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. 04, 1983
Filed:
Aug. 23, 1982
Heinz U Blank, Odenthal, DE;
Horst Behre, Odenthal, DE;
Hans W Linden, Leverkusen, DE;
Werner Mentzel, Cologne, DE;
Bayer Aktiengesellschaft, Leverkusen, DE;
Abstract
Process for the isolation of 1-naphthylamine-4,8-disulphonic acid from sulphonation mixtures containing it according to which process the sulphonation mixture is introduced into preheated water in such a manner that, at the start of crystallization, a temperature of at least 100.degree. C. is reached and the 1-naphthylamine-4,8-disulphonic acid is separated from the mother liquor at a temperature not higher than 70.degree. C. The process is applied particularly advantageously for the isolation of 1-naphthylamine-4,8-disulphonic acid from sulphonation mixtures which have been obtained by introducing in turns alkali metal sulphate, 1-naphthylamine-8-sulphonic acid and SO.sub.3 into sulphuric acid which has been introduced initially, a total of 1.5 to 3 mols of SO.sub.3 and 0.6 to 1.5 mols of alkali metal sulphate being employed per mol of 1-naphthylamine-8-sulphonic acid.