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Topic: Why are ethers unreactive?  (Read 7129 times)

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Offline joyb

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Why are ethers unreactive?
« on: February 26, 2013, 10:01:47 AM »
I would think that their high polarity would make the oxygen atom very susceptible to hydrolysis. Why are they so unreactive? Steric hindrance?

Offline Babcock_Hall

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Re: Why are ethers unreactive?
« Reply #1 on: February 26, 2013, 10:27:11 AM »
Draw out the mechanism and ask yourself what the leaving group would be.

Offline joyb

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Re: Why are ethers unreactive?
« Reply #2 on: February 26, 2013, 02:35:34 PM »
So is it just that the leaving group would have to be an alkyl group?

Offline Altered State

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Re: Why are ethers unreactive?
« Reply #3 on: February 26, 2013, 02:55:30 PM »
So is it just that the leaving group would have to be an alkyl group?

Isn't it good enough reason?

Offline Babcock_Hall

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Re: Why are ethers unreactive?
« Reply #4 on: February 26, 2013, 05:09:15 PM »
So is it just that the leaving group would have to be an alkyl group?
I pictured diethyl ether in my mind, and I may be thinking of a different chemical process than you are.  If solvent attacked the carbon atom of the -CH2- group, then ethoxide would be the leaving group.  This would not be a fast process.

Offline camptzak

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Re: Why are ethers unreactive?
« Reply #5 on: February 27, 2013, 12:35:29 AM »
What pH (acid or base) do ethers hydrolyze at? I found a paper that might contain the answer but I do not have access!
http://pubs.acs.org/doi/abs/10.1021/ie0702882
"Chance favors the prepared mind"
-Louis Pasteur

Offline Altered State

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Re: Why are ethers unreactive?
« Reply #6 on: February 27, 2013, 09:59:07 AM »
What pH (acid or base) do ethers hydrolyze at? I found a paper that might contain the answer but I do not have access!
http://pubs.acs.org/doi/abs/10.1021/ie0702882

Always Acid Media to break an ether C-O Bond, and it's always broken the less substituted Carbon bond.
What pH? It depends on the ether.
For example, dibuthyl ether would be way easier to hydrolyze than diphenylether (which one is extremelly difficult).

You also have to consider the exception of epoxides, that can be easily opened both in basic media (less substituted C) and acid media (most substituted).

Offline Babcock_Hall

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Re: Why are ethers unreactive?
« Reply #7 on: February 27, 2013, 10:32:39 AM »
At room temperature, the reaction is specific-acid catalyzed, according to the paper.

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