US3726927A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Aromatic sulphones
Assignee: Imperial Chemical Industries Ltd
•
Filing: 1970-07-20
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Granted: 1973-04-10
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Expires: 1990-07-20
Abstract
Abstract A 4-(4-halophenylsulphonyl)biphenyl (halogen being Cl or F) is a valuable intermediate for preparing aromatic sulphones which are useful as starting materials for polymerization reactions to give polysulphones containing biphenyl residues in the polymer chain.
Inventors
- 👤 V Leslie
- 👤 J Rose
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 12:10
CPC Classifications
C; C07; C07C; C07C317/00; C07C317/14; C07F; C07F9/00; C07F9/02; C07F9/28; C08; C08G; C08G65/00; C08G65/34; C08G65/38; C08G75/00; C08G75/20
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
US2998454A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-09 | 1976-10-09 | 1977-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-09 | 1980-10-09 | 1981-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-09 | 1984-10-09 | 1985-04-10 | $7700.00 | Window Closed / Lapsed |