I'm having difficulty with this problem because there are two substituents, and in the in-class example there was only one substituent.
Here is the example used in class:
"Circle the structure of the conformer that will be present in greater amount."
t-butyl=4.9 kcal/mol. Since equatorial conformation is the product in this equilibrium, we use -4.9 kcal/mol.
equilibrium constant expression
K= [equitorial]/[axial]
at room temp deltaG=-1.36 log K The A-value is used for the deltaG term.
-4.9/-1.36=log K
K=10^3.60=4008 , K=[equitorial]/[axial]
Let X=the percentage of axial conformer
K=(100-X)/(X) 4008X=100-X
X=100/(K+1)=100/4009=.02%
percentage of equatorial conformer=100-X=99.98%
ANSWER=EQUATORIAL CONFORMER
here is the problem I'm having trouble with..
"Circle the structure of the conformer that will be present in greater amount."
A-values (in kcal/mol)
Ph=2.90
CO2H=1.40
Using product as the RIGHT side
-1.40/-1.36=log K
K=10^1.0294=10.70 , K=[equitorial]/[axial]
Let X=the percentage of axial conformer
K=(100-X)/(X) 11.70=100-X
X=100/(K+1)=100/11.70=8.54%
percentage of equatorial conformer=100-8.54=94.45%
ANSWER=AXIAL CONFORMER
however, if product is on the LEFT side
-2.90/-1.36=log K
K=10^2.132=135.629, K=[equitorial]/[axial]
Let X=the percentage of axial conformer
K=(100-X)/(X) 135.629=100-X
X=100/(K+1)=100/136.629=.7319%
percentage of equatorial conformer=100-.7319=99.26
ANSWER=EQUITORIAL CONFORMER
as you can see, I am running in circles because there can't be two answers. help is desperately needed..!