Ciba-Geigy Corporation

Daniel Parisot

Walter Iff

Hans Schaller

Alois Puntener

The invention relates to a process for the preparation of asymmetrical 1:2 chromium complex dyes of not less than 90% purity and containing at least one water-solubilizing group, which process comprises reacting a mixture of two metallizable azo dyes that contain different diazo components and different coupling components, or a mixture of a metallizable azo dye and a metallizable azomethine dye, in the molar ratio of 0.85:1.0 to 1.2:1.0, with the proviso that only one of said two mixture components contains at least one water-solubilizing group, with a chromium donor, under pressure and at a temperature above 100.degree. C. and in the pH range from 0 to 2, and subsequently carrying out further reaction in a weakly acid, neutral or weakly alkaline pH range, utilizing a single vessel for all steps. The dyes obtained by the process of the invention are particularly suitable for dyeing wool or polyamide materials.

Preparation of 1:2 chromium complex azo dyes asymmetrically substituted

The invention relates to a process for the preparation of 1:2 metal complex azo dyes of formula ##STR1## wherein each X is hydrogen, halogen or nitro, K and K' are each independently of the other the radical of a coupling component of the benzene, naphthalene or pyrazolone series, Y and Y' are each --O-- or --N(R), wherein R is hydrogen, C.sub.1 -C.sub.4 alkyl or phenyl, Me is chromium or cobalt and Ka is a cation, and Y and Y' are attached to K and K' adjacent to the azo group, by coupling and metallising, which process comprises coupling, in aqueous solution, a diazo component of formula ##STR2## wherein X is as defined for formula (1), in the presence of the 5- to 30-fold molar amount of sodium and/or potassium chloride, based on the molar amount of diazo component, and in the presence of a compound that donates a chromium or cobalt atom, to coupling components of formulae

Preparation of 1:2 metal complex dyes by coupling in the presence of a

The invention relates to a process for the preparation of asymmetrical 1:2 chromium complex azo dyes of not less than 90% purity and containing at least one water-solubilizing group, which process comprises reacting a mixture of two metallizable azo dyes that contain identical diazo components or identical coupling components, in the molar ratio of 0.85:1.0 to 1.2:1.0, with the proviso that only one of said two azo dyes contains at least one water-solubilizing group, with a chromium donor, under pressure and at a temperature above 100.degree. C. and in the pH range from 0 to 2, and subsequently carrying out further reaction in a weakly acid, neutral or weakly alkaline pH range, utilizing a single vessel for all steps The dyes obtained by the process of the invention are particularly suitable for dyeing wool or polyamide materials.

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Saint Genis Laval, France

Daniel Parisot