As I have a solution of R-NH2 and another solution of HOOC-R*-COOH. I want to know if I can bind them together without any cross-linker or catalizer but only stirring them overnight at room temperature?
Are COOH and NH2 attracted naturally to each other to form R-NH-CO-R*-COOH ???
R-NH2 & HOO-C-RCOOH will react as the equation shows:
R-NH2 + HOO-C-RCOOH → R-NH3+-OOC-R-COO-+H3N-R
The reaction is between a weak base & a weak acid so the product will be a diammonium salt of the dicarboxylic acid. If one wants to get a diamide, then : i) The salt is recrystallized. ii) The salt is heated carefully to dehydrate it into R-NH-CO-R-CO-NH-R . iii) The colored diamide is purified by washing or better by recrystallization.
Yes it is possible in 1:1 equimolar ratio. it is better if you use some solvent media, like ethyl acetate,etc.
Amide-coupling reactions between (aliphatic) carbonic acids and (aliphatic) alkylamines demands for an "activated" carboxylic function, in order to be successful. As Dr. Matar outlined in his answer, the competing acid-base reaction of the components to produce the salt will interfere with the coupling otherwise.
An advice is to use the acid chloride as an activated form, which is easily accesible from the parent acid via reaction in neat SOCl2 (R-COOH + SOCl2 --> R-COCl + SO2 + HCl).
Best wishes
The reaction occurs only in the presence of catalyst - mineral acids
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