Process for the preparation of 1,4-diaminoanthraquinone-2-sulfonic acid

摘要

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.