Basf Aktiengesellschaft

Wolfgang Schulte

Herbert Naarmann

Klaus Penzien

Guenter Hansen

Franz Brandstetter

Georg Zeidler

Axel Nissen

Horst Scheuermann

Gerhard Lindenschmidt

Harald Laas

Hans-Joachim Opgenorth

Hans-Richard Mueller

Trisazo dyes containing sulfo groups and having the formula: ##STR1## which for the most part give black colorations on paper and particularly on leather and are therefore especially useful as leather dyes.

Trisazo dye

A mixture of brominated oligomeric polystyrenes, having a degree of polymerization of from 3 to 400, and low molecular weight brominated aromatic compounds of the diphenyl ether type is obtained by polymerizing the non-brominated starting materials, in a halohydrocarbon solvent, using a Lewis acid catalyst. The reaction mixture is then brominated and extracted with water to remove hydrogen bromide and catalyst, and the solvent and volatile constituents are separated from the product. The bromination is carried out at from -30.degree. C. to +130.degree. C. The final mixtures have a low melt viscosity and are therefore particularly suitable for incorporation, as a flameproofing agent, into thermoplastics.

Preparation of mixtures of brominated polystyrenes and brominated

A process for the preparation of an indolenine of the general formula I ##STR1## where R, R.sup.1 and R.sup.2 are aliphatic radicals and R.sup.1 and R.sup.2 may also be linked and the ring A may be additionally substituted, wherein a compound of the formula II ##STR2## is heated in the presence of a Lewis acid and of a halide. The products are valuable starting compounds for the preparation of dyes.

Preparation of indolenines

Styrene polymers or copolymers containing bromine are manufactured by cationic polymerization of the monomer, or of the monomer plus a copolymerizable monomer of the isobutylene or nuclear-alkylated styrene type, in an organic solvent in the presence of a Lewis acid catalyst. Bromine is then added to the solution without first working up the latter. The catalyst used for the bromination is the same as that used for the polymerization. If necessary, fresh catalyst may be added before the bromination. After completion of the bromination the reaction solution is extracted with water until it is bromide-free, and the solvent, generally a halohydrocarbon, is then stripped off. Products containing up to about 80% by weight of bromine may be obtained. They have a pale yellowish color and exhibit no significant decomposition up to 340.degree. C. They may be used as flame-proofing agents for thermoplastics.

Manufacture of brominated polymerization products of styrene

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Hassloch, Germany

Wolfgang Schulte