Chlorination Of Alkanes Flashcards
What is free radical substitution?
Alkanes can undergo free radical substitution in which a hydrogen atom get substituted by a halogen (chlorine/bromine)
What is needed for free radical solution to occur?
Alkanes are very unreactive UV light (sunlight) is needed for this substitution reaction to occur
What are the three steps to the three radical substitution?
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
Describe the initiation step
-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 )
What is a homolytic fission reaction?
Where each atom gets one electron from the covalent
Describe the propagation step
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
Describe the propagation step
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
For how long does propagation continue?
Until full substitution has occurred
Describe the termination
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
