Nitration with nitric acid alone or in mixture with acetic anhydride, acetic acid or sulfuric acid, are normal examples of including nitro functional groups to aromatic hydrocarbons. Aliphatic (i.e, straight or branched chain hydrocarbon) nitration is less common compared to aromatic, however propane could be nitrated under pressure in order to yield nitropropanes.
The nitro group is an extremely strong deactivating group, i.e, when put into a benzene ring, the ring gets less reactive. This deactivation outcomes from the very powerful electron-withdrawing property from the nitro group. Nitrobenzene, for instance, goes through nitration at a rate which is one-ten-thousandth the rate showed by benzene. In nitrated alkanes (nitroalkanes), according to the location of the hydrogen atom within the molecule, a hydrogen ion may be made by the reaction of the nitroalkane with a solid base, due to the powerful electron-withdrawal outcomes of an adjacent nitro group.
The reduction of nitro groups to nitroso groups is tough, because the latter is instantly reduced more to substituted hydroxylamines and amino groups. Only by picking reaction circumstances judiciously can the reduction be ceased at the nitroso stage. In an alternative approach, the reduction is permitted to proceed to some hydroxylamine which subsequently is oxidized with dichromate for the nitroso derivative.
The initial step consists of protonating the nitro group followed through reduction to a derivative with three-valent nitrogen. Protonation and lack of water yield the nitroso compound. Usually, the nitroso compound is further decreased rapidly and cannot be isolated throughout the reduction in acidic solution. However, reduction of aromatic nitro compounds within alkaline solution give rise to competing reactions that significantly decelerate further reduction. Under these circumstances the nitroso compounds could be isolated.
Reduction Of Nitro Group Mechanism: The nitro group in aromatic nitro compounds made up of reducible substituents for example carboxylic acids, methyl and phenols and halogens are selectively and quickly reduced at room temperature to the related amines in great yield by utilizing hydrazine glyoxylate in the existence of magnesium powder or zinc powder.It has been observed that hydrazine glyoxylate is more successful than glyoxylic acid, hdrazine, ammoniuin monoformate or hydrazinium monoformate and reduction of the nitro group takes place without hydrogenolysis in the existence of low-cost magnesium than expensive metals such as platinum, palladium, ruthenium and so on. The products have been characterized through comparison of their TLC, infrared spectra and melting points.