Patent US2537873A successfully refreshed from Google Patents.
US2537873A
Expired / Lapsed
US
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Process of manufacturing 4, 5-diphenyl phthalic anhydrides
Assignee: Eastman Kodak Co
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Filing: 1948-03-10
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Granted: 1951-01-09
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Expires: 1968-03-10
Abstract
No abstract record available.
Inventors
- 👤 Charles F H Allen
- 👤 James A Van Allan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 21:24
CPC Classifications
C; C07; C07C; C07C63/00; C07C63/33; C07C63/331
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
40 words
A PROCESS OF MANUFACTURING A 4,5-DIPHENYL PHTHALIC ANHYDRIDE, WHICH COMPRISES HEATING AN ANHYDROACETONE BENZIL SELECTED FROM THE GROUP CONSISTING OF ANHYDROACETONE BENZIL AND THE LOWER A-ALKYL ANHYDROACETONE BENZILS WITH CHLOROMALEIC ANHYDRIDE AND A CATALYTIC AMOUNT OF A DEHYDRATING MINERAL ACID.
Claim 2
Dependent Claim
40 words
A PROCESS OF MANUFACTURING A 4,5-DIPHENYL PHTHALIC ANHYDRIDE, WHICH COMPRISES HEATING AN ANHYDROACETONE BENZIL SELECTED FROM THE GROUP CONSISTING OF ANHYDROACETONE BENZIL AND THE LOWER A-ALKYL ANHYDROACETONE BENZILS WITH CHLOROMALEIC ANHYDRIDE AND A CATALYTIC AMOUNT OF A DEHYDRATING MINERAL ACID.
References Cited (Backward Citations)
US2097854A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1954-01-08 | 1954-07-10 | 1955-01-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1958-01-08 | 1958-07-10 | 1959-01-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1962-01-08 | 1962-07-10 | 1963-01-09 | $7700.00 | Window Closed / Lapsed |