process for the production of kernbromierten polystyrolen with a bromgehalt of 70 to 80

摘要

Highly brominated polystyrenes are prepared by reacting phenylethyl bromide with bromine in a solvent in the presence of a halogenation catalyst, subsequently eliminating hydrogen bromide from the bromination product using alkali, and subsequently polymerising the material. After the halogenation catalyst has been destroyed and the excess bromine has been removed, the solvent is removed by distillation from the reaction mixture in which the phenylethyl bromide has been reacted with bromine in a solvent. The distillation residue is taken up in an alcoholic solvent and reacted with aqueous alkali-metal hydroxide or carbonate solution. After the added water has been expelled and the polymerisation has subsequently been initiated catalystically, the resultant highly-brominated polystyrene is removed from the reaction mixture. In a preferred embodiment, this preparation process can be carried out within a single reaction vessel without isolation of the intermediates. The highly brominated polystyrenes are used as flameproofing agents for plastics.