Question

How will you obtain Ethylamine from the following? Write chemical equation only:
(i) Methyl cyanide
(ii) Propanamide
(iii) Acetamide
(iv) Nitroethane
(v) Ethyl isocyanate

Hint:

Nitrile reduction and amide (LAH) reduction preserve the carbon count; Hofmann bromamide shortens the chain by one carbon; nitro \(\Rightarrow\) amine by reduction; isocyanate \(\Rightarrow\) amine by hydrolysis with loss of CO\(_2\).

Answer 1

(i) From methyl cyanide (acetonitrile)
\[ \mathrm{CH_3CN} + 2\,\mathrm{H_2} \xrightarrow[\ \Delta\ ]{\mathrm{Ni}} \mathrm{CH_3CH_2NH_2} \text{(reduction of nitrile)} \] (ii) From propanamide (Hofmann bromamide)
\[ \mathrm{CH_3CH_2CONH_2} + \mathrm{Br_2} + 4\,\mathrm{NaOH} \rightarrow \mathrm{CH_3CH_2NH_2} + 2\,\mathrm{NaBr} + \mathrm{Na_2CO_3} + 2\,\mathrm{H_2O} \] (iii) From acetamide (LAH reduction)
\[ \mathrm{CH_3CONH_2} \xrightarrow[\mathrm{H_3O^+}]{\mathrm{LiAlH_4}/\text{ether}} \mathrm{CH_3CH_2NH_2} \] (iv) From nitroethane
\[ \mathrm{CH_3CH_2NO_2} + 3\,\mathrm{H_2} \xrightarrow{\mathrm{Ni}} \mathrm{CH_3CH_2NH_2} + 2\,\mathrm{H_2O} (\text{or } \mathrm{Fe/HCl}) \] (v) From ethyl isocyanate (hydrolysis)
\[ \mathrm{CH_3CH_2NCO} + \mathrm{H_2O} \xrightarrow{\Delta} \mathrm{CH_3CH_2NH_2} + \mathrm{CO_2} \]