US3631067A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of coumarin
Assignee: Dow Chemical Co
•
Filing: 1970-01-05
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Granted: 1971-12-28
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Expires: 1990-01-05
Abstract
Abstract IN THE PROCESS FOR PREPARING COUMARIN BY REACTING SALICYLALDEHYDE WITH AN ALKALI METAL ACETATE AND ACETIC ANHYDRIDE, SEPARATION OF THE PRODUCT IS IMPROVED WITHOUT DETRIMENTALLY AFFECTING THE YIELD BY MAINTAINING THE MOLAR CONCENTRATION OF ALIALI METAL ACETATE AT OR BELOW THE CONCENTRATION OF THE TOTAL SALICYLALDEHYDE EMPLOYED IN THE REACTION AND THEN SEPARATING THE COUMARIN FROM THE REACTION MIXTURE BY DISTILLATION.
Inventors
- 👤 Robert J Nankee
- 👤 Charles F Fosberry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 03:38
CPC Classifications
C; C07; C07D; C07D311/00; C07D311/02; C07D311/04; C07D311/06; C07D311/08; C07D311/10
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) | 1974-12-27 | 1975-06-28 | 1975-12-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-27 | 1979-06-28 | 1979-12-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-27 | 1983-06-28 | 1983-12-28 | $7700.00 | Window Closed / Lapsed |