Uses of Bromine. Bromine compounds are used as pesticides, dyestuffs, water purification compounds, and as a flame-retardants in plastics. 1,2-dibromoethane is used as an anti-knock agent to raise the octane number of gasoline and allow engines to run more smoothly.romine compounds are used as pesticides, dyestuffs, water purification compounds, and as a flame-retardants in plastics. 1,2-dibromoethane is used as an anti-knock agent to raise the octane number of gasoline and allow engines to run more smoothly.