Methanol → Quino[2,3-b]acridine-7,14-dione, 2,9-dichloro-5,12-dihydro-

Participants

Reaction Conditions

Reaction Steps

To 720 g of polyphosphoric acid (116.5%) heated at 89° C. were added 120 g of 2,5-di(4-chloroanilino)terephthalic acid over a period of approximately 45 minutes, the temperature being maintained below 110° C. by adjustment of the addition rate. The reaction mixture was held at 113° C. for five hours and then cooled to 95° C. To this mixture was added 89.4 g of phosphoric acid (75%) dropwise over a period of 20 minutes. The resultant melt was allowed to stir for 15 minutes at 92° C. and then poured slowly into 1240 g of methanol, the temperature being maintained below reflux by adjustment of the addition rate. The slurry was allowed to cool to room temperature and stand for 16 hours. The pigment slurry was heated at reflux for one hour, cooled below 65° C., diluted with water, collected by filtration, and washed with water until free of acid. The resultant wet cake can be dried or used as is for specific applications. Here, the wet cake was dried in an oven at 60° C. to give approximately 102 g of 2,9-dichloroquinacridone as a magenta pigment.

Provenance & Evidence