Question

The following reaction is known to proceed by a free radical chain mechanism. Suggest a reasonable, step-by-step mechanism for this reaction.

CH3CHCH2 + CHCl3 CH3CH2CH2CCl3

Answer 1

The given reaction CH3CHCH2 + CHCl3 -> CH3CH2CH2CCl3 proceeds through a free radical chain mechanism. The reaction involves initiation, propagation, and termination steps. The initiation step involves breaking the Cl-Cl bond in CHCl3, while the propagation step consists of the reaction between chlorine radicals and CH3CHCH2 to form the desired product. The termination step occurs when free radicals react with each other to terminate the reaction chain.

Step-by-step explanation:

The given reaction CH3CHCH2 + CHCl3 -> CH3CH2CH2CCl3 proceeds through a free radical chain mechanism. Here is a step-by-step mechanism for this reaction:

1. Initiation: The reaction is initiated by breaking the Cl-Cl bond in CHCl3 through the absorption of UV light or heat. This produces two chlorine radicals (Cl•).
2. Propagation: One chlorine radical (Cl•) attacks the CH3CHCH2 molecule, abstracting a hydrogen atom and forming a CH3CHCH2• radical. The chlorine radical (Cl•) then reacts with hydrogen in the presence of UV light or heat, forming HCl. The final product is CH3CH2CH2CCl3.
3. Termination: Two free radicals can react with each other to terminate the chain. For example, the CH3CHCH2• radical can react with a chlorine radical (Cl•), forming CH3CHCH2Cl.