Q27E - Organic Chemistry (Mcmurry)

Question

Draw the electron-pushing mechanism for each radical reaction below. Identify each step as initiation, propagation, or termination.

(a) 

b) 

c) 

Step-by-Step Solution

Answer

a. 

b. 

c. 

Step 1: Free radical reaction

The reaction which involves free radicals is called a free radical reaction.

The free radical reaction is completed in three-step. The first step of the reaction is an initiation then the second step is propagation and the third step is termination. 

Step 2: Mechanism of reaction free radical reaction

Initiation Step:

Radical reactions are initiated by light. The reaction is also initiated by UV light. In the first step$\text{Cl-Cl}$ bond break, homolytically and $\text{Cl}$ free radical is formed. Also, cyclopentane and hydrogen-free radicals form by breaking the $\text{C-H}$ bond of the cyclopentane ring.

Propagation step:

In this step, the radicals which are generated in the initiation step collide with each other and new radicals are generated.

Termination step:

When two free radicals collide with each other then the chain is terminated.

Step 3: Free radical reactions

a. 

mechanism

Mechanism of Reaction a

b. 

mechanism

c.

mechanism

Mechanism of Reaction c