Patent · US Expired

Process for the isolation of 1-naphthylamine-4,8-disulphonic acid

US4407762A · kind A · utility

2Cited by

3References

9Claims

0Family size

Assignee

BAYER HEALTHCARE LLC · DE

Inventors

Heinz U. Blank · Odenthal, DE
Horst Behre · Odenthal, DE
Hans W. Linden · Leverkusen, DE
Werner Mentzel · Cologne, DE

Key dates

Filing date	Aug 23, 1982
Grant date	Oct 4, 1983
Priority date	—
Expiry date	Aug 23, 2002

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC07C303/44
WIPO fieldOrganic fine chemistry
WIPO sectorChemistry

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.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.