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US 4,045,457 AGranted
Anthraquinone dyestuffs
AssigneeBayer Aktiengesellschaft
InventorsGunter Gehrke, Reinold Schmitz, Hans-Samuel Bien, Helmut Herzog
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AssigneeBayer Aktiengesellschaft
InventorsGunter Gehrke, Reinold Schmitz, Hans-Samuel Bien, Helmut Herzog
Estimating the term…
The invention relates to a process for the preparation of water-insoluble chlorine-containing diaminodihydroxyanthraquinone dyestuffs. The process consists in that 2,8-dichloro-1,5-dinitroanthraquinone and/or 2,5-dichloro-1,8-dinitroanthraquinone is warmed with sulphur in concentrated sulphuric acid having a maximum SO.sub.3 content of 20% - possibly in the presence of boric acid - the resulting compounds are, if appropriate, post-halogenated and/or alkylated, preferably in the same reaction batch. The main advantage of this process is that it starts from 1,6- and/or 1,7-dichloroanthraquinone, for which there was hitherto no industrial use, but which unavoidably also arise during the synthesis 1,5- and 1,8-dichloroanthraquinones.
Process for the preparation of ".alpha., .alpha.'-diamino-.alpha., .alpha.'-dihydroxy-.beta.-chloroanthraquinones" comprising warming 2,8-dichloro-1,5-dinitro-anthraquinone, 2,5-dichloro-1,8-dinitro-anthraquinone or mixtures thereof with sulfur in concentrated sulfuric acid or oleum having a maximum SO.sub.3 content of 20% in the presence of boric acid.
Dependencies are inferred from the claim text.