Benzene Reacts Via Electrophilic Aromatic Substitution Essay example

823 Words Apr 30th, 2015 4 Pages
Benzene reacts via electrophilic aromatic substitution – discuss the characteristics of this mechanistic pathway. Introduction: First of all what is electrophilic aromatic substitution? It’s a reaction in which an electrophile adds to an aromatic ring by removing the hydrogen atom from the aromatic ring. Therefore the reaction below is known by electrophilic aromatic substitution. Although, the electrophilic aromatic substitution (EAS) is used in the industrial scale synthesis, as it helps in forming new aromatic molecules. As these reactions (EAS) all achieve the same change in molecular structure, some atoms or groups replace the hydrogen atom on an aromatic ring. Therefore it is very much alike to the addition of certain electrophiles to alkenes or alkynes. The first step is electrophilic attack on the pi electrons, to form a carbocation by the help of deprotonation of the arenium ion, as it has a great thermodynamic advantage over nucleophile capture or rearrangement because deprotonation restores aromaticity.

Mechanism of electophilic subistitution reaction for benzene
The electrophilic substitution requires two main steps, firstly by determining a slow rate of reaction which the electrophile forms a sigma-bond to the benzene ring. This then generates a positive charged benzenonium intermediate. Moving to the second step requires a fast reaction this time, where the proton is removed this intermediate state combining to a substituted ring as shown below:…

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