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US3781319A
Expired / Lapsed
US
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Process for preparing isocyanates
Assignee: University of Iowa
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Filing: 1970-09-28
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Granted: 1973-12-25
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Expires: 1990-09-28
Abstract
Abstract ISOCYANATES ARE PREPARED BY PYROLYZING AN AMINIMIDE HAVING THE FORMULA R-(CO-N(-)-N(+)(-R1)(-R2)-R3)N WHEREIN R1, R2 AND R3 ARE ALKYL, ARYL AND RADICALS IN WHICH R2 AND R3 ARE JOINED TO FORM A HETEROCYCLIC RING, R IS AN ALIPHATIC, CYCLOALIPHATIC OR AROMATIC GROUPS AND N IS AN INTEGER OF AT LEAST 1, USUALLY 1 TO 4.
Inventors
- 👤 S Wawzonek
- 👤 R Gueldner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 03:12
CPC Classifications
C; C07; C07D; C07D207/00; C07D207/46; C07D207/50; C07C; C07C263/00; C07C263/12
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) | 1976-12-24 | 1977-06-25 | 1977-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-24 | 1981-06-25 | 1981-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-24 | 1985-06-25 | 1985-12-25 | $7700.00 | Window Closed / Lapsed |