Ammonolysis involves the nucleophilic attack of ammonia on an alkyl halide. $N{H}_3+R-X\to R-N{H}_2+HX$

• However, the resulting primary amine ($R-N{H}_2$) is itself a nucleophile and is more reactive than ammonia. It continues to react with remaining alkyl halide:
• $R-N{H}_2+R-X\to R_{2}NH$
• $R_{2}NH+R-X\to R_{3}N$
• $R_{3}N+R-X\to [R_{4}N{]}^{+}{X}^{-}$ (Quaternary ammonium salt)
• This 'over-alkylation' leads to a mixture of products, making this a poor method for preparing pure primary amines unless a massive excess of ammonia is used.