US3577457A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for preparing 4,4'-dicarboxybenzophenone
Assignee: Gulf Research and Development Co
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Filing: 1968-07-19
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Granted: 1971-05-04
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Expires: 1988-07-19
Abstract
Abstract A PROCESS FOR PREPARING PURIFIED 4,4''-DICARBOXYBENZOPHENONE WHICH INVOLVES TREATING A MIXTURE CONTAINING 4,4''DICARBOXYBENZOPHENEONE AND IMPURITIES WITH METHANOL OR ETHYLENE GLYCOL AT A TEMPERATURE BELOW ABOUT 85*C., WHEREBY THE 4,4''-DICARBOXYBENZXOPHENONE REMAINS UNAFFECTED BUT THE IMPURITIES ARE REMOVED.
Inventors
- 👤 Johann G D Schulz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:39
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/16; C07C51/27; C07C51/275; C07C51/42; C07C51/47
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-03 | 1974-11-02 | 1975-05-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-03 | 1978-11-02 | 1979-05-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-03 | 1982-11-02 | 1983-05-04 | $7700.00 | Window Closed / Lapsed |