Hydrogen Peroxide → Quinacridone

Participants

Reaction Conditions

Reaction Steps

A one liter flask equipped with a thermometer, stirrer and condenser was charged with 50 grams 6,13-dihydroquinacridone, 310 ml methanol and 66 grams 50% aqueous sodium hydroxide and 3.8 grams 50% aqueous benzyl tributyl ammonium chloride solution and stirred for 5 minutes at 35-40° C. 0.9 grams anthraquinone sulfonic acid methyl quinacridone pigment additive prepared according to Example 4 was added followed by the addition of 0.5 grams anthraquinone mono sulfonic acid sodium salt as catalyst. The mixture was stirred under a slow flow of nitrogen and heated to reflux. 91.4 grams of an aqueous 17% hydrogen peroxide solution were added into the reaction mixture with a peristaltic pump at a pumping rate of 0.3 minute. The resulting red 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 48.9 grams red quinacridone.

Provenance & Evidence