Bayer Aktiengesellschaft

Alois Gottschlich

Klaus Leverenz

Karl-Ludwig Moritz

Azo dyestuff having the formula ##STR1## in which A is an aromatic carbocyclic radical containing a CN substituent in the o-position to the azo group and K is the radical of a coupling component as well as the process for their production are disclosed. The process involves cyano exchange between a metal cyanide, e.g. CuCN and the corresponding dyestuff containing Cl or Br instead of CN, in an organic solvent particularly polar aprotic organic solvents, e.g. dimethyl sulfoxide. The dyestuffs are suitable for dyeing a variety of fiber material such as cotton, wool, silk as well as synthetic materials such as polyamide and polyethylene terephthalate to give dyeings which are characterized by great clearness and good general fastness properties.

Monoazo dyestuff containing di-cyano substituents ortho to the azo group

Azo dyestuff of the formula ##STR1## wherein R.sub.5 is H, CH.sub.3, OCH.sub.3, or OC.sub.2 H.sub.5 ;

Phenyl-azo-anilino dyestuff

Phenylazo orthocyano phenylazo or orthocyano phenylazo phenylazo

Preparation of azo dyestuffs which possess at least one nitrile group in the ortho-position to the azo bridge, by reacting the corresponding ortho-halogenoazo compounds with CuCN or systems which for CuCN, in the presence of nitrogen bases and optionally of surface-active agents, in an aqueous medium, with replacement of at least one halogen substituent, which is in the orthoposition to the azo bridge, by a nitrile group. Preferably the reaction is carried out as one-pot-process. The dyestuffs prepared by the process, a substantial number of which are known, are useful in dyeing natural and synthetic fiber materials.

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Leverkusen, Germany

Alois Gottschlich