Abstract: The invention relates to a process for the preparation of 1,4-diaminoanthraquinone-2-sulfonic acid by sulfonating 1,4-diaminoanthraquinone or leuco-1,4-diaminoanthraquinone, which comprises carrying out the sulfonation at elevated temperature with oleum as sulfonating agent, with or without the addition of a Lewis base. The 1,4-diaminoanthraquinone-2-sulfonic acid is used in particular for synthesizing anthraquinoid disperse dyes for dyeing hydrophobic fibre materials.

Abstract: The invention relates to a process for the preparation of 1,4-diamino-2,3-dicyanoanthraquinone, starting from 1,4-diaminoanthraquinones, or salts thereof, of the formula ##STR1## wherein n is 0, 1 or 2. To introduce the two cyanide radicals, the starting material is treated, in the presence of an oxidizing agent, with a compound which donates cyanide ions. The process comprises using as solvent a mixture of a carboxamide, an N-alkylated carboxamide or a lactam and water, which mixture contains more than 10% by weight of water.1,4-Diamino-2,3-dicyanoanthraquinone is an important intermediate for the synthesis of textile dyes.

Abstract: The invention relates to a process for the preparation of aromatic hydroxy compounds, starting from the corresponding halogenated aromatic compounds and replacing the halogen atom or atoms by the hydroxyl group. The process comprises converting the halogenated aromatic compound into the hydroxy compound by treatment with concentrated sulfuric acid, with the addition of an aldehyde and at elevated temperature.The aromatic hydroxy compounds are used as intermediates, for example for the manufacture of disperse and vat dyes.

Abstract: The present invention relates to an advantageous novel process for producing 1-acylamino-3,4-phthaloylacridones by a hydrogenating ring-closure reaction of 1-acylamino-4-anilidoanthraquinone-2'-carboxylic acid esters.The ring-closure reaction according to the invention to the acridone ring is performed under mild conditions, with regard to temperature and alkalinity of the reaction medium, with the use of a hydrogenating catalyst. The first step to effect the ester formation can be carried out, as a single-vessel reaction, with the use of a polar solvent as the reaction medium, and of an alkylphosphoric acid dialkyl ester as the esterifying agent.

Abstract: The invention provides a process for the production of alkoxy-substituted polycyclic aromatic compounds from corresponding hydroxy-substituted compounds.

Abstract: A process for the manufacture of 1,4-diamino-5-nitroanthraquinone from 1,4-diaminoanthraquinone by nitration with mixed nitric and sulphuric acid, before which nitration a masking of the two amino groups to form 1,9-4,10-anthraquinone disulphonimide takes place, this intermediate being in turn split by hydrolysis after the nitration, which process comprises carrying out the masking of the 1,4-diaminoanthraquinone to form the 1,9-4,10-anthraquinone-disulphonimide with liquid sulphur trioxide and carrying out the entire nitration process by using liquid solvents which are inert towards the reactants.

Abstract: A process for the manufacture of 1,4-diamino-5-nitroanthraquinone from 1,4-diaminoanthraquinone by nitration with mixed nitric and sulphuric acid, before which nitration a masking of the two amino groups to form 1,9-4,10-anthraauinone-disulphonimide takes place, this intermediate being in turn split by hydrolysis after the nitration, which process comprises carrying out the masking of the 1,4-diaminoanthraquinone to form 1,9-4,10 anthraquinone-disulphonimide in concentrated sulphuric acid which can optionally contain dissolved SO.sub.3, or in concentrated phosphoric acid using liquid sulphur trioxide.