US3792024A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Polymerization of benzimidazobenzophenanthroline-ladder polymer
Assignee: Celanese Corp
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Filing: 1972-07-27
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Granted: 1974-02-12
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Expires: 1992-07-27
Abstract
Abstract AN IMPROVED METHOD OF FORMING A BENZIMIDAZOBENZOPHENTANTHROLINE-LADDER POLYMER IS DISCLOSED. AN ORGANIC TETRAAMINE (E.G., 1,2,4,5-TETRAAMINOBENZENE) AND A TETRACARBOXYLIC ACID DIANHYDRIDE (E.G., 1,4,5,8-NAPTHALENE DIANHYDRIDE) ARE REACTED IN A POLYPHOSPHERIC ACID SOLVENT IN THE PRESENCE OF A CATALYTICALLY EFFECTIVE AMOUNT OF A METAL CATION-CONTAINING LEWIS ACID (E.G., ANTIMONY TRICHLORIDE) TO FORM THE POLYMER.
Inventors
- 👤 L Saferstein
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:23
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/0666; C08G73/0677
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) | 1977-02-11 | 1977-08-13 | 1978-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-11 | 1981-08-13 | 1982-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-11 | 1985-08-13 | 1986-02-12 | $7700.00 | Window Closed / Lapsed |