Question

How to convert 2-chlorobutane to 3 4-dimethyl hexane?

Answer 1

Wurtz reaction

• Wurtz reaction is a coupling reaction in organic chemistry.
• In this reaction two alkyl halides are reacted with sodium metal in dry ether solution to form a higher alkane.
• The reaction is given below.

$\mathrm{R}-\mathrm{X}+\mathrm{R}-\mathrm{X}\underset{\mathrm{Dry}\mathrm{ether}}{\overset{\mathrm{Na}}{\to }}\mathrm{R}-\mathrm{R}+2\mathrm{NaX}$

• It can be observed from this equation that the two alkyl groups are joined, yielding an alkane with a longer chain along with$\mathrm{NaX}$, where X is a Halogen.
• Sodium donates electrons to halogens and forms alkyl free radical, which further reacts with halo alkane to form the product.

Conversion of 2-chlorobutane to 3 4-dimethyl hexane

Step 1: Formation of 3 4-dimethyl hexane

One molecule of chlorobutane reacts with sodium and the transfer of an electron from the sodium to the halogen leads to the formation of an alkyl radical along with the metal halide.

Chlorobutane forms free radicals by removal of chlorine.

A different sodium atom now donates a single electron to the butyl radical, leading to the formation of a butane anion.

The carbon belonging to the butyl anion having a nucleophilic nature proceeds to displace the chlorine in Chlorobutane and form a covalent bond with the carbon which was bonded with the Chlorine atom.

The overall reaction is

The product formed in the reaction is 3, 4-dimethyl hexane and Sodium chloride.