REACTION MECHANISM
Radical halogenations take place in three stages called: initiation, propagation and termination:
Initiation stage
In the first step of the reaction, the homolytic cleavage of the Cl-Cl bond occurs. This is achieved with heat or by absorbing light.
First stage of propagation
It is a slightly endothermic stage that consists of the subtraction of a hydrogen from methane by the chlorine radical formed in the previous stage, generating the methyl radical.
Second stage of propagation
During it, the methyl radical abstracts a chlorine atom from one of the initial molecules, giving chloromethane and a new chlorine atom. Said atom returns to the first stage of propagation and the whole process is repeated.
Termination stage
It takes place when the reagents are exhausted, then the radicals that are in the middle unite with each other.
