Class 12 Chemistry Haloalkanes and Haloarenes Conditions of E1 reaction

Conditions of E1 reaction:

The factors that favors SN1 reaction also favors E1 reaction which are as follows:

Alkyl halide:

E1 reaction occurs faster if the carbocation intermediate is more stable and has a lower activation barrier.

3̊ carbocation > 2̊ carbocation > 1̊ carbocation.

Leaving group:

The leaving group with a full negative charge is always expelled out. As a result the best leaving groups are those that can best stabilize an anion. In this reaction, it will not be odd to consider water as a leaving group.


When a carbocation undergoes solvation it allows the carbocation to get surrounded by more electron density thereby making the +ve charge more stable. The solvent can be protic or Aprotic but it must be polar. 



Those nucleophiles that undergo E1 mechanism are weak neutral molecules. Any nucleophiles stronger than this is also a strong base that results in elimination reactions.  

Like the E2 reaction, the E1 favors the Zaitsev product (always).

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