Sulfuric Acid → Quinacridone

Participants

Reaction Steps

A stainless steel flask having a refluxing device was charged with 10 parts of the 6,13-dihydroquinacridone obtained in Example 1 and 80 parts of methanol, and the mixture was stirred. 12 Parts of a 50% NaOH aqueous solution was added, and the mixture was stirred at 40° C. for 30 minutes to form a salt. 26 Parts of 10% sulfuric acid was added to hydrolyze the salt, and the resultant solution was refluxed for 1 hour. Then, 10 parts of sodium m-nitrobenzenesulfonate was added, and immediately thereafter, 3 parts of a 50% NaOH aqueous solution was added. Then, the mixture was refluxed for 4 hours to give 9.8 parts (98.8% of a theoretical value) of a nonsubstituted quinacridone as a pigment having a uniform particle diameter. The so-obtained quinacridone had a specific surface area of 25.1 m2 /g.

Provenance & Evidence