What does mean a 94% enantiomeric excess? The product contains 94% of one enantiomer The and 6% of the other enantiomer product contains 94% of one enantiomer and 6% The product of other products contains an enantiomer which is 94% pure. The product contains 97% of one enantiomer and 3% of the other enantiomer
The Correct Answer and Explanation is:
The correct answer is:
The product contains 94% of one enantiomer and 6% of the other enantiomer.
Explanation
Enantiomeric excess (ee) is a term used in stereochemistry to describe the purity of a chiral compound in terms of its enantiomeric composition. A chiral molecule has two enantiomers—mirror images that are not superimposable, much like your left and right hands. When a reaction produces one enantiomer in greater proportion than the other, the mixture is said to have an enantiomeric excess.
Mathematically, enantiomeric excess is calculated as: ee=∣%major enantiomer−%minor enantiomer∣\text{ee} = \left| \% \text{major enantiomer} – \% \text{minor enantiomer} \right|
In this case, an enantiomeric excess of 94% means that the difference between the amounts of the two enantiomers is 94%. This implies the product is composed of:
- 94% more of the major enantiomer than the minor one, and
- The remaining 6% corresponds to the minor enantiomer.
To find the actual percentages of each enantiomer in the mixture, we use the fact that the total must add up to 100%. If the ee is 94%, the rest of the mixture (100% – 94% = 6%) is a racemic mixture—equal parts of both enantiomers—adding 3% to each enantiomer.
Thus, the final composition is:
- 94% + 3% = 97% of the major enantiomer
- 3% of the minor enantiomer
However, enantiomeric excess is typically expressed as the difference, not the absolute composition. So if a compound has 94% ee, it must contain 94% of one enantiomer and 6% of the other.
This concept is important in pharmaceutical chemistry because different enantiomers of a drug can have different biological effects. A high enantiomeric excess indicates high stereoselectivity and purity, which is often desirable for efficacy and safety.
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