US3818052A
Expired / Lapsed
US
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Process for isolating 1,5-and 1,8-dinitro-anthraquinone from anthraquinone nitration mixtures
Assignee: Bayer AG
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Filing: 1972-08-28
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Granted: 1974-06-18
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Expires: 1992-08-28
Abstract
Abstract Process for the manufacture of 1,5-dinitro-anthraquinone and 1,8-dinitro-anthraquinone of a high degree of purity, characterized by nitration of anthraquinone in sulphuric acid and isolation of 1,5-dinitro-anthraquinone from the reaction mixture by adjusting to an SO3-content of 8 - 20 percent and subsequently isolating 1,8-dinitroanthraquinone from the mother liquor by adjusting to a sulphuric acid content of 80 - 100 percent.
Inventors
- 👤 W Hohmann
- 👤 H Scheiter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 17:40
CPC Classifications
C; C07; C07C; C07C225/00; C07C225/24; C07C225/26; C07C225/32; C07C225/34
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
56 words
Process for the manufacture of 1,5-dinitro-anthraquinone of a degree of purity of least 80 percent, which contains 1,8-dinitro-anthraquinone as the significant impurity and which is practically free of 1,6- and 1,7-dinitro-anthraquinone, characterized in that a sulphuric acid-anthraquinone nitration mixture is adjusted to an SO3 content of 8-20 percent and the undissolved 1,5-dinitro-anthraquinone is subsequently separated off.
Claim 2
Dependent Claim
58 words
Process for the manufacture of 1,8-dinitro-anthraquinone by nitration of an anthraquinone in sulphuric acid, characterized in that the nitration mixture is adjusted to an SO3 content of 10-17 percent, the insoluble 1,5-dinitro-anthraquinone is separated off, the mother liquor is diluted to a sulphuric acid content of about 92-100 percent, and the 1,8-dinitro-anthraquinone which thereupon precipitates is separated off.
Claim 3
Dependent Claim
62 words
Process for separating a mixture, consisting essentially of 1,5-dinitro-anthraquinone and 1,8-dinitro-anthraquinone, into 1, 5-dinitro-anthraquinone and 1,8-dinitro-anthraquinone, characterized in that the mixture is treated with sulphuric acid having an SO3 content of 10-17 percent, the insoluble 1,5-dinitro-anthraquinone is separated off, the mother liquor is diluted to a sulphuric acid content of about 80-100 percent, and the 1,8-dinitro-anthraquinone which thereupon precipitates is separated off.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-17 | 1977-12-17 | 1978-06-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-17 | 1981-12-17 | 1982-06-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-17 | 1985-12-17 | 1986-06-18 | $7700.00 | Window Closed / Lapsed |