Hydrogen Peroxide → Quinacridone

Participants

Reaction Conditions

Reaction Steps

A one liter flask equipped with a thermometer, stirrer and condenser was charged with 40 grams 6,13dihydroquinacridone, 250 ml methanol, 52.8 grams 50% aqueous sodium hydroxide and 3.0 grams 50% aqueous benzyl tributyl ammonium chloride. The mixture was stirred under a slow flow of nitrogen at 30 to 45° C. for five minutes, heated to 50 to 55° C. and stirred at 50 to 55° C. for one hour. 0.6 grams of pigment additive melamine methyl dihydroquinacridone prepared according to Example 4 was added, followed by the addition of 0.5 grams anthraquinone mono sulfonic acid sodium salt, as catalyst, and the reaction mixture was heated to reflux. 73 grams of an aqueous 17% hydrogen peroxide solution were added into the reaction mixture with a peristaltic pump at a setting of 0.3 ml/minute maintaining reflux under a slow nitrogen flow. The resulting reddish suspension was further stirred for 10 minutes at reflux then diluted with 100 ml cold water and filtered. The presscake was washed with hot water then dried, yielding 38.9 grams red quinacridone.

Provenance & Evidence