Question

​An unknown amine is treated with an excess of methyl iodide. Two equivalents of methyl iodide react with amine. The amine is treated with silver oxide and water and then heated to 120 ^oC. The resulting products are trimethylamine and ethylene. Identify the amine.

Answer 1

Dear Student,

The unknown amine reacts with two equivalents of methyl iodide, therefore, the amine is a secondary amine.
A quartenary salt will be formed which on reaction with silver oxide and water gives trimethylamine and ethylene.
Therefore, the reaction taking place would be

$$\begin{gathered} {\mathrm{CH}}_2={\mathrm{CHNHCH}}_3\stackrel{2{\mathrm{CH}}_3\mathrm{I}}{\to }{\mathrm{CH}}_2={\mathrm{CHN}}^{+}({\mathrm{CH}}_3{)}_3\underset{{\mathrm{H}}_2\mathrm{O}}{\overset{{\mathrm{Ag}}_2\mathrm{O}}{\to }}{\mathrm{CH}}_2={\mathrm{CH}}_2+({\mathrm{CH}}_3{)}_3\mathrm{N} \\ \mathrm{Hence},\mathrm{the}\mathrm{amine}\mathrm{is}{\mathrm{CH}}_2={\mathrm{CHNHCH}}_3 \end{gathered}$$