US2491116A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Friedel-crafts type catalyst complexes and their preparation
Assignee: Standard Oil Development Co
•
Filing: 1945-08-29
•
Granted: 1949-12-13
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Expires: 1965-08-29
Abstract
No abstract record available.
Inventors
- 👤 Charles A Kraus
- 👤 John D Calfee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:23
CPC Classifications
B; B01; B01J; B01J27/00; B01J27/06; Y; Y10; Y10S; Y10S260/00; Y10S260/25
Claims Analysis
Total Claims: 0
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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) | 1952-12-12 | 1953-06-13 | 1953-12-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1956-12-12 | 1957-06-13 | 1957-12-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1960-12-12 | 1961-06-13 | 1961-12-13 | $7700.00 | Window Closed / Lapsed |