Process for the preparation of 1,4-diaminoanthraquinone-2-sulfonic acid
AssigneeCiba-Geigy Corporation
InventorsMaurice Grelat, Rudolf Schaulin
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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.
Claims7
A process for the preparation of 1,4-diaminoanthraquinone-2-sulphonic acid by sulphonating 1,4-diaminoanthraquinone or leuco-1,4-diaminoanthraquinone, which comprises carrying out the sulphonation in a temperature range from 90.degree. to 150.degree. C. with oleum having a concentration of 20 to 70% as sulphonating agent in the absence of an insert organic solvent, where oleum is used in a concentration and amount such that the concentration of sulphur trioxide in the reaction mixture at the conclusion of reaction is between 10 and 30% by weight.
Dependencies are inferred from the claim text.