Patent US3810937A successfully refreshed from Google Patents.
US3810937A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Purification of carboxylic acids
Assignee: CP HALL COMPANY
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Filing: 1970-09-15
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Granted: 1974-05-14
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Expires: 1990-09-15
Abstract
Abstract DICARBOXYLIC ACIDS IN WATER SOLUTIONS ARE PURIFIED AND RECOVERED BY WATER-IMMISCIBLE SOLVENTS. THE SOLVENT SOLUTIONS OF DICARBOXYLIC ACIDS ARE TREATED IN VARIOUS WAYS TO RECOVER, SEPARATE, AND PURIFY DICARBOXYLIC ACIDS. THE AQUEOUS PHASE REMAINING BY EXTRACTION OF DICARBOXYLIC ACIDS MAY BE RE-USED BY CYCLING BACK TO THE PROCESS IN ORDER TO RECOVER ECONOMIC VALUES OF REACTANTS AND CATALYTSTS AND TO AVOID BUILDUP OF POLLUTING BLEEDSTREAMS. SOLVENTS AND ALCOHOLS ARE RECOVERED FROM AQUEOUS AND/OR NON-AQUEOUS PHASES AND ARE RECYCLED IN THE PROCESS.
Inventors
- 👤 V Kuceski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:30
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/42; C07C51/48
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) | 1977-05-13 | 1977-11-12 | 1978-05-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-13 | 1981-11-12 | 1982-05-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-13 | 1985-11-12 | 1986-05-14 | $7700.00 | Window Closed / Lapsed |