9-2 Structure and Stability of Benzene Benzene -Benzene is unsaturated ■ Benzene is much less reactive than typical alkene and fails to undergo the usual alkene reactions Cyclohexene reacts rapidly with Br2 and gives the addition product 1,2-dibromocyclohexane Benzene reacts only slowly with Br2 and gives the substitution product CeHsBr Fe Br2 catalyst HBr Br Benzene Bromobenzene (Addition product) (substitution product) not formed Benzene ▪ Benzene is unsaturated ▪ Benzene is much less reactive than typical alkene and fails to undergo the usual alkene reactions ▪ Cyclohexene reacts rapidly with Br2 and gives the addition product 1,2-dibromocyclohexane ▪ Benzene reacts only slowly with Br2 and gives the substitution product C6H5Br 9-2 Structure and Stability of Benzene