US2741633A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Separation of isophthalic and terephthalic acids
Assignee: Union Oil Company of California
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Filing: 1952-11-17
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Granted: 1956-04-10
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Expires: 1972-11-17
Abstract
No abstract record available.
Inventors
- 👤 Art C Mckinnis
- 👤 John L Bills
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 23:36
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/42; C07C51/48
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
99 words
A PROCESS FOR SEPARATING A MIXTURE OF ISOPHTHALIC ACID AND TEREPHTALIC ACID WHICH COMPRISES EXTRACTING SAID MIXTURE AT A TEMPERATURE BETWEEN 50* C. AND 150* C. WITH A SOLVENT CONSISTING ESSENTIALLY OF BETWEEN 65% AND 95% OF AN ALIPHATIC WATER-SOLUBLE ALCOHOL AND BETWEEN 5% AND 35% OF WATER, SAID ALCOHOL BEING SELECTED FROM THE CLASS CONSISTING OF MONO- AND DI-HYDROXY ALKANES CONTAINING FROM 1 TO 3 CARBON ATOM S, CONTINUING SAID EXTRACTION UNTIL SUBSTANTIALLY PURE TERPHATALIC ACID REMAINS AS RESIDUE, SEPARATING AN EXTRACT RICH IN ISOPHATHALIC ACID FROM SAID TEREPHTHALIC ACID RESIDUE, AND RECOVERING ISOPHTHALIC ACID FROM SAID EXTRACT.
Claim 2
Dependent Claim
99 words
A PROCESS FOR SEPARATING A MIXTURE OF ISOPHTHALIC ACID AND TEREPHTALIC ACID WHICH COMPRISES EXTRACTING SAID MIXTURE AT A TEMPERATURE BETWEEN 50* C. AND 150* C. WITH A SOLVENT CONSISTING ESSENTIALLY OF BETWEEN 65% AND 95% OF AN ALIPHATIC WATER-SOLUBLE ALCOHOL AND BETWEEN 5% AND 35% OF WATER, SAID ALCOHOL BEING SELECTED FROM THE CLASS CONSISTING OF MONO- AND DI-HYDROXY ALKANES CONTAINING FROM 1 TO 3 CARBON ATOM S, CONTINUING SAID EXTRACTION UNTIL SUBSTANTIALLY PURE TERPHATALIC ACID REMAINS AS RESIDUE, SEPARATING AN EXTRACT RICH IN ISOPHATHALIC ACID FROM SAID TEREPHTHALIC ACID RESIDUE, AND RECOVERING ISOPHTHALIC ACID FROM SAID EXTRACT.
References Cited (Backward Citations)
GB623836A
Cited
US2531173A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1959-04-10 | 1959-10-10 | 1960-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1963-04-10 | 1963-10-10 | 1964-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1967-04-10 | 1967-10-10 | 1968-04-10 | $7700.00 | Window Closed / Lapsed |