Patent US2820819A successfully refreshed from Google Patents.
US2820819A
Expired / Lapsed
US
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Separation of isomeric phthalic acids
Assignee: California Research LLC
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Filing: 1952-12-30
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Granted: 1958-01-21
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Expires: 1972-12-30
Abstract
No abstract record available.
Inventors
- 👤 Harry J Aroyan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 16:48
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/42
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
79 words
A PROCESS FOR SEPARATING A MIXTURE OF ISOPHTHALIC ACID AND TEREPHTHALIC ACID CONTAINING FROM 2 TO 95% BY WEIGHT OF TEREPHTHALIC ACID, WHICH COMPRISES INTIMATELY CONTACTING THE MIXTURE WITH WATER AT AN ELEVATED TEMPERATURE IN THE RANGE 350* TO 500*F., UNDER AN ELEVATED PRESSURE SUFFICIENT TO MAINTAIN THE WATER IN LIQUID PHASE, AT SAID ELEVATED TEMPERATURE TO FORM A SLURRY, AND SEPARATING A SOLID PHASE AND A LIQUID PHASE FROM THE SLURRY WHILE MAINTAINING SAID ELEVATED TEMPERATURE AND PRESSURE.
Claim 2
Dependent Claim
79 words
A PROCESS FOR SEPARATING A MIXTURE OF ISOPHTHALIC ACID AND TEREPHTHALIC ACID CONTAINING FROM 2 TO 95% BY WEIGHT OF TEREPHTHALIC ACID, WHICH COMPRISES INTIMATELY CONTACTING THE MIXTURE WITH WATER AT AN ELEVATED TEMPERATURE IN THE RANGE 350* TO 500*F., UNDER AN ELEVATED PRESSURE SUFFICIENT TO MAINTAIN THE WATER IN LIQUID PHASE, AT SAID ELEVATED TEMPERATURE TO FORM A SLURRY, AND SEPARATING A SOLID PHASE AND A LIQUID PHASE FROM THE SLURRY WHILE MAINTAINING SAID ELEVATED TEMPERATURE AND PRESSURE.
References Cited (Backward Citations)
US2572575A
Cited
US2697723A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-01-20 | 1961-07-22 | 1962-01-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-01-20 | 1965-07-22 | 1966-01-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-01-20 | 1969-07-22 | 1970-01-21 | $7700.00 | Window Closed / Lapsed |