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Six positional isomers are possible for dinitrotoluene. The most common one is 2,4-dinitrotoluene. The nitration of toluene gives sequentially mononitrotoluene, DNT, and finally TNT. 2,4-DNT is the principal product from dinitration, the other main product being about 30% 1,3-DN2-T.
Together with other isomers, 4-nitrotoluene is prepared by nitration of toluene, [4] commonly using titanium(IV) nitrate. [5] It undergoes the reactions typical for nitrobenzene derivatives, e.g. hydrogenation gives p-toluidine. Oxidation of the methyl substituent of 4-nitrotoluene has been extensively investigated.
The phrase ipso nitration was first used by Perrin and Skinner in 1971, in an investigation into chloroanisole nitration. [18] In one protocol, 4-chloro- n -butylbenzene is reacted with sodium nitrite in t -butanol in the presence of 0.5 mol% Pd 2 (dba) 3 , a biarylphosphine ligand and a phase-transfer catalyst to provide 4-nitro- n -butylbenzene.
Although discussions of directing groups usually focus on electronic effects (e.g. EWG vs EDGs), steric effect can prove influential. Thus, nitration of toluene gives approximately 2:1 ortho vs para-nitrotoluene. In the case of tert-butylbenzene, however, the selectivity is reversed:73% of the product is 4-nitro-tert-butybenzene]]. [4]
o-Toluidine is produced industrially by nitration of toluene to give a mixture of nitrotoluenes, favoring the ortho isomer.This mixture is separated by distillation. 2-Nitrotoluene is hydrogenated to give o-toluidine.
They can be viewed as nitro derivatives of toluene or as methylated derivatives of nitrobenzene. Mononitrotoluene comes in four isomers, differing by the relative position of the methyl and nitro groups. All are pale yellow with faint fragrances: ortho-nitrotoluene (also called ONT, o-nitrotoluene, or 2-nitrotoluene). m.p. = -10.4 °C
It is made by nitrating toluene by conventional mixed acid (acetyl nitrate doesn't produce it [4]): this reaction mainly affords a 2:1 mixture of 2-nitro and 4-nitro isomers, but after removal of the 2-isomer, the 3-nitrotoluene can be purified by distillation.
It is made by nitrating toluene at above -10 °C. This reaction affords a 2:1 mixture of 2-nitro and 4-nitro isomers. [4] Chlorination of 2-nitrotoluene gives two isomers of the chloronitrotoluenes. Similarly nitration gives two isomers of dinitrotoluene. 2-Nitrotoluene is mainly consumed in the production of o-toluidine, a precursor to dyes. [4]