Percent Enantiomeric Excess Formula:
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Definition: Percent Enantiomeric Excess is a measurement of purity used for chiral substances. It reflects the percent to which a sample contains one enantiomer in greater amounts than the other.
Purpose: It helps chemists quantify the optical purity of chiral compounds, which is crucial in pharmaceuticals and asymmetric synthesis.
The calculator uses the formula:
Where:
Explanation: The absolute difference between mole fractions is multiplied by 100 to convert to percentage.
Details: In pharmaceuticals, different enantiomers can have different biological activities. High %ee ensures the desired enantiomer dominates.
Tips: Enter mole fractions of R and S enantiomers (values between 0-1, sum ≤ 1). The calculator will compute the %ee.
Q1: What does 100% ee mean?
A: It means the sample contains only one enantiomer (completely optically pure).
Q2: What does 0% ee mean?
A: It means the sample is a racemic mixture (equal amounts of both enantiomers).
Q3: How is this different from optical purity?
A: %ee and optical purity are often used interchangeably, though technically optical purity is based on observed rotation.
Q4: Can the sum of mole fractions exceed 1?
A: No, the sum of all mole fractions in a mixture must equal 1 (or less if other components are present).
Q5: How do I measure mole fractions experimentally?
A: Typically using chiral chromatography or NMR with chiral shift reagents.