Nitration of Benzene

=> Substitution reaction not addition as addition would de-stablise benzene.
There are two steps to the process: Addition and elimination.

Addition

Electrophile E+ is attracted to the delocalised electron cloud.
A co-ordinate bond forms between one of the carbon atoms in the benzene ring and the electrophile.
An unstable positively charged intermediate is formed.

Elimination

C-H bond breaks
Its pair of shared electrons restores the stable delocalised electron structure.
A hydrogen ion is eliminated.

Nitration
=> Nitro group
=> When NO2 is substituted into benzene in place of one of the hydrogens.
=> Benzene becomes the yellow oil liquid.
=> C6H6 + HNO3 ---> C6H5NO2 +H2O
=> C6H6 + NO2+ ---> C6H5NO2 + H+
=> We make the nitronium ion by using the nitrating mixture.
=> This consists of concentrated nitric acid and concentrated sulphuric acid.

Reaction to produce nitrobenzene:
=> 50 degrees celsius
=> Nitrating mixture of concentrated sulphuric acid and concentrated nitric acid.
=> Reagents: Benzene and nitric acid (concentrated)
=> The catalyst is considered to be concentrated sulphuric acid as it is reformed at the end.

Halogenation of benzene

Works with AlCl3, FeCl3, AlBr3, and FeBr3
To make mix halogen with metal.
Halogen carrier acts as the catalyst.
Example overall equation: H+ + FeBr4- ---> FeBr3 and HBr