Patent US5272239A successfully refreshed from Google Patents.
US2996546A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of purifying benzidines
Assignee: Carwin Co
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Filing: 1958-01-14
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Granted: 1961-08-15
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Expires: 1978-01-14
Abstract
No abstract record available.
Inventors
- 👤 Adnan A R Sayigh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:52
CPC Classifications
C; C07; C07C; C07C211/00; C07C211/43; C07C211/54
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
16 words
THE METHOD OF PURIFYING IMPURE MINERAL ACID SALTS OF A COMPOUND CORRESPONDING TO THE FOLLOWING FORMULA:
Claim 2
Independent Claim
16 words
THE METHOD OF PURIFYING IMPURE MINERAL ACID SALTS OF A COMPOUND CORRESPONDING TO THE FOLLOWING FORMULA:
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) | 1964-08-14 | 1965-02-13 | 1965-08-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-08-14 | 1969-02-13 | 1969-08-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-08-14 | 1973-02-13 | 1973-08-15 | $7700.00 | Window Closed / Lapsed |