US2863914A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for converting phthalic acid into terephthalic acid
Assignee: Henkel AG and Co KGaA
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Filing: 1957-01-24
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Granted: 1958-12-09
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Expires: 1977-01-24
Abstract
No abstract record available.
Inventors
- 👤 Raecke Bernhard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:01
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/41; C07C51/416
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
71 words
IN A PROCESS OF CONVERTING COMPOUNDS OF THE GROUP CONSISTING OF PHTHALIC ACID AND ISOPHTHALIC ACID INTO TEREPHTHALIC ACID, THE STEP OF HEATING A DIALKALI METAL SALT OF A COMPOUND OF THE GROUP CONSISTING OF PHTHALIC ACID AND ISOPHTHALIC ACID TO A TEMPERATURE BETWEEN 340*C. AND 500*C., IN A SUBSTANTIALLY OXYGEN-FREE INERT ATMOSPHERE, THEREBY CAUSING REARRANGEMENT OF A PORTION OF THE PHTHALIC ACID RADICALS OF SAID SALTS INTO TEREPHTHALIC ACID RADICALS.
Claim 2
Dependent Claim
71 words
IN A PROCESS OF CONVERTING COMPOUNDS OF THE GROUP CONSISTING OF PHTHALIC ACID AND ISOPHTHALIC ACID INTO TEREPHTHALIC ACID, THE STEP OF HEATING A DIALKALI METAL SALT OF A COMPOUND OF THE GROUP CONSISTING OF PHTHALIC ACID AND ISOPHTHALIC ACID TO A TEMPERATURE BETWEEN 340*C. AND 500*C., IN A SUBSTANTIALLY OXYGEN-FREE INERT ATMOSPHERE, THEREBY CAUSING REARRANGEMENT OF A PORTION OF THE PHTHALIC ACID RADICALS OF SAID SALTS INTO TEREPHTHALIC ACID RADICALS.
References Cited (Backward Citations)
US1937477A
Cited
BE522829A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-12-08 | 1962-06-09 | 1962-12-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-12-08 | 1966-06-09 | 1966-12-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-12-08 | 1970-06-09 | 1970-12-09 | $7700.00 | Window Closed / Lapsed |