US3565768A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for refining 4,4'-methylenebis (cyclohexyl isocyanate)
Assignee: Bayer Corp
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Filing: 1968-04-19
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Granted: 1971-02-23
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Expires: 1988-04-19
Abstract
Abstract CRUDE 4,4''-METHYLENEBIS (CYCLOHEXYL ISOCYANATE) IS REFINED BY (1) REMOVING MOST OF THE PHOSGENATION SOLVENT BY DISTILLATION AT LESS THAN ABOUT 180*C., (2) CONTINUING SOLVENT DISTILLATION AT HIGHER TEMPERATURES, (3) REMOVING A MINOR AMOUNT OF THE 4,4''-METHYLENEBIS(CYCLOHEXYL ISOCYANATE) BY DISTILLATION AT A PRESSURE BELOW ABOUT 3 MM. HG IS EQUIPMENT PROVIDING A LIMITED RESIDENCE TIME, AND (4) DISTILLING THE BULK OF THE 4,4''-METHYLENEBIS(CYCLOHEXYL ISOCYANATE) FROM STAGE (3) AT A PRESSURE NOT EXCEEDING 1.0 MM. HG.
Inventors
- 👤 Benton Robinson Grant Jr
- 👤 Carl Francis Irwin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 12:14
CPC Classifications
C; C07; C07C; C07C263/00; C07C263/18; C07C263/20; C07C2601/00; C07C2601/12; C07C2601/14
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) | 1974-02-22 | 1974-08-24 | 1975-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-22 | 1978-08-24 | 1979-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-22 | 1982-08-24 | 1983-02-23 | $7700.00 | Window Closed / Lapsed |