Chlorination Of Alkanes

Alkanes can undergo free radical substitution in which a hydrogen atom get substituted by a halogen (chlorine/bromine)

Alkanes are very unreactive UV light (sunlight) is needed for this substitution reaction to occur

Initiation= the halogen bond (Cl-Cl or Br-Br) is broken by UV energy to form 2 free radicals Propagation = these radicals create further radicals in a chain reaction Termination = these reason is terminated when two radicals collide with each other

-First step - cl-cl or br-br is broken by energy from the uv light - each atom one electron from the covalent bond -produces two radicals in a homolytic fission reaction ( see equation in notes )

Where each atom gets one electron from the covalent

Second step Refers to the progression (growing) of the substitution reaction in a chain reaction Free radicals are very reactive and will attack the unreactive alkanes A c-h bond breaks homolytically An alkyl free radicals is produced

Second step Refers to the progression (growing) of the substitution reaction in a chain reaction Free radicals are very reactive and will attack the unreactive alkanes A c-h bond breaks homolytically An alkyl free radicals is produced

Until full substitution has occurred

Final step When the chain reaction terminates due to 2 free radicals reacting together and forming a single a single unreactive molecule Two radicals-> one product Multiple products are possible dependent on radicals involved