초록 ▼

Linear unsubstituted and substituted quinacridone pigments and quinacridone mixed-crystal pigments are obtained by cyclizing dianilinoterephthalic acid with polyphosphoric acid and then hydrolyzing the ring closure mixture, said mixture being metered into an amount of water or orthophosphoric acid w

Linear unsubstituted and substituted quinacridone pigments and quinacridone mixed-crystal pigments are obtained by cyclizing dianilinoterephthalic acid with polyphosphoric acid and then hydrolyzing the ring closure mixture, said mixture being metered into an amount of water or orthophosphoric acid which is such that the final orthophosphoric acid concentration is greater than or equal to 50% by weight in the hedrolysis mixture.

대표청구항 ▼

[ What is claimed is:] [1.]1. A process for preparing pigments, mixed-crystal pigments and pigment preparations on the basis of linear unsubstituted or substituted quinacridones of the formula (I) which the substituents R.sup.1 and R.sup.2 are identical or different and are hydrogen, chlorine, bromi

[ What is claimed is:] [1.]1. A process for preparing pigments, mixed-crystal pigments and pigment preparations on the basis of linear unsubstituted or substituted quinacridones of the formula (I) which the substituents R.sup.1 and R.sup.2 are identical or different and are hydrogen, chlorine, bromine or fluorine atoms or C.sub.1 -C.sub.4 -alkyl, C.sub.1 -C.sub.4 -alkoxy or carboxamido groups, which are optionally substituted by C.sub.1 -C.sub.6 -alkyl groups; or are phenoxy rings or C.sub.6 -C.sub.10 -aryl rings onto which further aromatic, aliphatic or heterocyclic rings are optionally fused, by cyclizing dianilinoterephthalic acid of the formula (Ia) h polyphosphoric acid or polyphosphoric ester to give a ring closure mixture and subsequently hydrolyzing said ring closure mixture comprising quinacridone and polyphosphoric acid or polyphosphoric ester, which comprises metering the ring closure mixture comprising quinacridone and polyphosphoric acid or polyphosphoric ester into an amount of water or aqueous orthophosphoric acid to produce a hydrolysis mixture having a final orthophosphoric acid concentration greater than or equal to 50% by weight.