From meta-brombenzoicacid two nitrobrombenzoic ac i ds are obtained on direct nitration; elimination of the bromine atom and the reduction of the nitro to an amino group in these two acids results in the formation of the same ortho-aminobenzoic acid.
This substance readily yields ortho-oxybenzoic acid or salicylic acid, which on nitration yields two mononitro-oxybenzoic acids.
Direct nitration gives (principally) m-nitrobenzoic acid, also pseudotetragonal with a much shorter principal axis.
The reaction is generally carried out in the presence of sulphuric acid, which is used to absorb the water formed during the process of nitration.
Three isomers exist, the orthoand para-compounds being the chief products of the direct nitration of toluene.
