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US2848488A
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Crystallization of phthalic acids
Assignee: Richfield Oil Corp
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Filing: 1954-05-18
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Granted: 1958-08-19
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Expires: 1974-05-18
Abstract
No abstract record available.
Inventors
- 👤 Chester M Himel
- 👤 Lester P Berriman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 11:50
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/42; C07C51/43; B; B01; B01D; B01D9/00; B01D9/0004; C07C51/16; C07C51/27; C07C51/275
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
130 words
THE MIXTURE OF CRYSTALLIZING IN THE LIQUID PHASE A MIXTURE COMPRISING TEREPHTHALIC ACID AND ISOPHTHALIC ACID, WHICH MIXTURE IS OBTAINED AS A CONTINUOUS EFFLUENT FROM A LIQUID PHASE NITRIC ACID OXIDATION REACTION CON DUCTED AT AN ELEVATED PRESSURE AND A TEMPERATURE FROM ABOUT 160 TO 250*C., WHICH COMPRISES CONTINUOUSLY REMOVING THE EFFLUENT CONTAINING THE PHTHALIC ACIDS FROM THE OXIDATION REACTION, COOLING THE EFFLUENT THROUGH RELEASE OF PRESSURE AT A RATE TO MAINTAIN THE EFFLUENT TEMPERATURE WITHIN THE RANGE FROM ABOUT 190 TO 160*C. FOR AT LEAST TWO MINUTES TO EFFECT CRYSTALLIZATION OF TEREPHTHALIC ACID, AND THEN COOLING THE EFFLUENT THROUGH RELEASE OF PRESSURE AT A RATE TO MAINTAIN THE EFFLUENT TEMPERATURE WITHIN THE RANGE FROM ABOUT 150 TO 115*C. FOR AT LEAST FIVE MINUTES TO EFFECT CRYSTALLIZATION OF ISOPHTHALIC ACID.
Claim 2
Dependent Claim
130 words
THE MIXTURE OF CRYSTALLIZING IN THE LIQUID PHASE A MIXTURE COMPRISING TEREPHTHALIC ACID AND ISOPHTHALIC ACID, WHICH MIXTURE IS OBTAINED AS A CONTINUOUS EFFLUENT FROM A LIQUID PHASE NITRIC ACID OXIDATION REACTION CON DUCTED AT AN ELEVATED PRESSURE AND A TEMPERATURE FROM ABOUT 160 TO 250*C., WHICH COMPRISES CONTINUOUSLY REMOVING THE EFFLUENT CONTAINING THE PHTHALIC ACIDS FROM THE OXIDATION REACTION, COOLING THE EFFLUENT THROUGH RELEASE OF PRESSURE AT A RATE TO MAINTAIN THE EFFLUENT TEMPERATURE WITHIN THE RANGE FROM ABOUT 190 TO 160*C. FOR AT LEAST TWO MINUTES TO EFFECT CRYSTALLIZATION OF TEREPHTHALIC ACID, AND THEN COOLING THE EFFLUENT THROUGH RELEASE OF PRESSURE AT A RATE TO MAINTAIN THE EFFLUENT TEMPERATURE WITHIN THE RANGE FROM ABOUT 150 TO 115*C. FOR AT LEAST FIVE MINUTES TO EFFECT CRYSTALLIZATION OF ISOPHTHALIC ACID.
References Cited (Backward Citations)
US2734914A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1961-08-18 | 1962-02-17 | 1962-08-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1965-08-18 | 1966-02-17 | 1966-08-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1969-08-18 | 1970-02-17 | 1970-08-19 | $7700.00 | Window Closed / Lapsed |