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

Participants

Reaction Conditions

Reaction Steps

To 900 g of polyphosphoric acid (116.5%) heated at 90° C. were added 3.0 g of 2,5-di(sulfamoylanilino)terephthalic acid followed by 7.5 g of 2,5-di[4-(N,N-diethylsulfamoyl)anilino]terephthalic acid. The mixture was stirred for five minutes, after which 150 g of 2,5-di(4-chloroanilino)terephthalic acid were added over a period of approximately 45 minutes, the temperature being maintained below 115° C. by adjustment of the addition rate. The reaction mixture was held at 113° C. for four hours and then cooled to 94° C. To this mixture was added 110.2 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 1550 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 140 g of 2,9-dichloroquinacridone as a magenta pigment. A portion of the pigment was used to prepare a blend containing 90% by weight of the pigment and 10% by weight of phthalimidomethylquinacridone.

Provenance & Evidence