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:
Jul. 14, 1987
Filed:
May. 09, 1986
Applicant:
Inventors:
Guido Skipka, Stolberg, DE;
Friedrich Durholz, Remscheid, DE;
Assignee:
Bayer Aktiengesellschaft, Leverkusen, DE;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C07C / ;
U.S. Cl.
CPC ...
2605 / ;
Abstract
4,4-40 -Dinitrostilbene-2,2'-disulphonic acid salts are prepared by the oxidation of 4-nitrotoluene-2-sulphonic acid or salts thereof in an aqueous alkaline medium, by adding potassium, calcium and/or magnesium ions during the reaction at the rate of which 4,4'-dinitrostilbene-2,2'-disulphonic acid is formed, the amount of added potassium, calcium and/or magnesium ions at any point during the reaction being 10 to 150 mol %, relative to the amount of 4,4'-dinitrostilbene-2,2'-disulphonic acid present in the reaction mixture at that particular time, and by removing the precipitated salt of 4,4'-dinitrostilbene-2,2'-disulphonic acid.