Energy Comparisions For Different OChem Structures

[justadream]

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I'm reading TBR Ochem chapter about "structure elucidation". It discusses why certain structures are more favorable over others.

For example, it says that for methylcyclohexane, equatorial is favored over axial. I get that. What I am unclear about is the energy difference it provides.

TBR writes:

"Equatorial > Axial by 1.69 kcals/mol"

What energy is this 1.69 kcals/mol referring to? I'm unclear about why something that is more favorable would have "higher energy"?

 

[sillyjoe]

I don't have this chapter in front of me but what I think they mean is that methylcyclohexane gives off 1.69 kcals/mol energy every time it goes from the axial to the equatorial position and it needs 1.69 kcals/mol input of energy to go from the equatorial position to the axial position

axial methylcyclohexane --> equitorial methylcyclohexane + 1.69 kcal

equitorial methylcyclohexane + 1.69 kcals --> axial methylcyclohexane

 

[justadream]

That seems to be an intuitive explanation. Thanks!