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Topic: Which are the most acidic ?  (Read 4848 times)

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Offline shalikadm

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Which are the most acidic ?
« on: June 22, 2012, 03:18:32 PM »

In the first one there's two deactivators while the second one has only one.But the second one has more electronegative element F as the deactivator..So how can I choose the most acidic ?

Offline Nescafe

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Re: Which are the most acidic ?
« Reply #1 on: June 22, 2012, 03:42:46 PM »
I would say the dichloro due to the fact that the electronegativity of F is about 4.0, that of Cl is 3.0. There is one unit difference but there are two Cls v.s. one F. I do not think they are much different though.

Offline orgopete

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Re: Which are the most acidic ?
« Reply #2 on: June 22, 2012, 06:43:09 PM »
The chloropropionic acid should be more acidic. I compared the dichloro with monofluoroacetic acids and the dichloroacetic acid was more acidic, 1.29 vs 2.66, see http://research.chem.psu.edu/brpgroup/pKa_compilation.pdf

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Offline cheese (MSW)

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Re: Which are the most acidic ?
« Reply #3 on: June 23, 2012, 12:26:41 PM »
CH3CCl2CO2H 2,2-dichloropropionic acid   pKa = 1.68
CH3CHFCO2H  2-fluoropropionic acid    pKa = 2.68
CAS

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