How to Solve Enantiomeric Excess Related Numerical Problems – Part 1

Enantiomeric excess (ee) is a purity quantification for chiral compounds in stereochemistry and reflects the degree to which a sample contains one enantiomer in greater amounts than the other.


A racemic mixture has an ee of 0%, while a single completely pure enantiomer has an ee of 100%. So, for one, a sample with 70% of one enantiomer and 30% of the other has an ee of 40%.

ee is used as one of the indicators of success of an asymmetric synthesis.

ee is defined as the absolute difference between the mole fraction of each enantiomer.



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Question:

Calculate the enantiomeric excess of the mixture containing 6 g of (+)-2-Butanol & 4 g of (─)-2-Butanol.

Solution:




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Eerie enantiomeric excess❓ Let Chemaficionado know in the comments below or at mychemistryhomework@gmail.com❗

References:

(1)    Brown, C.; Ford, M. Higher Level Chemistry, 2nd ed.; Pearson Education: Harlow, Essex, 2014.

(2)    Ncert. Chemistry : Textbook for Class XII - Part.I; National Council Of Educational Research And Training: New Delhi.

(3)    Optical Rotation; 2019. https://en.wikipedia.org/wiki/Optical_rotation.

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