Methanol → Quinacridone

Participants

Reaction Conditions

Reaction Steps

To 270 g of polyphosphoric acid (117% phosphoric acid) heated at 85° C. was added 0.54 g of N-[3-(N,N-dimethylaminopropyl)] copper phthalocyanine followed by 13.5 g of 2,9-dichloroquinacridone. The mixture was stirred at 113° C. for 30 minutes, after which 40.5 g of 2,5-di(4-methoxyanilino)terephthalic acid was added. The resultant mixture was heated at 113° C. for five hours. After the melt was cooled to 95° C., the acid strength was adjusted to 113% by the dropwise addition of phosphoric acid. The mixture was slowly poured into 470 g methanol. The slurry was heated at reflux for two hours, diluted with water, and stirred at 60° C. for thirty minutes. The slurry was further diluted with water, after which the solid component was collected by filtration and washed with water until acid free. The presscake was reslurried in water (320 g total water), the pH adjusted to 8.5 with dilute aqueous sodium hydroxide, and 320 g of methanol was added. The resultant slurry was heated at 120° C. for six hours in a closed system (e.g., a pressure reactor). After the slurry was cooled to 45°-50° C., 4.8 g of wood rosin (as the sodium salt) was added. After the mixture was stirred for 30 minutes, 10.0 g of CaCl2.2H2O (dissolved in water) was added, the slurry stirred for one hour, and the pH acidified (if necessary) with phosphoric acid. The solid component was collected by filtration and washed with water. The wet cake can be dried or used as is for specific applications. Here, the wet cake was oven dried at 60° C. to give approximately 48 g of quinacridone as a deep violet pigment.

Provenance & Evidence