PURPOSE: To obtain in high yield the titled high-qualitay compound, by subjecting aminoanthraquinone in the presence of dimethylimidazolidinone to condensation reaction and treating wet filter cake with an aqueous solution of methanol.
CONSTITUTION: (A) 1-Aminoanthraquinone is subjected to condensation reaction in the presence of (B) 1,3-dimethyl-2-imidazolidinone at an elevated temperature by the use of (C) (i) an oxidizing agent such as air, oxygen, etc., and (ii) an alkali condensation agent such as potassium hydroxide, etc. The prepared reaction solution and wet filter cake containing the condensation reaction product are treated with ≥50wt% aqueous solution of methanol and 1,3-dimethyl-2- imidazolidinone in the treated solution is distilled and recovered, to give the aimed compound.
KATO KIMITOSHI
SAKAI TSUNEHIRO
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