US3576875A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for isolating 4,4'-diamino diphenylmethane from polyphenylmethylene polyamine mixtures
Assignee: Bayer AG
•
Filing: 1968-03-26
•
Granted: 1971-04-27
•
Expires: 1988-03-26
Abstract
Abstract A PROCESS FOR ISOLATING 4,4''-DIAMINO DIPHENYLEMTHANE FROM A POLYPHENYLMETHYLENE POLYAMINE MIXTURE COMPRISES REACTING THE POLYAMINE MIXTURE WITH AN ALKALI METAL OR ALKALINE EARTH METAL HALIDE, CYANIDE OR THIOCYANATE AND DECOMPOSING THE RESULTING ADDUCT FORMED.
Inventors
- 👤 Ernst-Heinrich Rohe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 03:13
CPC Classifications
C; C07; C07C; C07C211/00; C07C211/43; C07C211/44; C07C211/49; C07C211/50; C07C209/00; C07C209/68; C07C209/78; C07C209/82; C07C209/84
Claims Analysis
Total Claims: 0
No claims parsed yet. Click Sync Now above to re-index claims from Google Patents.
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) | 1974-04-26 | 1974-10-26 | 1975-04-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-26 | 1978-10-26 | 1979-04-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-26 | 1982-10-26 | 1983-04-27 | $7700.00 | Window Closed / Lapsed |