & Dye Corp | Method of reducing aromatic nitrogen compounds |
| US3156724A (en) * | 1962-10-25 | 1964-11-10 | Sterling Drug Inc | Preparation of 2, 2'-dichlorohydrazobenzene |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0007972A1 (en) * | 1978-07-31 | 1980-02-20 | Hüls Troisdorf Aktiengesellschaft | Process for the preparation of dichloro-hydrazobenzenes by catalytic hydrogenation of monochloro-nitrobenzenes |
| EP0391606A1 (en) * | 1989-04-05 | 1990-10-10 | Toyo Ink Manufacturing Co., Ltd. | Process for the production of an aromatic hydrazo compound |
| US5808154A (en) * | 1989-04-05 | 1998-09-15 | Toyo Ink Manufacturing Co., Ltd. | Process for the production of an aromatic hydrazo compound |
Also Published As
| Publication number | Publication date |
|---|---|
| EP0000519B1 (en) | 1980-07-23 |
| US4217307A (en) | 1980-08-12 |
| IT1097303B (en) | 1985-08-31 |
| IT7826090A0 (en) | 1978-07-25 |
| DE2860060D1 (en) | 1980-11-13 |
| JPS5424838A (en) | 1979-02-24 |
| DE2733747C2 (en) | 1979-09-27 |
| DE2733747B1 (en) | 1979-02-08 |
| JPS627908B2 (en) | 1987-02-19 |
| CA1111449A (en) | 1981-10-27 |
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