US3661982A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dicarboxylic acid salts of trans,trans 4,4'-diaminodicyclohexylmethane
Assignee: Imperial Chemical Industries Ltd
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Filing: 1968-05-17
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Granted: 1972-05-09
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Expires: 1988-05-17
Abstract
Abstract PROCESS FOR THE SEPARATION OF TRANS-TRANS RICH SALTS OF 4,4''-DIAMINODICYCLOHEXYLMETHANE AND DICARBOXYLIC ACID BY THEIR PREFERENTIAL INSOLUBILITY IN METHANOL OR BENZYL ALCOHOL OVER SIMILAR SALTS OF THE OTHER GEOMETRICAL ISOMERS OF 4,4'' - DIAMINODICYCLOHEXYLMETHANE. TEGENERATION OF TRANS-TRANS ENRICHED 4,4'' - DIMINODICYCLOHEXYLMETHANE THEREFROM. THE SALTS ESPECIALLY THE DODECANEDIOIC ACID SALT MAY BE USED FOR THE MANUFACTURE OF POLYAMIDES. OTHER SOLVENTS MAY BE USED IN CONJUNCTION WITH METHANOL OR BENZYL ALCOHOL.
Inventors
- 👤 Geoffrey Ernest Beswick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-10 02:20
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/09; C07C209/00; C07C209/82; C07C209/84; C07C209/86; C07C211/00; C07C211/01; C07C211/02; C07C211/09; C07C211/12; C07C211/33; C07C211/34; C07C211/36
Claims Analysis
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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) | 1975-05-09 | 1975-11-08 | 1976-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-09 | 1979-11-08 | 1980-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-09 | 1983-11-08 | 1984-05-09 | $7700.00 | Window Closed / Lapsed |