Abstract: Process for working up aqueous nitric acid which is of a concentration above the azeotropic concentration and contains organic compounds in solution for suspension wherein said nitric acid of a concentration about the azeotropic concentration is distilled off in one or more rectification steps until the azeotropic nitric acid is obtained. In the process, certain specified ratios of nitric acid and water to organic constituents must be maintained.

Abstract: A process has been developed for isolating aromatic dinitro compounds by using nitric acid in specified concentrations in different portions of a rectifying column and separating off the mixture of aromatic dinitro compounds from the sump of the rectifying column.

Abstract: Process for the preparation of 1-alkylamino-anthraquinones which comprises reacting 1-nitroanthraquinone with a monoalkylamine in the presence of an ether, a hydrocarbon or a mixture of an ether and a hydrocarbon. The 1-alkylamino-anthraquinones which are obtained can be employed directly as dyestuffs or used, without further purification, for the production of dyestuffs. Process of the invention results in the procurement of 1-alkylamine-anthraquinones of high purity and in high yield and avoids the formation of undesired by-products.

Abstract: The purification of high-melting organic products, such an anthraquinone and substituted anthraquinones, which is substantially free from lower-boiling impurities, by melting the product to be purified by heating, while mechanically conveying the same along a path with a screw conveyer, as for example, in a melting screw; degassing the melt at a reduced pressure in a column, as for example, at a pressure of 50 to 400 mm Hg; passing the degassed melt through a thin film evaporator at a reduced pressure of, for example, 5 to 250 mm Hg to evaporate the high-melting organic product and discharging the remaining high-boiling impurities and such impurities which are not capable of being distilled from the evaporator through a conically tapering sump, while mechanically scraping residue from the sump wall, preferably with the use of a rotating helical screw in the sump; the discharge from the sump being effected into and through an enclosed path at a rate sufficient to prevent liquid accumulating in the sump, while

Abstract: The present invention relates to an improved continuous process for the preparation of mononitro-aromatic compounds which comprises (1) nitrating a reactive aromatic compound in the absence of sulphuric acid until mono-nitration is essentially complete, said nitration being carried out in 40 to 68% strength by weight nitric acid, (2) separating mechanically the nitration reaction mixture into an inorganic phase and an organic phase, (3) washing of the organic phase with water and dilute alkali solution and subsequent separation of the unconverted starting material end of the adhering water by means of rectification (4) feeding the inorganic phase and, if necessary, the wash water of the first water wash of the organic phase, to a rectification column in which (a) water is withdrawn over the top (b) optionally a fraction which has a lower nitric acid content than the feed is withdrawn from a sidestream takeoff in the rectifying section of the column and (c) a fraction which has a higher nitric acid content tha

Abstract: .alpha.-Amino-.beta.'-nitroanthraquinone is prepared by reacting .alpha.,.beta.'-dinitroanthraquinone with ammonia in an ether, an aliphatic, a cycloaliphatic or an optionally alkyl-substituted aromatic hydrocarbon, water or a mixture of the foregoing.

Abstract: Aromatic mononitro compounds are prepared by nitrating aromatic compounds with nitric acid having a concentration between 70 and 100% by weight, working up of the nitration mixture in a rectification column and separation of the aromatic mononitro compound.In the nitration mixture and in the rectification column, depending upon the concentration of the nitric acid present, the ratio by weight of nitric acid plus water is controlled and not lowered below defined figures. Optionally water or nitric acid is introduced into the rectification column.

Abstract: Pure 1-nitroanthraquinone substantially free of dinitroanthraquinone is prepared by:1. Nitrating anthraquinone or a mixture which contains anthraquinone with at least 90% nitric acid at a temperature of at least 0.degree. C wherein the mole ratio of nitric acid to anthraquinone is less than 20 to 1;2. Stopping the reaction when the anthraquinone conversion is at least 50% by cooling the reaction mixture to a temperature of at most 20.degree. C and/or by adjusting the mole fraction of nitric acid in the reaction mixture to a value of at most 0.86;3. Precipitating 1-nitroanthraquinone by adjusting the mole fraction of nitric acid to a value of from 0.7 to 0.4 and/or by reducing the temperature to at most 20.degree. C; and4. Separating the precipitated 1-nitroanthraquinone and subjecting it to vacuum distillation.

Abstract: 1-Amino anthraquinone is prepared by reacting 1-nitro-anthraquinone with ammonia in water and/or an organic solvent and thereafter treating the 1-amino-anthraquinone imine formed with water thereby converting said imine into 1-amino anthraquinone.

Abstract: 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.degree. C up to the boiling point and cooling is by about 10.degree. to 200.degree. C to a temperature not below about 0.degree. C.

Abstract: 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.

Abstract: 1-AMINO- AND/OR 1,5- AND/OR 1,8-DIAMINO AND/OR 1-AMINO-6-NITRO AND/OR 1-AMINO-7-NITRO-ANTHRAQUINONE ARE PREPARED BY REACTING 1-NITRO- AND/OR 1,5- AND/OR 1,8- AND/OR 1,6- AND/OR 1,7-DINITRO-ANTHRAQUINONE WITH AMMONIA IN THE PRESENCE OF A NITRILE.

Abstract: Process for the preparation of 1-nitroanthraquinone by nitration of anthraquinone in the presence of highly concentrated nitric acid, characterised in that nitration is carried out at temperatures of 20.degree. to 80.degree.C, the reaction is terminated by lowering the nitric acid molar fraction in the reaction mixture to .ltoreq.0.85 by distilling off concentrated nitric acid and 1-nitroanthraquinone is precipitated by subsequently adjusting the nitric acid molar fraction to .ltoreq.0.7 to 0.4 and is separated off in a manner which is in itself known.

Abstract: Process for the preparation of 1,5- and/or 1,8-diaminoanthraquinone by reaction of 1,5- and/or 1,8-dinitroanthraquinone with ammonia in organic solvents, characterised in that the reaction is carried out in ethers, aliphatic or cycloaliphatic hydrocarbons or optionally alkyl-substituted aromatic hydrocarbons or in mixtures of these compounds.

Abstract: Process for the preparation of 1-aminoanthraquinone by reaction of 1-nitroanthraquinone with ammonia in organic solvents, characterised in that the reaction is carried out in ethers, aliphatic or cycloaliphatic hydrocarbons or optionally alkyl-substituted aromatic hydrocarbons.

Abstract: Process for the manufacture of pure 1-nitroanthraquinone, characterised in that a nitroanthraquinone mixture obtained by nitration of anthraquinone in the presence of inorganic acids and, optionally, lowering the molar fraction of the acids in the reaction mixture after isolation of the reaction products which have precipitated and, optionally, further measures, is subjected to a rectification.