Reaction #1153149
ord-608417d5dca445718e0f2204c749ad2d
Reaction equation
Reagents
Conditions
Procedure
A stirred vessel is charged with 450 parts of polyphosphoric acid containing 83.0% P2O5. Then 37.5 parts of 2,5-dianilinoterephthalic acid and 112.5 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 then metered over the course of 5 minutes into a second stirred vessel containing 1731.8 parts of 40% strength phosphoric acid and is hydrolyzed at 25° C. with stirring. During hydrolysis, the temperature rises to 110° C. Following the hydrolysis, the phosphoric acid strength is 55%. The mixture is cooled to 90° C., 823.4 parts of water at 25° C. are added and stirred at 90° C. for 1 hour. Thereafter, the mixed-crystal pigment is filtered off with suction, washed to neutrality with water and dried at 80° C.