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Topic: SECONDARY ALCOHOL  (Read 3969 times)

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Offline alexalexmaiden

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SECONDARY ALCOHOL
« on: June 20, 2014, 12:06:23 PM »
can someone plz help me what is the product of a secondary alcohol + KOH and heat ?? thank you

Offline Babcock_Hall

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Re: SECONDARY ALCOHOL
« Reply #1 on: June 20, 2014, 12:29:24 PM »
You must show an attempt before we can help you.  What sorts of reactions do you think might occur?

Offline alexalexmaiden

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Re: SECONDARY ALCOHOL
« Reply #2 on: June 20, 2014, 12:32:18 PM »
the only thing that i can think about is dehydration... instead of OH > OK and water maybe??
« Last Edit: June 20, 2014, 12:45:01 PM by alexalexmaiden »

Offline Babcock_Hall

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Re: SECONDARY ALCOHOL
« Reply #3 on: June 20, 2014, 04:26:15 PM »
instead of OH > OK and water maybe??
I don't understand what you mean by the above phrase.  With respect to dehydration, that is what I thought at first, but the leaving group is terrible.

Offline alexalexmaiden

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Re: SECONDARY ALCOHOL
« Reply #4 on: June 20, 2014, 05:24:15 PM »
i dont know , i cant think of anything else

Offline Babcock_Hall

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Re: SECONDARY ALCOHOL
« Reply #5 on: June 21, 2014, 03:27:14 PM »
A base can always remove a proton.  Just thinking out loud.

Offline alexalexmaiden

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Re: SECONDARY ALCOHOL
« Reply #6 on: June 21, 2014, 06:31:55 PM »
i think that the product is alkene

Offline Hunter2

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Re: SECONDARY ALCOHOL
« Reply #7 on: June 22, 2014, 08:27:54 AM »
No, Alcohol can work like an acid. So what can it be.

Offline alexalexmaiden

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Re: SECONDARY ALCOHOL
« Reply #8 on: June 22, 2014, 04:23:18 PM »
the professor of my organic chemistry lessons said that... 2 pentanol + KOH and heat gives 2-pentene  ???

Offline spirochete

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Re: SECONDARY ALCOHOL
« Reply #9 on: June 22, 2014, 07:58:57 PM »
Either you've misunderstood your professor or your professor has made a mistake. Hydroxide will not be a leaving group in either an E2 or E1 reaction, so the product is not an alkene. The alcohol could act like an acid, although hydroxide is not a strong enough base to fully deprotonate an alcohol.  Thus there will be an equilibrium between the alkoxide and water and the hydroxide reagent and the alcohol.

Offline hypervalent_iodine

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Re: SECONDARY ALCOHOL
« Reply #10 on: June 22, 2014, 10:59:35 PM »
As others have said here, you will not get a dehydration reaction with a base and heat. For this to happen, you'd need a strong acid and heat. The hydrogen on the alcohol is very mildly acidic; if you were to put a base in with this alcohol, the base (if strong enough) will react with the acid and you end up with an alkoxide. We use this type of reaction in, for example, the Williamson ether synthesis.

Offline alexalexmaiden

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Re: SECONDARY ALCOHOL
« Reply #11 on: June 23, 2014, 05:58:42 AM »
ok ... understood, thank you

Offline Irlanur

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Re: SECONDARY ALCOHOL
« Reply #12 on: June 23, 2014, 08:06:28 AM »
An E1cb would in principle be possible, but I doubt that this works in this case.

Offline Babcock_Hall

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Re: SECONDARY ALCOHOL
« Reply #13 on: June 23, 2014, 10:41:13 AM »
I could imagine that a E1cB reaction would occur if the alcohol functional group were beta with respect to a ketone.
« Last Edit: June 23, 2014, 01:22:46 PM by Babcock_Hall »

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