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US3868403A
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Process for the production of halogen-substituted aromatic amines
Assignee: Bayer AG
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Filing: 1971-07-19
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Granted: 1975-02-25
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Expires: 1991-07-19
Abstract
Abstract Halogen substituted aromatic amines are prepared by reducing the corresponding nitro compounds at a temperature of from 80* 130* C, under hydrogen pressure of from 10 - 150 atmospheres and at a pH of from 7 - 12 in an amount of watermisicible solvent sufficient to maintain a homogeneous phase during the reaction in the presence of from 1 to 25 percent by weight of a noble metal catalyst supported on active carbon, which catalyst has been used at least once in a catalytic hydrogenation reaction.
Inventors
- 👤 Hans-Joachim Becker
- 👤 Helmut Dierichs
- 👤 Walter Schmidt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 19:27
CPC Classifications
C; C07; C07C; C07C209/00; C07C209/30; C07C209/32; C07C209/36; C07C209/365; F; F16; F16D; F16D65/00; F16D65/02; F16D2065/026
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
114 words
IN A PROCESS FOR PREPARING HALOGEN SUBSTITUTED AROMATIC AMINES FROM THE CORRESPONDING NITRO COMPOUNDS BY HYDROGEN REDUCTION IN THE PRESENCE OF A NOBLE METAL CATALYST THE IMPROVEMENT WHICH CONSISTS ESSENTIALLY OF CARRYING OUT SAID REDUCTION AT A PH OF FROM 7-12 IN THE PRESENCE OF A NOBLE METAL CATALYST HAVING A METAL CONTENT OF FROM 0.1 TO 5% BY WEIGHT AND A PREDETERMINED LEVEL OF ACTIVITY THROUGH HAVING BEEN PERVIOUSLY USED AT LEAST ONCE IN A CATALYTIC HYDROGENATION REACTION, SAID PREVIOUSLY USED CATALYST PRODUCING SAID HALOGEN SUBSTITUTED AROMATIC AMINES IN SUBSTITANTIALLY QUANTITATIVE YIELD WITH SUBSTANTIALLY NO DEHALOGENATION AND THE FORMATION OF SUBSTANTIALLY NO SECONDARY PRODUCTS AS COMPARED TO THE SAME FRESH NOBLE METAL CATALYST.
Claim 2
Dependent Claim
114 words
IN A PROCESS FOR PREPARING HALOGEN SUBSTITUTED AROMATIC AMINES FROM THE CORRESPONDING NITRO COMPOUNDS BY HYDROGEN REDUCTION IN THE PRESENCE OF A NOBLE METAL CATALYST THE IMPROVEMENT WHICH CONSISTS ESSENTIALLY OF CARRYING OUT SAID REDUCTION AT A PH OF FROM 7-12 IN THE PRESENCE OF A NOBLE METAL CATALYST HAVING A METAL CONTENT OF FROM 0.1 TO 5% BY WEIGHT AND A PREDETERMINED LEVEL OF ACTIVITY THROUGH HAVING BEEN PERVIOUSLY USED AT LEAST ONCE IN A CATALYTIC HYDROGENATION REACTION, SAID PREVIOUSLY USED CATALYST PRODUCING SAID HALOGEN SUBSTITUTED AROMATIC AMINES IN SUBSTITANTIALLY QUANTITATIVE YIELD WITH SUBSTANTIALLY NO DEHALOGENATION AND THE FORMATION OF SUBSTANTIALLY NO SECONDARY PRODUCTS AS COMPARED TO THE SAME FRESH NOBLE METAL CATALYST.
Claim 3
Dependent Claim
11 words
Process of claim 1 wherein said nitro compound has the formula
Claim 4
Dependent Claim
36 words
Process of claim 1 wherein said nitro compound is selected from the group of 4-chloronitrobenzene; 4-chloronitrotoluene; 4-chloro-2-nitro-1,3-dimethylbenzene; 4-fluoronitrobenzene; 4-bromonitrobenzene; 3,4-dichloronitrobenzene; 2,3,4-trichloronitrobenzene; 3,4-dibromonitrobenzene; 3-chloro-4-bromonitrobenzene; 2,6-dichloro-4-nitrophenol; 4-chloro-2-nitroanisole; 4-chloro-1-nitronaphthalene; 4-chloro-2,6-dinitrobenzene; 4-chloro-3,5-dinitrobenzoic acid or an ester thereof; 3-chloro-3''-nitrodiphenyl; and 2-chloro-4-nitroaniline.
Claim 5
Dependent Claim
84 words
Process of claim 1 wherein the hydrogen reduction is carried out at a temperature of from 80* to 130C under a hydrogen pressure of from 10 to 150 atmospheres in an amount of a water-miscible solvent sufficient to maintain the nitro compounds and the amines formed in the homogeneous phase throughout the reaction, said catalyst being supported on active carbon and having a metal content of 0.1 to 5% by weight and being used in an amount of from 1 to 25% by weight.
Claim 6
Dependent Claim
21 words
Process of claim 4 wherein said temperature is from 100*-110* C and said hydrogen pressure is from 80 - 100 atmospheres.
Claim 7
Dependent Claim
8 words
Process of claim 4 is carried out continuously.
Claim 8
Dependent Claim
14 words
Process of claim 4 wherein said solvent is a mixture of isopropanol and water.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-24 | 1978-08-26 | 1979-02-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-24 | 1982-08-26 | 1983-02-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-24 | 1986-08-26 | 1987-02-25 | $7700.00 | Window Closed / Lapsed |