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:
Apr. 22, 1980
Filed:
Sep. 29, 1978
Bernt Bonath, Muttenz, CH;
Sebastian Staubli, Magden, CH;
Hans Horisberger, Muttenz, CH;
Istvan Szekely, Basel, CH;
Ciba-Geigy AG, Basel, CH;
Abstract
A process for the production of amino-I-acid (2-naphthylamino-5,7-disulfonic acid) starting from Tobias acid (2-naphthylamine-1-sulfonic acid), which comprises sulfonating Tobias acid with fuming sulfuric acid (oleum) isothermically at room temperature, further sulfonating the resulting 2-naphthylamine-1,5-disulfonic acid without isolation, by rapidly heating the reaction mixture to 110.degree. to 140.degree. C. to give 2-naphthylamine-1,5,7-trisulfonic acid, hydrolyzing the trisulfonic acid in sulfuric acid having a concentration between 80 and 98%, at a temperature of 100.degree.-180.degree. C., to give the amino-I-acid, precipitating this latter from dilute sulfuric acid and isolating it from the reaction mixture, and the amino-I-acid obtained by this process.