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Topic: Acid - Base reactions  (Read 3843 times)

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Offline gsel

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Acid - Base reactions
« on: January 09, 2014, 06:24:56 AM »
How come these two reactions* are not likely to occur according to their pKa values?
* HCN + CH3CO2-NA+  --> NA+-CN + CH3CO2H
* CH3CH2OH +NA+-CN  --> CH3CH2O-NA+ + HCN

Thanks!

Offline TheUnassuming

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Re: Acid - Base reactions
« Reply #1 on: January 09, 2014, 01:00:43 PM »
Correct me if I'm wrong, but it looks like you have two equations showing the equilibrium between HCN and sodium acetate or acetic acid and sodium cyanide:

HCN + CH3CO2Na <-> NaCN + CH3CO2H

So given the pKa of the two protonated forms (HCN and CH3CO2H), only one of the reactions shown is most likely to occur.  That said its an acid/base equilibrium so technically the other does happen just very slowly and is almost immediately reversed by the other.
When in doubt, avoid the Stille coupling.

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