51E - Organic Chemistry (Mcmurry)

Question

1,6 Hexanediamine, a starting material needed for making nylon, can be made from 1,3 butadiene. How would you accomplish the synthesis?

 ${\mathbf{H}}_{\mathbf{2}}\mathbf{C}\mathbf{=}\mathbf{CHCH}\mathbf{=}{\mathbf{CH}}_{\mathbf{2}}\stackrel{\mathbf{?}}{\mathbf{\to }}{\mathbf{H}}_{\mathbf{2}}{\mathbf{NCH}}_{\mathbf{2}}{\mathbf{CH}}_{\mathbf{2}}{\mathbf{CH}}_{\mathbf{2}}{\mathbf{CH}}_{\mathbf{2}}{\mathbf{CH}}_{\mathbf{2}}{\mathbf{CH}}_{\mathbf{2}}{\mathbf{CH}}_{\mathbf{2}}{\mathbf{NH}}_{\mathbf{2}}$

Step-by-Step Solution

Answer

1,6-Hexanediamine can be synthesized from 1,3-butadiene through the steps 

Step 1: Definition of synthesis

The construction of complex chemical compounds from simpler ones is defined as synthesis.

Step 2: Explanations

1,3 butadiene is a conjugated diene. Hence it is treated with bromine, and a 1,4-addition of bromine to the diene takes place to yield 1,4-dibromobut-2-ene. Treatment with NaCN converts the dibromide to 1,4-dicyanobut-2-ene. When treated with LiAlH₄ the nitrile groups are reduced to $-{\mathrm{CH}}_2{\mathrm{NH}}_2$ groups to give 1,6-dicyanohex-3-ene. The double bond is not reduced by LiAlH₄. It is reduced by treating with H₂,Pd/C to get 1,6-hexane diamine.

1,6-Hexanediamine can be synthesized from 1,3-butadiene through the steps