Process for the production of quinizarine derivatives which are disubstituted in the 5- and 8-positions by hydroxyl or chlorine
US4645626A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 14, 1985 |
| Grant date | Feb 24, 1987 |
| Priority date | — |
| Expiry date | Aug 14, 2005 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C46/00
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The invention relates to a process for the production of 1,4,5,8-tetrahydroxyanthraquinone or 5,8-dichloro-1,4-dihydroxyanthraquinone by reacting phthalic anhydride with p-chlorophenol in oleum and in the presence of a boron catalyst, to give the quinizarine boron complex, and chlorinating this boron complex direct with a chlorinating agent, in the same reaction medium, to give the boron complex of dichloroquinizarine, and subsequently hydrolyzing this chlorinated boron complex to 1,4,5,8-tetrahydroxyanthraquinone or 5,8-dichloro-1,4-dihydroxyanthraquinone. The novel process is environmentally and economically more advantageous than the sum of each of the individual process steps.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.