US3972902A
Expired / Lapsed
US
⏱️ 0.0 years remaining
4,4'-Isopropylidene-bis(3- and 4-phenyleneoxyphthalic anhydride)
Assignee: General Electric Co
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Filing: 1972-08-18
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Granted: 1976-08-03
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Expires: 1992-08-18
Abstract
Abstract Aryloxy dianhydrides are prepared from the hydrolysis of the reaction product of a nitro-substituted phenyl dinitrile with a metal salt of a dihydroxy aryl compound in the presence of a dipolar aprotic solvent.
Inventors
- 👤 Darrell R. Heath
- 👤 Joseph G. Wirth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 17:36
CPC Classifications
C; C08; C08G; C08G73/00; C08G73/06; C08G73/10; C08G73/1067; C08G73/1071; C07; C07C; C07C65/00; C07C65/21; C07C65/24; C07D; C07D307/00; C07D307/77; C07D307/87; C07D307/89; C08G59/00; C08G59/18; C08G59/40; C08G59/42; C08G59/4223; C08G59/423; C08G73/1003; C08G73/1035; C08G73/1046; C08G73/1053; C08G73/1057; C08G73/1064
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
4 words
The compound 2,2-bis-[4-(2,3-dicarboxyphenoxy)phenyl]propane dianhydride.
Claim 2
Dependent Claim
4 words
The compound 2,2-bis-[4-(2,3-dicarboxyphenoxy)phenyl]propane dianhydride.
Claim 3
Dependent Claim
4 words
The compound 2,2-bis-[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride.
Claim 4
Dependent Claim
4 words
The compound 2,2-bis-[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride.
References Cited (Backward Citations)
FR2030905A5
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-03 | 1980-02-02 | 1980-08-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-03 | 1984-02-02 | 1984-08-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-03 | 1988-02-02 | 1988-08-03 | $7700.00 | Window Closed / Lapsed |