- An efficient procedure for the preparation of 1-nitroanthraquinone
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A novel and efficient method is developed for the selective mono nitration of anthraquinone (1). A mixture of fuming nitric acid, sulfuric acid and phosphoric acid in carbon tetrachloride is introduced as a new nitrating system for the high yield preparation of 1-nitroanthraquinone.
- Sharghi,Tamaddon
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- Separation of 1,5-dinitroanthraquinone and 1,8-dinitroanthraquinone
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A process for separating 1,5-dinitroanthraquinone and 1,8-dinitroanthraquinone by heating a dinitroanthraquinone mixture, in a mixture of from 5 to 85 per cent by weight of N-methylpyrrolidone and from 95 to 15 per cent by weight of an organic liquid which boils at from 80° to 210° C and is miscible in all proportions with N-methylpyrrolidone, at from 60° to 180° C, and separating off the undissolved material, at the extraction temperature, after the solution equilibrium has been reached. The insoluble material contains more than 85 per cent by weight, and as a rule more than 90 per cent by weight, of 1,5-dinitroanthraquinone. From the extract, it is possible to isolate the dissolved 1,8-dinitroanthraquinone together with the dissolved 1,5-dinitroanthraquinone and any byproducts which may be present.
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- Process for producing 1,5-dinitroanthraquinone and 1,8-dinitroanthraquinone
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Substantially pure 1,5- and/or 1,8-dinitroanthraquinone is recovered from dinitration mixtures which may contain sulfuric acid or a perfluoralkane sulfonic acid by adjusting the nitric acid concentration in the nitration mixture to a value of 91 to 96% for a ratio by weight of nitric acid to solids of from 2.5 : 1 to 10 : 1; separating off the insoluble crude 1,5-dinitroanthranthraquinone at 15° to 50°C; taking up the 1,5-dinitroanthraquinone with 90 to 100% nitric acid in a ratio by weight of nitric acid to solids of from 0.5 : 1 to 3.5 : 1; stirring at 15° to 80° C; separating off the insoluble pure 1,5-dinitroanthraquinone thus obtained; adjusting the mother liquid left following separation of the crude 1,5-dinitroanthraquinone to a nitric acid concentration of from 88 to 94% for a ratio by weight of nitric acid to solids of from 3.0 : 1 to 12 : 1, with the proviso that the nitric acid concentration is at least 1.5% lower than in the preceding separation of crude 1,5-dinitroanthraquinone; and separating off the pure 1,8-dinitroanthraquinone obtained in this way at a temperature in the range of from 20° to 50°C and freeing it from the nitric acid adhering thereto.
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- Process for the production of dinitro-anthraquinones
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Dinitro-anthraquinones are produced by nitrating an anthraquinone in the presence of an indifferent organic solvent. As inert organic solvents there is suggested an aliphatic or alicyclic hydrocarbon having up to 12 carbon atoms and substituted once or several times by halogen or by the nitro group.
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- Preparation of pure 1,5-dinitroanthraquinone
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A mixture of dinitroanthraquinones of which at least 35% is 1,5-dinitroanthraquinone is dissolved at elevated temperature in a halogenated aromatic hydrocarbon, a carboxylic acid nitrile or a cyclic sulphone and is thereafter cooled selectively to precipitate substantially pure 1,5-dinitroanthraquinone. Preferred solvents are 1-chloronaphthalene, sulpholane and adipic acid dinitrile. The temperature of dissolution ranges from about 120° C up to the boiling point and cooling is by about 10° to 200° C to a temperature not below about 0° C.
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- Preparation of pure 1,8-dinitroanthraquinone
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A mixture of dinitroanthraquinones of which at least 70% is 1,8-dinitroanthraquinone is dissolved at elevated temperature in a halogenated aromatic hydrocarbon, a carboxylic acid nitrile or a cyclic sulphone and is thereafter cooled selectively to precipitate substantially pure 1,8-dinitroanthraquinone. Preferred solvents are 1-chloronaphthalene, sulpholane and adipic acid dinitrile. The particular temperature of dissolution and cooling will depend upon the particular solvent.
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