Bayer Aktiengesellschaft

Klaus Leverenz

Alois Gottschlich

Winfried Kruckenberg

Hans-Gunter Otten

Horst Berneth

Manfred Hoppe

Rainer Hamprecht

Horst Brandt

Henning Reel

Karl-Ludwig Moritz

Alois Gotteschlich

Cationic 1,3,4-thiadiazole dyestuff of the formula ##STR1## in which

Cationic 1,3,4-thiadiazole dyestuffs

Water-insoluble dyestuffs of the formula I ##STR1## wherein K denotes the radical of a coupling component of the aniline series,

Disperse azo dyestuffs containing a thiocyonate group

Azo compounds of the formula I ##STR1## where D=diazo component

Nonionic azo compounds in which the coupling component is a 3,4-dialkoxy

An azo dyestuff of the formula ##STR1## wherein D=a diazo component,

Process for the preparation of azo dyestuffs having an aniline-type

Azo dyestuffs of the formula ##STR1## wherein R.sub.1 denotes hydrogen, C.sub.1 -C.sub.4 -alkoxy or C.sub.1 -C.sub.4 -alkoxyethoxy and

Benzisothiazole azo dye for synthetic fibers

The azo dyestuff of the formula ##STR1## having the interplanar spacings D/.ANG. 3.13, 3.36, 4.85, 9.26 and 13.94 for the five strongest lines having the relative intensity use 98, 89, 82, 100 and 87 is distinguished, compared to known modifications by an increased dye bath stability.

Stable gamma-modification of a benzisothiazole azo dyestuff

Benzoisothiazole azo dyestuffs

An azo dyestuff suited for dyeing polyester, of the formula ##STR1## in which Hal is F, Cl, Br or I,

Halo-substituted amino-and substituted-sulphonamido-containing azo

Disperse dyestuffs of the formula ##STR1## in which R, R.sub.1 and R.sub.2 denotes alkyl,

Hydroxypyridone azo dyestuffs

The invention relates to a process for diazotizing aromatic amines which are not diazotizable, or only incompletely diazotizable, in aqueous media containing mineral acid. It is characterized in that the diazotization is effected by means of nitrosyl compounds in organic, dipolar, aprotic solvents which do not undergo a chemical reaction with the diazonium salts of the aromatic amines. The new process is distinguished by less contamination of the effluent.

Process for diazotizing aromatic amines

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

The invention relates to the preparation of azo dyestuffs which are free from sulphonic acid groups by diazotization, coupling and subsequent nucleophilic exchange of a halogen atom of the diazo component is in the o-position relative to the azo group. The process is characterized in that all the reaction steps are carried out in a neutral organic dipolar solvent, with the proviso that when using diazo components which are not diazotizable, or only incompletely diazotizable, in dilute aqueous mineral acids, the diazotization medium employed consists of aprotic solvents which do not undergo any chemical reaction with the diazonium salt of this component. The new process is distinguished by less contamination of the effluent.

Process for the preparation of azo dyestuffs

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

Klaus Leverenz