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:
Oct. 11, 1988
Filed:
Mar. 19, 1986
Applicant:
Inventor:
Bruno Fortsch, Ramlinsburg, CH;
Assignee:
Ciba-Geigy Corporation, Ardsley, NY (US);
Attorneys:
Primary Examiner:
Int. Cl.
CPC ...
C07C / ; C07C / ;
U.S. Cl.
CPC ...
534557 ; 534558 ; 534559 ; 534562 ; 534565 ;
Abstract
The invention relates to a process for the preparation of 1-diazo-2-naphthol-4-sulfonic acid by diazotizing 1-amino-2-naphthol-4-sulfonic acid in weakly acid medium and in the presence of iron ions, using only 1 to 30 millimoles of an iron compound per mole of 1-amino-2-naphthol-4-sulfonic acid. Such an insignificant amount is sufficient to protect the 1-amino-2-naphthol-4-sulfonic acid effectively from being oxidized to 1,2-naphthoquinonesulfonic acid and to afford the desired reaction product in good yield.