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Carboxylic acid and NH3 ? - Why not an amide? watch

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    Why can't this form an amide, creating a H2O as a by-product?

    Instead reacting to form an Ammounium salt ?

    Thanks

    (Basically my M/S says reject amide, and i drew an amide so i was wondering why)
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    I don't think the NH3 is a strong enough nucleophile to replace the OH group on the carboxylic acid. The only way I can think of forming amides form ammonia is with an acyl chloride.
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    (Original post by Mos Def)
    Why can't this form an amide, creating a H2O as a by-product?

    Instead reacting to form an Ammounium salt ?

    Thanks

    (Basically my M/S says reject amide, and i drew an amide so i was wondering why)
    Just a thought experiment:

    carboxylic acids are usually found in the deprotonated carboxylate anion form and thus the negative charge is spread over the COO group consequently making the C less positive. Also the delocalisation (from the resonance structure) confers a bit of stability and is usually energetically stable to keep it rather than adding another group. Thus you can only get it to react if, say, it is very strong nucleophile (guess?).
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    It's to do with the conditions, both groups ionise in water, proton transfer with the water would be much much faster than a nucleophilc attack from a hindered amine. if you wanted to get the amide, you would have to do it in an aprotic solvent and probably at high temperature to overcome the activation energy. Also water could open the amide as fast as could be formed
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    so its dependent on the nucleophillic strength of the NH3?
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    Yeh to get an amine from carboxylic acids, you can apparently heat it under reflux with ammonium carbonate. This forms CH3COONH4, water and carbon dioxide. Then dehydrating CH3COONH4 when heating yields CH3CONH2
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    ok thanks all
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    Wouldn't it just be an acid base reaction?
    Carbox acid is an acid.
    Ammonia is a base..
    So they react to form a salt?
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    Vaporize, it is indeed a salt formation, but there's no water...how comes?
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    i thought it did form an amide an a NaCl4 complex which remains
 
 
 
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