US3884924A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the preparation of acenaphthene-5,6-dicarboxylic acid imide
Assignee: Hoechst AG
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Filing: 1974-01-30
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Granted: 1975-05-20
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Expires: 1994-01-30
Abstract
Abstract A process for the preparation of acenaphthene-5,6-dicarboxylic acid imide of the formula (1) WHICH COMPRISES REACTING ACENAPHTHENE OF THE FORMULA (2) WITH AN ALKALI METAL CYANATE IN AN AT LEAST 90% HYDROFLUORIC ACID AT A TEMPERATURE OF FROM -10*C to 120*C, which represents a technically advantageous process because it allows the hydrofluoric acid used in excess to be recovered in contradistinction to known processes.
Inventors
- 👤 Kurt Eiglmeier
- 👤 Henning Lubbers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 05:13
CPC Classifications
C; C07; C07D; C07D221/00; C07D221/02; C07D221/04; C07D221/18
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
13 words
A PROCESS FOR THE PREPARATION OF ACENAPHTHENE-5,6DICARBOXYLIC ACID IMIDE OF THE FORMULA (1)
Claim 2
Dependent Claim
13 words
A PROCESS FOR THE PREPARATION OF ACENAPHTHENE-5,6DICARBOXYLIC ACID IMIDE OF THE FORMULA (1)
Claim 3
Dependent Claim
29 words
A process as claimed in claim 1, wherein the starting compounds are introduced into hydrofluoric acid prior to the reaction at a temperature of from about -10* to -30*C.
References Cited (Backward Citations)
US3455922A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-05-19 | 1978-11-18 | 1979-05-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-05-19 | 1982-11-18 | 1983-05-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-05-19 | 1986-11-18 | 1987-05-20 | $7700.00 | Window Closed / Lapsed |