Question

Determine the enantiomeric excess of this lab experiment:

NOTE: Please be through in your explaination

Racemic - NaBH4 Reduction

Wavelength - 588.8 nm / Degrees- 12. 7 millidegrees

note: (not sure of importance): product 4.456 g product with 2ml of chloroform

Chiral - Enzymatic Reduction

Wavelength - 588.8 nm / Degrees- 381. 67 millidegrees

note: (not sure of importance): product 0.545 g product with 2ml of chloroform

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Knowns:

R

C6H12O3 is 132.16 g/ml / -46 degrees

S

CH3CH(OH)CH2CO2C2H5 IS 132.16 g/ml / + 46 degrees

Answer 1

NaBH4 reduction :

enantiomeric excss ee is given by formula

ee = ( 100 x observed rotation ) / ( specific rotation of isomer whose value is nearer to oberved)

since osbserved is 12.7 millidegres = 0.0127 degress is nearer to R we use R value

ee = ( 100 x 0.0127 /46)   = 0.0276 %

R isomer = ( 100 + ee) /2 = ( 100+0.0276 )/2 = 50.007 % , S = 49.993 %

Enzymatcic reduction , we have osberved rotation = 381.67 milli degress = 0.38167 deg

ee = ( 100 x 0.38167 /46) = 0.83 %

R = ( 100 + 0.83) /2 = 50.4 % , S = 49.6 %