Patent US2833824A successfully refreshed from Google Patents.
US2833824A
Expired / Lapsed
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Purification of n, n'-diphenyl-p-phenylenediamine
Assignee: F Hoffmann La Roche AG
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Filing: 1956-04-10
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Granted: 1958-05-06
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Expires: 1976-04-10
Abstract
No abstract record available.
Inventors
- 👤 Pecherer Benjamin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 15:27
CPC Classifications
C; C10; C10M; C10M133/00; C10M133/02; C10M133/04; C10M133/12; C10M2215/00; C10M2215/02; C10M2215/06; C10M2215/066; C10N; C10N2030/00; C10N2030/10
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
31 words
A PROCESS FOR THE PURIFICATION OF N,N''-DIPHENYL-PPHENYLENEDIAMINE WHICH COMPRISES PERCOLATING A SOLUTION COMPRISING IMPURE N,N''-DIPHENYL-P-PHENYLENEDIAMINE IN AN INERT ORGANIC SOLVENT THROUGH ACID ACTIVATED, BASIC MAGNESIUM ALUMINUM SILICATE IN AN INERT ATMOSPHERE.
Claim 2
Dependent Claim
31 words
A PROCESS FOR THE PURIFICATION OF N,N''-DIPHENYL-PPHENYLENEDIAMINE WHICH COMPRISES PERCOLATING A SOLUTION COMPRISING IMPURE N,N''-DIPHENYL-P-PHENYLENEDIAMINE IN AN INERT ORGANIC SOLVENT THROUGH ACID ACTIVATED, BASIC MAGNESIUM ALUMINUM SILICATE IN AN INERT ATMOSPHERE.
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) | 1961-05-05 | 1961-11-04 | 1962-05-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-05-05 | 1965-11-04 | 1966-05-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-05-05 | 1969-11-04 | 1970-05-06 | $7700.00 | Window Closed / Lapsed |