E2W2 Prelab Ans

CH 241F EXPERIMENT #2 CHEMICAL RESOLUTION OF (±)-PHENYLSUCCINIC ACID WITH (-)-PROLINE Prelab Week 2 1. Find out the expe...

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CH 241F EXPERIMENT #2 CHEMICAL RESOLUTION OF (±)-PHENYLSUCCINIC ACID WITH (-)-PROLINE Prelab Week 2 1. Find out the expected specific rotation for (+)-phenylsuccinic acid and its enantiomer. The following values are at a c=1.0, with acetone as the solvent. S-(+): [α]20D = +168

R-(-): [α]20D = -168

2. If you measured the optical rotation of racemic phenylsuccinic acid, what would you expect to find? Explain briefly. A racemic mixture of the two enantiomers would cancel the rotations, so that [α]20D = 0, therefore optically inactive. 3. Could you use the melting point data of the two enantiomers to tell them apart? The melting points of pure (+) or (-) enantiomers are the same: 173-176 oC (enantiomers have the same physical properties EXCEPT how they react to plane polarized light). Does that mean that the racemate would have the same melting point? Hmmm……