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US 4,801,695 AGranted
Iron complexes of azo dyes obtained from naphthylsulfonic acid, resorcinol and nitroaminophenol
AssigneeCiba-Geigy Corporation
InventorAlois Puntener
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Abstract
Iron complex dyes which are particularly suitable for dyeing leather in brown shades are obtained by coupling a naphthylaminesulfonic acid with resorcinol, subsequently coupling the reaction product with 4-nitro-2-aminophenol and metallizing with an iron compound.
Claims8
An iron complex of an azo dye prepared by diazotizing a naphthylamine sulfonic acid selected from the group consisting of 2-naphthylamine-5-sulfonic acid, 2-naphthylamine-6-sulfonic acid, 2-naphthylamine-7-sulfonic acid 2-naphthylamine-8-sulfonic acid;
- coupling the resulting diazonium compound with resorcinol at a pH of from 3 to 7 to form the first coupling-reaction product;
- subsequently coupling the first coupling reaction product with diazotized 4-nitro-2-aminophenol to form the second coupling-reaction product;
- and metallizing the second coupling-reaction product with an iron compound.
An iron complex of an azo dye prepared by:
- (a) coupling diazotized 2-naphthylamine-6-sulfonic acid with resorcinol at a pH of from 4 to 6, the molar ratio of said sulfonic acid used to resorcinol used being 1.0 to 1.2;
- (b) subsequently coupling the product of step (a) with diazotized 4-nitro-2-aminophenol at a pH from 8 to 10, the molar ratio of said 4-nitro-2-aminophenol used to resorcinol used being 0.95 to 1;
- and
- (c) metallizing the product of step (b) with iron (III) chloride, nitrate or sulfate, the molar ratio of said iron compound used to resorcinol used being 0.5 to 0.6.
1 more element
Dependencies are inferred from the claim text.