Question

How will you distinguish between primary, secondary, and tertiary amines?

Answer 1

Difference between primary secondary and tertiary amines:

Primary Amines	Secondary Amines	Tertiary Amines
Primary Amines are organic compounds derived from ammonia by the replacement of one Hydrogen atom by organic groups. For example,$\underset{\mathrm{Methyl}\mathrm{amine}}{{\mathrm{CH}}_3{\mathrm{NH}}_2}$	Secondary Amines are organic compounds derived from ammonia by the replacement of two Hydrogen atoms with organic groups. For example,$\underset{\mathrm{DImethyl}\mathrm{amine}}{{\left({\mathrm{CH}}_3\right)}_2{\mathrm{NH}}_2}$	Tertiary Amines are organic compounds derived from ammonia by the replacement of three Hydrogen atoms with organic groups. For example,$\underset{\mathrm{Trimethyl}\mathrm{amine}}{{\left({\mathrm{CH}}_3\right)}_3{\mathrm{NH}}_2}$
On reaction with nitrous acid, it forms primary alcohol$\underset{\mathrm{Ethyl}\mathrm{amine}}{{\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{NH}}_2}+\underset{\mathrm{Nitrous}\mathrm{acid}}{\mathrm{HONO}}\to \underset{\mathrm{Ethanol}}{{\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{OH}}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}}+\underset{\mathrm{Nitrogen}}{{\mathrm{N}}_2}$	On reaction with nitrous acid, yellow coloured, oily N-nitroso amine is formed $\underset{\mathrm{Diethylamine}}{{\left({\mathrm{C}}_2{\mathrm{H}}_5\right)}_2\mathrm{NH}}+\underset{\mathrm{Nitrous}\mathrm{acid}}{\mathrm{HONO}}\to \underset{\mathrm{N}-\mathrm{nitrosodiethylamine}}{{\left({\mathrm{C}}_2{\mathrm{H}}_5\right)}_2\mathrm{N}-\mathrm{N}=\mathrm{O}}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}}$	On reaction with nitrous acid, tertiary Amines give salt which on warming decomposes to give nitrosamines and alcohol $\underset{\mathrm{Trimethylamine}}{{\left({\mathrm{CH}}_3\right)}_3\mathrm{N}}+\underset{\mathrm{Nitrous}\mathrm{acid}}{\mathrm{HONO}}\stackrel{\mathrm{Warm}}{\to }\underset{\mathrm{N}-\mathrm{nitrosodimethylamine}}{{\left({\mathrm{CH}}_3\right)}_2\mathrm{N}-\mathrm{N}=\mathrm{O}}+\underset{\mathrm{Methanol}}{{\mathrm{CH}}_3\mathrm{OH}}$
Primary amines, on reaction with Chloroform and $\mathrm{KOH}$, Carbylamine is produced. $\underset{\mathrm{Ethyl}\mathrm{amine}}{{\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{NH}}_2}+\underset{\mathrm{Chloroform}}{{\mathrm{CHCl}}_3}+\underset{\mathrm{Potassium}\mathrm{hydroxide}}{3\mathrm{KOH}}\to \underset{\mathrm{Ethyl}\mathrm{isocyanide}}{{\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{NC}}+\underset{\mathrm{Potassium}\mathrm{chloride}}{3\mathrm{KCl}}+\underset{\mathrm{Hydrogen}}{3{\mathrm{H}}_2}$	Secondary amines give no reaction with Chloroform and $\mathrm{KOH}$	Tertiary amines give no reaction with Chloroform and $\mathrm{KOH}$
Primary amines on reaction with Acetyl chloride, N-alkyl acetamide is formed.	Secondary amines on reaction with Acetyl chloride, N, N-dialkyl acetamide is formed.	Tertiary amines give no reaction with Acetyl chloride.
Primary amines on reaction with ${\mathrm{CS}}_2$ and $\mathrm{HgCl}$, Alkyl isothiocyanate is formed.	Secondary amines gives no reaction with ${\mathrm{CS}}_2$ and $\mathrm{HgCl}$.	Tertiary amines give no reaction with ${\mathrm{CS}}_2$ and $\mathrm{HgCl}$