The (R)-enantiomer of ibuprofen has a specific rotation of [$\alpha$]²⁰_D= -59. What proportion of enantiomers would be required to prepare an optically impure sample of ibuprofen with a specific rotation of +29.50?

Question

Quizplus · Accepted Answer

To achieve a specific rotation of +29.50, the mixture must have more of the (S)-enantiomer, which has a positive rotation. The given specific rotation of the (R)-enantiomer is -59, so the mixture must be 75% (S)- and 25% (R)- to achieve the desired rotation.

The (R)-Enantiomer of Ibuprofen Has a Specific Rotation of [ α\alphaα

The (R)-Enantiomer of Ibuprofen Has a Specific Rotation of [ $\alpha$