Patent US4304724A successfully refreshed from Google Patents.
US4304724A
Expired / Lapsed
US
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Process for the manufacture of anthraquinone
Assignee: Dow Chemical Co
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Filing: 1980-12-22
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Granted: 1981-12-08
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Expires: 2000-12-22
Abstract
Abstract The present invention provides a process for making anthraquinone by the cyclization reaction of orthobenzoylbenzoic acid. The process uses as a catalyst a cation-exchange resin formed from a polymer with a polytetrafluoroethylene backbone and sulfonic-acid sidechains.
Inventors
- 👤 Michael O. Nutt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:43
CPC Classifications
C; C07; C07C; C07C46/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
32 words
A process for making of anthraquinone, comprising the step of contacting a solution of ortho-benzoylbenzoic acid in an inert solvent with a perfluorinated cation-exchange resin, in the acid form, at a temperature
Claim 2
Dependent Claim
32 words
A process for making of anthraquinone, comprising the step of contacting a solution of ortho-benzoylbenzoic acid in an inert solvent with a perfluorinated cation-exchange resin, in the acid form, at a temperature
Claim 3
Dependent Claim
14 words
The process of claim 1, wherein the resin is formed from a polymer with
Claim 4
Dependent Claim
14 words
The process of claim 2, wherein the resin is formed from a polymer with
Claim 5
Dependent Claim
10 words
The process of claim 3, wherein the solvent is ortho-dichlorobenzene.
Claim 6
Dependent Claim
11 words
The process of claim 4, wherein the temperature is between about
Claim 7
Dependent Claim
11 words
The process of claim 5, wherein the temperature is between about
Claim 8
Dependent Claim
17 words
The process of claim 6, wherein the temperature is between about 145° C. and about 155° C.
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) | 1984-12-07 | 1985-06-08 | 1985-12-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-12-07 | 1989-06-08 | 1989-12-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-12-07 | 1993-06-08 | 1993-12-08 | $7700.00 | Window Closed / Lapsed |