US2923736A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Purification of carboxylic acids
Assignee: Imperial Chemical Industries Ltd
•
Filing: 1957-11-18
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Granted: 1960-02-02
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Expires: 1977-11-18
Abstract
No abstract record available.
Inventors
- 👤 Maclean Duncan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 06:51
CPC Classifications
B; B01; B01J; B01J8/00; B01J8/18; B01J8/24
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
67 words
IN A PROCESS FOR THE PURIFICATION OF TEREPHTHALIC ACID BY SUBLIMATION, THE IMPROVEMENT WHICH COMPRISES PASSING AN INERT GAS THROUGH A BED OF CRUDE TEREPHTHALIC ACID UNDER FLUIDIZING CONDITIONS AT A TEMPERATURE OF AT LEAST 300* C., WHEREBY SAID TEREPHTHALIC ACID IS EVAPORATED AND ENTRAINED IN SAID INERT GAS ALONG WITH SUBLIMED IMPURITIES AND THEREAFTER FRACTIONALLY CONDENSING THE SUBLIMATE AT A TEMPERATURE GREATER THAN 150* AND C.
Claim 2
Dependent Claim
67 words
IN A PROCESS FOR THE PURIFICATION OF TEREPHTHALIC ACID BY SUBLIMATION, THE IMPROVEMENT WHICH COMPRISES PASSING AN INERT GAS THROUGH A BED OF CRUDE TEREPHTHALIC ACID UNDER FLUIDIZING CONDITIONS AT A TEMPERATURE OF AT LEAST 300* C., WHEREBY SAID TEREPHTHALIC ACID IS EVAPORATED AND ENTRAINED IN SAID INERT GAS ALONG WITH SUBLIMED IMPURITIES AND THEREAFTER FRACTIONALLY CONDENSING THE SUBLIMATE AT A TEMPERATURE GREATER THAN 150* AND C.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1963-02-01 | 1963-08-03 | 1964-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1967-02-01 | 1967-08-03 | 1968-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1971-02-01 | 1971-08-03 | 1972-02-02 | $7700.00 | Window Closed / Lapsed |