Patent US3011955A successfully refreshed from Google Patents.
US3011955A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Purification of phthalic anhydride
Assignee: Scientific Design LLC
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Filing: 1959-06-04
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Granted: 1961-12-05
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Expires: 1979-06-04
Abstract
No abstract record available.
Inventors
- 👤 Brown David
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 18:30
CPC Classifications
C; C07; C07C; C07C51/00; C07C51/54; C07C51/573
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
49 words
IN COMBINATING WITH THE HEATING AND FRACTIONAL DISTILLATION OF A PHTALIC ANHYDRIDE CONTAINING MELT, THE IMPROVEMENT COMPRISING RAPIDLY FLASHING THE MELT TO SUBSTANTIALLY DISENGAGE PHTHALIC ANHYDRIDE FROM IMPURITIES IN THE MELT, SAID FLASHING BEING CONDUCTED FOLLOWING THE SAID HEATING OF SAID MELT AND PRIOR TO THE FRACTIONAL DISTILLATION THEREOF.
Claim 2
Dependent Claim
49 words
IN COMBINATING WITH THE HEATING AND FRACTIONAL DISTILLATION OF A PHTALIC ANHYDRIDE CONTAINING MELT, THE IMPROVEMENT COMPRISING RAPIDLY FLASHING THE MELT TO SUBSTANTIALLY DISENGAGE PHTHALIC ANHYDRIDE FROM IMPURITIES IN THE MELT, SAID FLASHING BEING CONDUCTED FOLLOWING THE SAID HEATING OF SAID MELT AND PRIOR TO THE FRACTIONAL DISTILLATION THEREOF.
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) | 1964-12-04 | 1965-06-05 | 1965-12-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1968-12-04 | 1969-06-05 | 1969-12-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1972-12-04 | 1973-06-05 | 1973-12-05 | $7700.00 | Window Closed / Lapsed |