Question

A sample of limonene has a specific rotation of +71.3 R-(+)-limonene [dD = + 125.6" and, S-(-)-limonene [a]D--1 22. 1 ®. What is the % ee? Number %ee What is the molecular composition of this same sample? Number s isomer = 1 % 1Somer Number R isomer-

Answer 1

% ee = specific rotation / [A]D * 100

% ee = 71.3 / 125.6 * 100

% ee = 56.767 %

molar compositon of sample is

let R isomer is X percent

then

X*125.6 - (1-X)(-122.1)= 71.3

x(125.6 +122.1) -122.1 = 71.3

x = (71.3 + 122.1)/(125.6+122.1)

X = 0.78078

then R --> 78%

for S

S = 100-78 = 22%

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