The bromination of benzene in presence of FeBr is an example ofa)elect...
Electrophilic Substitution: Bromination of Benzene
Electrophilic substitution is a type of organic reaction in which an electrophile replaces a functional group or atom in a molecule. The bromination of benzene in the presence of FeBr is an example of electrophilic substitution.
Mechanism of Electrophilic Substitution
1. Generation of Electrophile
In the bromination of benzene, an electrophile is generated by the reaction between bromine and iron (III) bromide. The electrophile generated is Br+.
Br2 + FeBr3 → Br+ + FeBr4-
2. Formation of Sigma Complex
The electrophile Br+ then forms a sigma complex with the benzene ring. The pi electrons of the benzene ring are attracted towards the electrophile and form a bond with the Br+ ion.
3. Rearrangement of Sigma Complex
The sigma complex then undergoes a rearrangement in which the carbon-carbon single bonds are broken, and the pi electrons are rearranged. This rearrangement leads to the formation of a new intermediate called arenium ion.
4. Loss of Proton
The arenium ion then loses a proton to form the final product, which is bromobenzene.
Overall Reaction
The overall reaction for the bromination of benzene is as follows:
C6H6 + Br2 → FeBr3/Br2 C6H5Br + HBr
Conclusion
The bromination of benzene is an example of electrophilic substitution, in which an electrophile replaces a hydrogen atom on the benzene ring. This reaction is important in organic chemistry as it is a key step in the synthesis of many important organic compounds.
The bromination of benzene in presence of FeBr is an example ofa)elect...
Electrophilic Substitution in Bromination of Benzene
The bromination of benzene in the presence of FeBr3 is an example of electrophilic substitution.
Electrophilic substitution is a type of organic reaction in which an electrophile replaces a functional group in a molecule. In the bromination of benzene, an electrophile (FeBr3) is added to the benzene ring. This creates a positively charged intermediate, which is then attacked by a negatively charged bromide ion. The final product is bromobenzene.
Mechanism of Electrophilic Substitution
1. Formation of a Complex
FeBr3 acts as a Lewis acid and forms a complex with the bromine molecule. This complex is a stronger electrophile than the bromine molecule alone.
2. Generation of a Positive Charge
The complex formed between FeBr3 and the bromine molecule is then attacked by a lone pair of electrons on the benzene ring. This results in the formation of a positively charged intermediate.
3. Attack by a Nucleophile
The positively charged intermediate is attacked by a negatively charged bromide ion. This results in the formation of the final product, bromobenzene.
Overall Reaction
The overall reaction for the bromination of benzene is as follows:
C6H6 + Br2 → FeBr3 C6H5Br + HBr
Conclusion
The bromination of benzene in the presence of FeBr3 is an example of electrophilic substitution. This reaction involves the formation of a complex, the generation of a positive charge, and the attack by a nucleophile. The final product is bromobenzene.
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