Patent US2455314A successfully refreshed from Google Patents.
US2455314A
Expired / Lapsed
US
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Fractional condensation of phthalic anhydride
Assignee: Wyeth Holdings LLC
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Filing: 1945-08-21
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Granted: 1948-11-30
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Expires: 1965-08-21
Abstract
No abstract record available.
Inventors
- 👤 Kurt F Pietzsch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 10:14
CPC Classifications
B; B01; B01D; B01D7/00; B01D7/02; C; C07; C07C; C07C51/00; C07C51/54; C07C51/573
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2064468A
Cited
US2076033A
Cited
US2219333A
Cited
US2071329A
Cited
US2215968A
Cited
US2283209A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1951-11-30 | 1952-05-31 | 1952-11-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1955-11-30 | 1956-05-31 | 1956-11-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1959-11-30 | 1960-05-31 | 1960-11-30 | $7700.00 | Window Closed / Lapsed |