Oxidation process for preparing quinacridone pigments
US6313300A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 14, 2000 |
| Grant date | Nov 6, 2001 |
| Priority date | — |
| Expiry date | Aug 14, 2020 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09B48/00
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A process for preparing an unsubstituted or substituted quinacridone of the formula ##STR1## or a solid solution of quinacridones of the formula (I), PA1 wherein X and Y are independently 1 or 2 substituents selected from hydrogen, fluorine, chlorine, C.sub.1 -C.sub.3 alkyl, C.sub.1 -C.sub.3 alkoxy and COOR wherein R is hydrogen or C.sub.1 -C.sub.10 alkyl in which a salt of a corresponding 6,13-dihydroquinacridone of formula II ##STR2## PA1 having the same substitutions as the desired quinacridone of formula I, or a mixture of corresponding 6,13-dihydroquinacridones of formula II, is oxidized with an oxygen containing gas in the presence of an aqueous base and a catalytically effective amount of an oxidation catalyst, characterized in that the oxidation is performed in the presence of an polyglycolic reaction medium of formula EQU R.sub.1 --O--[(CH.sub.2).sub.m --(CHR.sub.1 ').sub.n --O].sub.x --O--R.sub.1 " (III).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.