| abstract |
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° 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. n The dyes obtained by the process of the invention are particularly suitable for dyeing wool or polyamide materials. |