Primary, secondary, tertiary amines can be separated by the following except:
- Fractional distillation
- Fractional method using diethyl oxalate
- Hinsberg's method using \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{SO}_{2} \mathrm{Cl}\)
- Selective crystallisation
Solution
\(1^{\circ}, 2^{\circ}\) and \(3^{\circ}\) amines \(+\mathrm{R}_{4} \mathrm{N} \mathrm{X} \stackrel{\text { distillation }}{\longrightarrow}\) Mixture
Mixture of \(1^{\circ}, 2^{\circ}, 3^{\circ}\) amine can be separated by following methods.
(i) Fractional distillation: The mixture of amines may be fractional distillation because their boiling points are quite different. It is used in industry.
(ii) Hinsberg method: In this method mixture of amines is seperated by using benzene sulphonyl chloride (Hinsberg's reagent).
\(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{SO}_{2} \mathrm{Cl}+1^{\circ}\) amine \(ightarrow\) Product \(\stackrel{\text { KOH }}{\longrightarrow}\) dissolve
\(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{SO}_{2} \mathrm{Cl}+2^{\circ}\) amine \(ightarrow\) Product \(\stackrel{\text { KOH }}{\longrightarrow}\) insoluble
\(3^{\circ}\) amine does not react with benzene sulphonyl chloride.
(iii) Hofman method: In this method mixture of amines is separated by using ethyl oxalate.
\(1^{\circ}\) amine \(+\) ethyl oxalate \(ightarrow\) solid product
\(2^{\circ}\) amine \(+\) ethyl oxalate \(ightarrow\) liquid product
\(3^{\circ}\) amine + ethyl oxalate \(ightarrow\) No reaction
Asked in: JEE-TOPICTESTS-CHEMISTRY