abstract |
Process for the preparation of dihydroquinacridones, quinacridones and quinacridonequinones by cyclization of 2,5-dianilino-3,6-dihydroterephthalic acid derivatives or 2,5-dianilinoterephthalic acid derivatives in liquid or solid state or as a solution, in each case in finely divided form or in the gas phase, optionally in Presence of an oxidizing agent. |