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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: 123456789 on September 06, 2012, 12:02:44 AM

Title: Why doesn't ethanol react with NaOH?
Post by: 123456789 on September 06, 2012, 12:02:44 AM
Ethanol is able to react with Na (s), but not NaOH (aq)
Why is it so?
In aqueous NaOH, there are mobile Na+ and OH-, so shouldn't alcohol be able to react with Na+ to form water and salt too, as it can be considered as an acid?
Title: Re: Why doesn't ethanol react with NaOH?
Post by: Guitarmaniac86 on September 06, 2012, 12:45:50 AM
They do react but the problem is, the alcohol reforms.

The aqueous NaOH reacts with your alcohol to form C-O-Na+ and water. The ethoxide ion will react with... water reforming the alcohol. These are in equilibrium so effectively, the net reaction is no reaction because the ethanol reforms.

Also, the pKa of sodium hydroxide may not be high enough to deprotonate ethanol to form your ethoxide... However, I cannot find a decent pKa table to compare the pKa of ethanol with sodium hydroxide.
Title: Re: Why doesn't ethanol react with NaOH?
Post by: orgopete on September 06, 2012, 01:51:38 AM
You should be able to calculate the equilibrium amount of NaOEt and H2O present if solid NaOH were added to ethanol.
Title: Re: Why doesn't ethanol react with NaOH?
Post by: AWK on September 06, 2012, 03:47:26 AM
http://faculty.swosu.edu/william.kelly/pdf/ch17.pdf
Title: Re: Why doesn't ethanol react with NaOH?
Post by: AC Prabakar on September 06, 2012, 03:51:21 AM
Quote from: AWK on September 06, 2012, 03:47:26 AM
http://faculty.swosu.edu/william.kelly/pdf/ch17.pdf

nice study material! Thanks for sharing....
Title: Re: Why doesn't ethanol react with NaOH?
Post by: Babcock_Hall on September 06, 2012, 10:25:07 AM
Quote from: AWK on September 06, 2012, 03:47:26 AM
http://faculty.swosu.edu/william.kelly/pdf/ch17.pdf
There is some very good material here, but there is also a typo.  "The O-H and S-H bonds of alcohols and thiols are able to undergo homolytic cleavage to give a proton and the conjugate base."  The author must mean heterolytic cleavage.
Title: Re: Why doesn't ethanol react with NaOH?
Post by: helper on November 18, 2013, 03:10:19 PM
This material is very helpfull! Thank you!
Title: Re: Why doesn't ethanol react with NaOH?
Post by: AlphaScent on November 18, 2013, 03:16:47 PM
Just printed that.

Thanks AWK!!

Title: Re: Why doesn't ethanol react with NaOH?
Post by: Altered State on November 18, 2013, 03:21:03 PM
Related useful stuff:

http://evans.harvard.edu/pdf/evans_pka_table.pdf