Nitric Acid → 1-Nitroanthraquinone

Participants

Reaction Conditions

Reaction Steps

A suspension of 250 g. of anthraquinone in 200 ml. of methylene chloride is treated under reflux conditions, over the course of about 3 hours, with a nitration acid of 68.4 ml. of 98% strength nitric acid and 85.2 ml. of 100% strength sulphuric acid. The mixture is stirred for a further 4 hours at this temperature and cooled to 20°C. After 700 ml. of methylene chloride have been added, 190 ml. of 98% strength nitric acid are allowed to run in at 20°C. After stirring for about 30 minutes longer, the upper, organic phase is withdrawn and clarified by passing it through a frit, and the filter residue is rinsed with a mixture of 95 ml. of methylene chloride and 5 ml. of 98% strength nitric acid. The clear filtrate is decomposed with 500 ml. of water and the mixture is stirred for a further hour at about 20°C. The lemon-yellow precipitate is then filtered off and is washed successively with 2 × 100 ml. of methylene chloride and 2 × 100 ml. of 1% strength aqueous di-sec.-butylnaphthalene-sulphonate solution and finally with water until neutral. After drying at about 100°C, the yield is 229 g. The product contains 89% of 1-nitroanthraquinone and inter alia contains 0.25% of anthraquinone, <0.25% of 2-nitroanthraquinone and 1.4% of 1,5-dinitroanthraquinone. To remove the remaining subsidiary components, the 1-nitroanthraquinone obtained is stirred with 1,850 ml. of 2.5% strength sodium sulphite solution for 4 hours under reflux conditions, then filtered off hot, washed and dried. 204 g. of 1-nitroanthraquinone are obtained, containing 95% of 1-nitroanthraquinone, 0.25% of anthraquinone, <0.25% of 2-nitroanthraquinone and 0.9% of 1,5-dinitroanthraquinone. A further fraction of 12 g. of 1-nitroanthraquinone and 2 g. of anthraquinone remains in the methylene chloride mother liquor and can, after evaporation of the solvent, be reintroduced into the next nitration batch.

Provenance & Evidence