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Addition Reaction of Bromine to Cyclohexene


  • Bromine is highly toxic and reactive. Use care.
  • Both cyclohexane and cyclohexene are very flammable. Keep away from flames.
  • Cyclohexene and cyclohexane have an irritating odor.
  • Dichloromethane is a cancer suspect agent.

Chemicals and Solutions

  • Bromine solution (5% in dichloromethane)
  • Cyclohexane
  • Cyclohexene


2 hydrometer cylinders


  1. Fill 1 cylinder 1/2 full with cyclohexane and fill the other 1/2 full with cyclohexene.
  2. Add bromine solution to both cylinders. Bromine adds across the double bond of cyclohexene forming a clear solution of trans-1,2-Dibromocyclohexane. The cylinder containing cyclohexane remains colored.