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AssigneeSumitomo Chemical Company, Limited
InventorsEiji Yamada, Akira Fukasawa, Shinzaburo Masaki
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A process for producing 1-nitroanthraquinone with high purity which comprises treating crude 1-nitroanthraquinone containing as the main impurities dinitroanthraquinones and .beta.-nitroanthraquinone with an alkali sulfite in an aqueous medium under heating and which is characterized in that the crystals of the crude 1-nitroanthraquinone are pulverized by the aid of a pulverizer, a fine pulverizer or an ultra-fine pulverizer prior to and/or during the treatment with the aqueous alkali sulfite; and a process for producing 1-aminoanthraquinone which comprises subjecting the reaction mixture obtained by the said treatment with the alkali sulfite solution mentioned above, if necessary after further fine pulverization, to a reaction with a reducing agent, or ammonia or an aliphatic or aromatic amine.
In a process for producing 1-nitroanthraquinone with high purity by treating crude 1-nitroanthraquinone containing as the main impurities dinitroanthraquinones and .beta.-nitroanthraquinones with an aqueous alkali sulfite or bisulfite solution under heating, the improvement which comprises pulverizing the crude 1-nitroanthraquinone prior to and/or during the treatment with the aqueous alkali sulfite or bisulfite solution.
In a process for producing 1-aminoanthraquinone by treating crude 1-nitroanthraquinone containing as the main impurities dinitroanthraquinones and .beta.-nitroanthraquinone with an aqueous alkali sulfite or bisulfite solution and then reacting the resulting mixture or the purified 1-nitroanthraquinone isolated from the resulting mixture with a reducing agent, or ammonia or an aliphatic or aromatic amine, the improvement which comprises pulverizing the crude 1-nitroanthraquinone prior to and/or during the treatment with the aqueous alkali sulfite or bisulfite solution.
Dependencies are inferred from the claim text.