The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 30, 1977
Filed:
Oct. 20, 1975
Gunter Gehrke, Cologne, DT;
Reinold Schmitz, Blecher, DT;
Hans-Samuel Bien, Burscheid, DT;
Helmut Herzog, Leverkusen, DT;
Bayer Aktiengesellschaft, Leverkusen, DT;
Abstract
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.