Question

An aliphatic amine has a molecular mass of 59. Draw all its possible isomers.

Answer 1

An aliphatic amine has a molecular mass of 59.

First, we need to derive the molecular formula for aliphatic amine.

The molecular formula of aliphatic amine is ${ C }_{ n }{ H }_{ 2n+1 }{ NH }_{ 2 } or { C }_{ n }{ H }_{ 2n+3 }N.$

As it is given that the molecular mass of aliphatic amine is 59.

So, 12n + 2n + 3 + 14 = 59

$n\quad =\quad \frac { 59\quad -\quad 17 }{ 14 } \quad =\quad \frac { 42 }{ 14 } \quad =\quad 3$

Substitute n = 3 in the molecular formula and we get,

${ C }_{ 3 }{ H }_{ 9 }N$

The possible isomers are:

(i)        $C{ H }_{ 3 }\quad -\quad C{ H }_{ 2 }\quad -\quad C{ H }_{ 2 }\quad -\quad { NH }_{ 2 }$ - This is 1-amino propane

(ii)        $C{ H }_{ 3 }\quad -\quad CH\quad -\quad { NH }_{ 2 }\\ \quad \quad \quad \quad \quad \quad \quad |\\ \quad \quad \quad \quad \quad \quad C{ H }_{ 3 }$ - This is 2-amino propane

(iii)        $C{ H }_{ 3 }\quad -\quad C{ H }_{ 2 }NHC{ H }_{ 3 }$ - This is methylethylamine

(iv)        $C{ H }_{ 3 }\quad -\quad N\quad -\quad C{ H }_{ 3 }\\ \quad \quad \quad \quad \quad \quad |\\ \quad \quad \quad \quad \quad \quad C{ H }_{ 3 }$ - This is trimethylamine