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Patent US2439905A successfully refreshed from Google Patents.
US2439905A
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US
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Process of purifying lactones
Assignee: Nopco Chemical Co
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Filing: 1943-05-05
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Granted: 1948-04-20
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Expires: 1963-05-05
Abstract
No abstract record available.
Inventors
- 👤 Frank D Pickel
- 👤 Louis T Rosenberg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 08:52
CPC Classifications
C; C07; C07D; C07D307/00; C07D307/02; C07D307/26; C07D307/30; C07D307/32; C07D307/33
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2092494A
Cited
US2151990A
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US2194665A
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US2271872A
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US2319545A
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US2328000A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1951-04-20 | 1951-10-20 | 1952-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1955-04-20 | 1955-10-20 | 1956-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1959-04-20 | 1959-10-20 | 1960-04-20 | $7700.00 | Window Closed / Lapsed |