Mechanism of chlorination of methane involves three types.
Step 1: Initiation: Chlorine absorbs energy and undergoes homolysis to give chlorine-free radicals.
Step 2: Propagation: Chlorine free radical reacts with methane to give methyl free radical.
Cl• + CH4 → CH3• + HCl
The methyl free radical reacts with chlorine to form methyl chloride and chlorine-free radical.
CH3• + Cl2 → CH3Cl + Cl•
Step 3: Termination: Free radicals combine to form stable products.
Cl• + Cl• → Cl (Chlorine)
CH3• + CH3•→ C2H6 (Ethane)
CH3• + Cl• → CH3Cl (Methyl Chloride)