Is the chlorination of methane a free radical halogenation?

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Answer 1 · 2015-06-10T20:34:29

Yes, the chlorination of methane is a free radical reaction.

There are three major steps in the reaction.

Step 1. Initiation

The initiation step involves the homolytic cleavage of a $Cl-Cl$ $"Cl-Cl"$ bond to form two $Cl$ $"Cl"$ atoms.

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Step 2. Propagation

A $C$ $"C"$ atom removes an $H$ $"H"$ from methane, producing $HCl$ $"HCl"$ and a methyl radical.

The newly-formed methyl radical abstracts a $Cl$ $"Cl"$ from a chlorine molecule, producing chloromethane and re-forming a $Cl$ $"Cl"$ atom.

Step 3. Termination

In the termination steps, the radicals combine in all possible combinations.

The termination products are chlorine, chloromethane, and ethane.