Which is the stronger base among "NaOEt" (sodium acetate) and "LDA" (lithium diisopropylamide)?

1 Answer
Mar 15, 2016

In decreasing basicity

"LDA" > "NaOEt" > "NaOAc"

Explanation:

Sodium acetate is written as "NaOAc", with chemical formula

https://upload.wikimedia.org/wikipedia/commons/4/45/Sodium-acetate-2D-skeletalpng

Not "NaOEt", which is called sodium ethanoxide and has a chemical formula

https://upload.wikimedia.org/wikipedia/commons/4/4a/Sodium_ethoxidepng

"NaOAc" is not a strong base as the negative charge can be delocalized among the 2 oxygens.

To compare whether "LDA" or "NaOEt" is more basic, we can consider two reactions

  1. Ethanol + LDA.

  2. Sodium ethanoxide + diisopropylamine (conjugate acid of LDA)

The first reaction proceeds much further than the second one.

LDA can only be formed from treatment of diisopropylamine with n-butyllithium, which is much more basic than sodium ethanoxide.

From this, we conclude that LDA is more basic than sodium ethanoxide.

So the final result, in decreasing basicity

"LDA" > "NaOEt" > "NaOAc"

For stronger evidence, please refer to their "p"K_"a" values.