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Topic: Dehydration of Methylcyclohexanols  (Read 3695 times)

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Dehydration of Methylcyclohexanols
« on: November 21, 2010, 12:19:17 AM »
I started out with 2-methylcyclohexanol and made 1-ethylcyclopentene and 3-ethylcyclopentene in miniscule amounts. Can anyone explain the mechanism of the formation of these two products to me? How could it have happened, and what must have rearranged?
Thanks

Offline MissPhosgene

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Re: Dehydration of Methylcyclohexanols
« Reply #1 on: November 21, 2010, 12:26:25 AM »
I assume you used a strong acid as the dehydrating agent.

What happens when you put an alcohol in strong acid? Can you possibly draw any alkyl shifts which result in ring contraction?
Stereograms of the 32 crystallographic point groups: little bike wheels of cold, hard, pure rationality.

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Re: Dehydration of Methylcyclohexanols
« Reply #2 on: November 21, 2010, 12:32:44 AM »
Yes, I used concentrated phosphoric acid for the reaction.
I know the mechanisms of the formation of 1-methylcyclohexene, 3-methylcyclohexene and methylenecyclohexane, which make up most of the product, but I don't know how to get the others.
No, I don't know how to draw any ring contractions. Are there any resources I can use, or would could you explain how it works?

Offline MissPhosgene

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Re: Dehydration of Methylcyclohexanols
« Reply #3 on: November 21, 2010, 01:01:35 AM »
Do you know why the cyclopentenes are minor products and the six membered rings are the major products?
If not, look up alkyl and hydride shifts.
Stereograms of the 32 crystallographic point groups: little bike wheels of cold, hard, pure rationality.

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