2,5-Dianilinoterephthalic acid → Quinacridone

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

450 parts of polyphosphoric acid containing 85.0% P2O5 are metered into a stirred vessel. Then 135 parts of 2,5-dianilinoterephthalic acid, 11.25 parts of 2,5-di(3-chloroanilino) terephthalic acid and 3.75 parts of 2,5-di(4-toluidino)terephthalic acid are introduced at 125° C. with stirring and the mixture is heated at 125° C. for 1 hour during which ring closure takes place to form the quinacridone. The reaction mixture is subsequently metered with stirring over 2 minutes (CG: 50%/min) into 1607.5 parts of 80% strength phosphoric acid at 135° C., during which it is hydrolyzed. During this hydrolysis the temperature rises to 150° C. The phosphoric acid concentration after the hydrolysis is 87.5%. Then 1209.2 parts of 40% strength phosphoric acid are added dropwise and the suspension is cooled to 120° C. The phosphoric acid concentration thereafter is 70%. The mixture is stirred at 120° C. for 1 hour. Subsequently the mixed crystal pigment is filtered off with suction at 110° C., washed with 70% strength phosphoric acid until the runoff is colorless, washed to neutrality with water, and dried at 80° C. This gives 131.9 parts of mixed crystal pigment (Pigment Violet 19, γIV phase). In the AM lacquer, transparent and strongly colored coatings of deep hue are obtained. The rheology is evaluated as 3 and the viscosity is 4.2 s. The gloss measurement gives a value of 58.

Herkunft & Nachweise