Patent ID: 6313300
Filing Date: 2001-11-06
Classification: C07D,C09B

Abstract:
A process for preparing an unsubstitued or substituted quinacridone of formula ##STR5##or a solid solution of quinacridones of formula (I), wherein X and Y in formula (I) 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, said process comprising:a) oxidizing a salt of a corresponding 6,13-dihydroquinacridones of formula ##STR6##or salts of corresponding 6,13-dihydroquinacridones of formula II, with air or an oxygen containing gas mixture in a homogenous liquid reaction medium that consists essentially of an oxidative effective amount of a compound represented by formulaR.sub.1 --O--[(CH.sub.2).sub.m --(CHR.sub.1 ').sub.n --O].sub.x --O--R.sub.1 "" (III),wherein R.sub.1, R.sub.1 ', R.sub.1 "" are, independently of one another, hydrogen or C.sub.1 -C.sub.4 alkyl, or R.sub.1 and R.sub.1 "" are together C.sub.2 -C.sub.4 alkylene, m and n are 1 to 4, and x is 3 to 1000, in the presence of an aqueous base and a catalyst, wherein the compound according to formula (III) is present in an amount of at least 2 parts by weight per part by weight of the dihydroquinacridone or salt thereof to form an unsubstituted or substituted quinacridone that is dissolved in said reaction medium;b) precipitation said dissolved unsubstituted or substituted quinacridone or the mixture of quinacridones from the reaction mixture of step a; andc) recovering said unsubstituted or substituted quinacridone or a solid solution of two or more quinacridones.