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:
May. 29, 1990
Filed:
May. 12, 1989
Bernhard Albrecht, Buus, CH;
Jurgen Beyrich, Huttingen, DE;
Ciba-Geigy Corporation, Ardsley, NY (US);
Abstract
There is disclosed an improved semi-continuous and continuous process for the preparation of 1-amino-2-naphthol-4-sulfonic acid by nitrosation of 2-naphthol, addition of bisulfite, acidification with mineral acid and reduction of the reaction product so obtained, which comprises charging the reactor with the nitrosating agent and simultaneously adding 2-naphthol and mineral acid simultaneously in separate streams in the semi-continuous process, or charging the reactor with the reaction mass and simultaneously adding 2-naphthol, mineral acid and the nitrosating agent in separate streams in the continuous process. The product can be further used, without isolation, for the synthesis of dyes.