US3554872A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for separation of 2,6-tolylene diisocyanate from isomeric mixtures
Assignee: Wyeth Holdings LLC
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Filing: 1968-07-24
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Granted: 1971-01-12
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Expires: 1988-07-24
Abstract
Abstract A PROCESS FOR SEPARATING 2,6-TOLYLENE DIISOCYANATE FROM A MIXUTRE CONTAINING 2,4-TOLYLENE DISSOCYANATE AND AT LEAST 10% OF 2.6-TOLYLENE DIISOCYANATE BY (1) REACTING SAID MIXUTRE WITH A HYDROXYL-TERMINATED POLYESTER OR POLYETHER AND (2) SUBSEQUENTLY VACUUM DISTILLING TO OBTAIN PURE 2,6-TOYLENE DIISOCYANATE OR AN ISOMER MIXUTRE RICHER IN THIS COMPONENT THAN WAS THE STARTING MATERIAL.
Inventors
- 👤 Eugene Yue Chieh Chang
- 👤 Samuel Kaizerman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 13:25
CPC Classifications
C; C08; C08G; C08G18/00; C08G18/06; C08G18/70; C08G18/72; C08G18/74; C08G18/76; C08G18/7614; C08G18/7621; C07; C07C; C07C263/00; C07C263/18; C07C263/20; C08G18/28; C08G18/40; C08G18/42; C08G18/4236; C08G18/4238; C08G18/48; C08G18/4825
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) | 1974-01-11 | 1974-07-13 | 1975-01-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-11 | 1978-07-13 | 1979-01-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-11 | 1982-07-13 | 1983-01-12 | $7700.00 | Window Closed / Lapsed |