Hydrogen Peroxide → Quinacridone

Participants

Reaction Conditions

Reaction Steps

A one liter flask equipped with a thermometer, stirrer and condenser was charged with 40 grams 6,13-dihydroquinacridone, 180 ml methanol, 42.5 grams 50% aqueous sodium hydroxide and 14.6 grams of an aqueous presscake containing 1.6 grams naphthalin-1-sulfonic acid methyl quinacridone pigment additive prepared according to Example 2 of Copending U.S. Provisional Patent Application entitled “PIGMENT PARTICLE GROWTH AND/OR CRYSTAL PHASE DIRECTORS”. The mixture was stirred under a slow flow of nitrogen at 50 to 55° C. for one hour. 0.5 grams anthraquinone mono sulfonic acid sodium salt, as catalyst, were added and the reaction mixture was heated to reflux. 67 grams of an aqueous 19.3% hydrogen peroxide solution were added into the reaction mixture with a peristaltic pump at a pumping rate of 0.3 ml/minute, whereby after 15 minutes addition time, 1.2 grams phthalimidomethyl dihydroquinacridone obtained according to Example 2 were added into the reaction mixture followed by another addition of 0.8 grams phthalimidomethyl dihydroquinacridone after 45 minutes while continuously adding the hydrogen peroxide by maintaining reflux and a slow nitrogen flow. The resulting violet 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 violet quinacridone.

Provenance & Evidence