July 02, 2022, 02:13:08 PM
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Topic: Need help interpreting this NMR spectrum (reduction of camphor to isoborneol)  (Read 7027 times)

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Offline thescepticalchymist

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This is the NMR spectrum we were given for the final product of the synthesis: https://imgur.com/gallery/wFfnKQD.  It seems to contain both borneol and isoborneol, or at least that's what my friend told me. 
Basically, what the spectrum is showing are the differences in chemical environment between the hydroxyl groups of each isomer, right?  The first peak (borneol) is at 3.9-3.8 ppm and has an integration of 0.847 --- what exactly does that number signify?  Anything about the percent composition of the mixture?  The isoborneol peak, on the other hand, has an integration of 4.110, which I guess indicates that it is the major product.
As for why isoborneol is the major product, I guess it has to do with the fact that the hydroxyl group in that isomer is at the equatorial position, reducing the steric hindrance.  Correct me if I'm wrong.

Offline sjb

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Seems sensible. As to what the 0.847 (or 4.110) represents  - what does any integral in a proton NMR represent?

Offline Babcock_Hall

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Not every reaction will produce the more stable isomer as the major product.  You may have encountered the phrases "kinetic product" and "thermodynamic product" at some point.  I am not sure whether or not this distinction applies in the present situation.

Offline Babcock_Hall

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http://www.chemicalforums.com/index.php?topic=23789.0

There was a similar thread a long time ago.

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