US2823228A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the transformation of di-
Assignee: —
•
Filing: —
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Granted: 1958-02-11
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Expires: 1975-02-11
Abstract
No abstract record available.
Inventors
No inventors recorded.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 01:02
CPC Classifications
—
Claims Analysis
Total Claims: 1
Claim 1
Independent Claim
101 words
THE PROCESS OF PRODUCING 4,4''-DIPHENYL-DICARBOXYLIC ACID WHICH COMPRISES HEATING AN ALKALI METAL SALT OF DIPHENIC ACID TO A TEMPERATURE ABOVE ABOUT 340*C. AND BELOW THE TEMPERATURE AT WHICH SUBSTANTIAL DECOMPOSITION OF THE STARTING MATERIAL TAKES PLACE IN A SUBSTANTIALLY OXYGEN-FREE ATMOSPHERE OF AN INERT GAS SELECTED FROM THE GROUP CONSISTING OF CARBON DIOXIDE AND NITROGEN AND IN THE PRESENCE OF A CATALYST CONTAINING A METAL FROM THE GROUP CONSISTING OF CADMIUM, ZINC, IRON AND LEAD UNTIL AN ALKALI METAL SALT OF 4,4''-DIPHENYL-DICARBOXYLIC ACID FORMED, TRANSFORMING THE 4,4''-DIPHENYL-DICARBOXYLIC ACID SALT INTO 4,4''-DIPHENYL-DICARBOXYLIC ACID, AND SEPARATING THE 4,4''-DIPEHNYL-DICARBOXYLIC ACID FROM THE REACTION MIXTURE.
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) | 1961-02-10 | 1961-08-12 | 1962-02-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-02-10 | 1965-08-12 | 1966-02-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-02-10 | 1969-08-12 | 1970-02-11 | $7700.00 | Window Closed / Lapsed |