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:
Feb. 23, 1993
Filed:
Aug. 12, 1991
Paul Herzig, Basel, CH;
Ciba-Geigy Corporation, Ardsley, NY (US);
Abstract
There is disclosed a process for the preparation of compounds of formula ##STR1## wherein the symbols are as defined in claim 1, which process comprises dissolving a compound of formula ##STR2## in sulfuric acid, adding this solution to oleum and reacting the mixture in the temperature range from 10.degree. to 80.degree. C. until a sulfo group has been completely introduced, and, in an optional further step, subjecting the reaction mixture to further reaction in the temperature range from 100.degree. to 200.degree. C. to introduce a second sulfo group. The compounds of formula (1) obtainable by this process are useful intermediates for the synthesis of dyes and are particularly suitable diazo components for the synthesis of azo dyes.