Process for the preparation of 1-amino-2-bromo-4-hydroxyanthraquinone
US4648994A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 24, 1986 |
| Grant date | Mar 10, 1987 |
| Priority date | — |
| Expiry date | Jan 24, 2006 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09B1/503
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
The invention discloses a process for the preparation of 1-amino-2-bromo-4-hydroxyanthraquinone by brominating 1-aminoanthraquinone in the 2- and 4-position in concentrated sulfuric acid and subsequently hydrolyzing the 1-amino-2,4-dibromoanthraquinone obtained as intermediate, which process comprises removing excess bromine and/or hydrobromic acid formed during the bromination from the reaction mixture and carrying out the hydrolysis at elevated temperature in the presence of an aldehyde. 1-Amino-2-bromo-4-hydroxyanthraquinone is an important intermediate for dyestuff synthesis and is used in particular for synthesizing anthraquinoid disperse dyes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.