Organic Reactions - Free Radical

Description:

Involve the addition of a radical across an organic molecule.

For example, addition of a halogen across a double bond follows free-radical mechanism.

Due to their high reactivity, these are non-selective in nature.

There are 3 stages of free radical reaction. Let’s take an example of free radical halogenation of ethane.

• Initiation − Halogens in the presence of heat or UV-radiation undergoes homolytic fission giving free radicals.

  

• Propagation − The bromine radical attacks ethane by breaking the C - H bonds and generates ethyl free radical. The ethyl radical further attacks another bromine molecule regenerating the bromine radical.

  

  The reaction is non-selective and results in parallel propagation steps such as −

  

• Termination − The reaction terminates when the reactant molecules are completely consumed or due to the following side reactions.