First of all, an elimination reaction is a type of organic reaction in which two substituents are removed from a molecule in either a one or two-step mechanism.
- The one-step mechanism is known as the E2 reaction
- The two-step mechanism is known as the E1 reaction.
Note: The numbers do not have to do with the number of steps in the mechanism, but rather the kinetics of the reaction, bimolecular and unimolecular respectively.
What is E2 mechanism?
E2 is the first step of elimination with a single transition state .
Typically undergone by primary substituted alkyl halides, but is possible with some secondary alkyl halides.
- The reaction rate is second order.
- E2 typically uses a strong base, it needs a chemical strong enough to pull off a weakly acidic hydrogen.
- E2 competes with the SN2 reaction mechanism.