monochlorination of ethane

• Ethane + chlorine = chloroethane + hydrogen chloride

  C2H6 + Cl2 = C2H5Cl + HCL
• initiation

  Cl2 = Cl* + Cl*

  in presence of uv light
• propagation 


  C2H6 + Cl* = C2H5* + HCl

  C2H5 + Cl2 = C2H5Cl + Cl *

  Chlorine radical formed at the end of the last equation is now free to react with another ethane. This is called a “chain reaction” ​
• termination


  Cl*   +    Cl*     =    Cl2​

  C2H5* +   Cl*        =    C2H5Cl​

  C2H5* +   C2H5*   =    C4H10 
• proof of mechanism

  formation of butane when ethane is used suggests ethyl radical production

  If irradiation stops (UV) the reaction stops

  addition of radical promoters (tetra-ethyl lead) speeds up the rate of reaction