Methanol → Quinacridone

Participants

Reaction Conditions

Reaction Steps

To 130 parts of 118 percent polyphosphoric acid (118 percent H3PO4) are added 18 parts of 2,5-dianilinoterephthalic acid and the mixture is heated at 102° to 106° C. for 16 hours. The resulting thick solution is cooled to 90° C. and poured into 250 parts of methanol over a period of 5 minutes at a rate such that the temperature of the methanol is not allowed to exceed 15° C. The methanol is maintained at between 0° and 15° C. by means of an ice bath. After addition is complete, the mixture is stirred for 15 minutes at 15° C. or below and then heated to reflux for 11/2 hours. After allowing the mixture to cool to about 90° C it is drowned into 400 parts of water at 20° C., heated at 60° C. and boiled for 1/2 hour. The solid is filtered, washed acid free, reslurried with 1000 parts of water and boiled with 50 parts of 50 percent NaOH for 1 hour. The solid is again filtered, washed acid free and dried at 180° F. to yield 15 parts of pure pigmentary gamma quinacridone.

Provenance & Evidence