# Mechanism for formation of amides from ammonium carboxylate salts

One of the reactions that you can do with a carboxylic acid is to react it with ammonia or an amine, which produces the corresponding ammonium carboxylate salt. When this salt is heated, amide is obtained by elimination of water (although it seems that the yield is not that good). $$\ce{RNH2 + RCOOH->RCOO- ^+NH3R->(heat)->RCOONHR + H2O}$$ So what sort of mechanism can we draw for the elimination of water? It seems to me a bit complicated because the amine is already protonated in the salt, so it does not have any lone pair remaining for nucleophilic attack. Does the acid base reaction go backward under high temperatures? Or is it something else?

• Uhh..dehydration? – Nilay Ghosh Apr 1 at 8:17
• @NilayGhosh, but can we draw an electron pushing mechanism? – Shoubhik Raj Maiti Apr 14 at 20:21