US4307249A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the selective preparation of p-aminophenol from nitrobenzene
Assignee: Mallinckrodt Chemical Inc
•
Filing: 1981-01-07
•
Granted: 1981-12-22
•
Expires: 2001-01-07
Abstract
Abstract An improved process for preparing p-aminophenol by the catalytic hydrogenation of nitrobenzene in an aqueous acidic reaction medium containing a dimethylalkylamine oxide whereby the hydrogenation rate is increased and the selectivity of the reaction for p-aminophenol is improved.
Inventors
- 👤 Edward L. Derrenbacker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 04:25
CPC Classifications
C; C07; C07C; C07C215/00; C07C215/74; C07C215/76
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
31 words
A method for preparing p-aminophenol, by the catalytic hydrogenation of nitrobenzene in an acidic aqueous reaction medium containing dimethylalkylamine oxide wherein said alkyl group contains from 8 to 20 carbon atoms.
Claim 2
Independent Claim
31 words
A method for preparing p-aminophenol, by the catalytic hydrogenation of nitrobenzene in an acidic aqueous reaction medium containing dimethylalkylamine oxide wherein said alkyl group contains from 8 to 20 carbon atoms.
Claim 3
Dependent Claim
15 words
The method of claim 1 wherein 50% or more of the alkyl groups are n-dodecyl.
Claim 4
Dependent Claim
15 words
The method of claim 2 wherein 95% or more of the alkyl groups are n-dodecyl.
Claim 5
Dependent Claim
12 words
The method of claim 1 wherein the catalyst comprises platinum on carbon.
Claim 6
Dependent Claim
14 words
The method of claim 4 wherein the reaction medium is acidified with sulfuric acid.
Claim 7
Dependent Claim
22 words
The method of claim 5 wherein from 0.1 to 0.4% by volume of dimethylalkylamine oxide, based on the aqueous medium, is used.
Claim 8
Dependent Claim
22 words
The method of claim 6 wherein from 0.2 to 0.3% by volume of dimethylalkylamine oxide, based on the aqueous medium, is used.
Claim 9
Dependent Claim
20 words
The method of claim 7 wherein about 0.25% by volume of dimethylalkylamine oxide, based on the aqueous medium, is used.
Claim 10
Dependent Claim
22 words
The method of claim 3 wherein the catalyst comprises platinum on carbon and wherein the reaction medium is acidified with sulfuric acid.
Claim 11
Dependent Claim
20 words
The method of claim 9 wherein about 0.25% by volume of dimethylalkylamine oxide, based on the aqueous medium, is used.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-12-21 | 1985-06-22 | 1985-12-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-12-21 | 1989-06-22 | 1989-12-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-12-21 | 1993-06-22 | 1993-12-22 | $7700.00 | Window Closed / Lapsed |