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. 03, 1982
Filed:
Feb. 22, 1980
Applicant:
Inventors:
Werner Steinbeck, Cologne, DE;
Gunter Gehrke, Cologne, DE;
Assignee:
Bayer Aktiengesellschaft, Leverkusen, DE;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C07C / ;
U.S. Cl.
CPC ...
260383 ;
Abstract
95-99% pure 4,5-dinitro-1,8-dihydroxyanthraquinone which is essentially free from by-products is obtained by 'direct nitration' of 1,8-dihydroxyanthraquinones or 1,8-dimethoxyanthraquinones if the concentrations of acid are chosen such that, when the nitration reaction and, if appropriate, the saponification reaction have ended, an 80-100% strength sulphuric acid is present, or such a sulphuric acid concentration is established by adding water, and the 4,5-dinitro-1,8-dihydroxyanthraquinone which crystallizes out is separated off.