Patent US4634376A successfully refreshed from Google Patents.
Patent US2251835A successfully refreshed from Google Patents.
US2251835A
Expired / Lapsed
US
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Production of tetrahydrofurane from 1,4-butylene glycol
Assignee: GAF Chemicals Corp
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Filing: 1940-04-19
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Granted: 1941-08-05
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Expires: 1960-04-19
Abstract
No abstract record available.
Inventors
- 👤 Reppe Walter
- 👤 Trieschmann Hans-Georg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 19:31
CPC Classifications
C; C07; C07D; C07D307/00; C07D307/02; C07D307/04; C07D307/06; C07D307/08
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1944-08-04 | 1945-02-03 | 1945-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1948-08-04 | 1949-02-03 | 1949-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1952-08-04 | 1953-02-03 | 1953-08-05 | $7700.00 | Window Closed / Lapsed |