Preparing Alkenes:A Preview of Elimination Reactions Dehydrohalogenation Loss of HX from alkyl halide Usually occurs by reaction of an alkyl halide with a strong base H Br KOH KBr CH3CH2OH H20 H H Bromocyclohexane Cyclohexene (81%) Dehydrohalogenation ▪ Loss of HX from alkyl halide ▪ Usually occurs by reaction of an alkyl halide with a strong base Preparing Alkenes: A Preview of Elimination Reactions