The preparation of 2,4,6-trinitrotoluene TNT from toluene and nitric acid involves a series of nitration reactions. The overall process can be divided into three main steps, each involving the addition of a nitro group -NO2 to the toluene molecule. The reaction mechanism for each step is electrophilic aromatic substitution.1. First Nitration Mono-nitration :Toluene C6H5CH3 reacts with a mixture of concentrated nitric acid HNO3 and concentrated sulfuric acid H2SO4 to form 2-nitrotoluene and 4-nitrotoluene as major products. The concentrated sulfuric acid acts as a catalyst and helps in the formation of the nitronium ion NO2+ , which is the electrophile in this reaction.Reaction conditions: Temperature around 0-30C, and a mixture of concentrated HNO3 and H2SO4 1:1 ratio .Mechanism:a Formation of nitronium ion NO2+ : HNO3 + 2H2SO4 NO2+ + H3O+ + 2HSO4-b Electrophilic attack: The nitronium ion NO2+ attacks the aromatic ring of toluene, forming a resonance-stabilized carbocation.c Deprotonation: A proton from the carbocation is removed by the HSO4- ion, regenerating the aromatic ring and forming the nitrotoluene product.2. Second Nitration Di-nitration :The mono-nitrotoluene product either 2-nitrotoluene or 4-nitrotoluene is further nitrated using a mixture of concentrated nitric acid and concentrated sulfuric acid to form dinitrotoluene isomers.Reaction conditions: Temperature around 30-50C, and a mixture of concentrated HNO3 and H2SO4 1:1 ratio .The mechanism for this step is similar to the first nitration, with the nitronium ion attacking the mono-nitrotoluene molecule and forming a resonance-stabilized carbocation, followed by deprotonation to form the dinitrotoluene product.3. Third Nitration Tri-nitration :The dinitrotoluene isomer 2,4-dinitrotoluene is further nitrated using a mixture of concentrated nitric acid and concentrated sulfuric acid to form 2,4,6-trinitrotoluene TNT .Reaction conditions: Temperature around 60-80C, and a mixture of concentrated HNO3 and H2SO4 1:1 ratio .The mechanism for this step is also similar to the previous nitration steps, with the nitronium ion attacking the dinitrotoluene molecule and forming a resonance-stabilized carbocation, followed by deprotonation to form the TNT product.In summary, the preparation of 2,4,6-trinitrotoluene TNT from toluene and nitric acid involves three nitration steps, each with electrophilic aromatic substitution as the reaction mechanism. The conditions for each step involve increasing temperatures and a mixture of concentrated nitric acid and sulfuric acid.