When (R)-2-bromobutane is heated in water ,the sn1substitution proceeds twice as fast as sn2 . calculate the appropriae enantiomeriexcess and the specific rotation of the product. The specific rotation of r-butanolis +13.5

Dear Student,

When (R)-2-bromobutane is heated in water, the SN1 substitution reaction occurs which produces a racemic mixture of (R)-2-butanol and (S)-2-butanol. Since a racemic mixture contains equal amounts of both the enantiomers, therefore, the sepecific rotation of one enantiomer cancels out the specific rotation of other enantiomer i.e. R-Butanol has specific rotation +13.5, so S-Butanol will have specific rotation -13.5.
The overall specific rotation for the mixture is +13.5+(-13.5)=0
Enatiomeric excess, ee=specific rotation of mixturespecific rotation of pure enatiomer×100or, ee=0-13.5×100=0i.e. the enantiomers are in equal quantity.


  • -2
What are you looking for?