Vanadium-Catalysed Oxidative Bromination Using Dilute Mineral Acids and Hydrogen Peroxide: An Option for Recycling Waste Acid Streams

Vanadium pentoxide, V2O5, catalyses the two-electron oxidation of Br- to Br+, using aqueous hydrogen peroxide under dilute acidic conditions. In this system, kinetic studies show that HBr can be replaced with a combination of an alkali bromide salt (NaBr, KBr) and a dilute mineral acid (e.g., HCl, H2SO4, HNO3, H3PO4). The salt/acid/peroxide system may be used for in situ or ex situ oxidative bromination, e.g. of various aromatic compounds. The application of the above concept towards the recycling of industrial acid waste is discussed. The cost effectiveness, E factors, and hazard factors for several bromination and oxidative bromination reagent systems are compared.