Acetylation of amines : The reaction in which the H atom attached to nitrogen in amine is replaced by acetyl group 
is called acetylation of amines.
(1) Ethylamine on reaction with acetic anhydride forms monoacetyl derivative, Nacetylethylamine.
(2) Diethylamine (a secondary amine) on reaction with acetic anhydride forms a monoacetyl derivative, N-acetyldiethyl amine (or N,N-diethyl acetamide).
(3) Triethylamine does not react with acetic anhydride as it does not have any H atom attached nitrogen atom of amin e
