Process for production of 1-aminoanthraquinone

A process for producing 1-aminoanthraquinone, which comprises

• (a) oxidizing 1-nitronaphthalene in the liquid phase with an acidic aqueous solution consisting essentially of nitric acid or acetic acid containing a ceric ion reducible to a cerous ion as an oxidizing agent and separating crystals containing 5-nitro-1,4-naphthoquinone and said acidic aqueous solution containing a cerium ion from the resulting reaction mixture,
• (b) subjecting said 5-nitro-1,4-nathphoquinone obtained in step (a) to Diels-Alder reaction with 1,3-butadiene in a solvent, precipitating crystals containing the resulting 5-nitro-1,4 4a, 9a-tetrahydroanthraquinone, separating said crystals by filtration, separating and recovering the unreacted 1-nitronaphthalene and the solvent in the filtrate in a separation tower, and recycling said 1-nitronaphthalene to step (a) for use as the starting material and re-using said recovered solvent for the Diels-Alder reaction,
• (c) reducing said 5-nitro-1,4,4a,9a-tetrahydroanthraquinone obtained in step (b) to form 1-aminoanthraquinone, separating crystals containing 1-aminoanthraquinone and purifying said crystals, and
• (d) electrolytically oxidizing said acidic aqueous solution containing cerium ion separated in step (a) to convert the cerous ion in said acidic aqueous solution to a ceric ion and recycling the resulting acidic aqueous solution containing a ceric ion to step (a) for re-use as the oxidizing agent.