Some unconventional pathways in aromatic nitration

This review deals with a group of reaction paths for nitration in homogeneous solution associated particularly with the species NO+, NO2., NO3. and N2O5. Studies on the properties of these and some related nitrogen compounds are considered first. with special reference to the interaction of these species with aromatic compounds. Evidence on the electron transfer mechanism of nitrous acid catalysed nitration, on nitration by nitrogen dioxide in organic solvents, on nitration by preformed dinitrogen pentoxide, and on ozone mediated nitration by nitrogen dioxide is then considered. The emphasis is on the mechanisms of these reactions when carried out using thermal rather than photochemical processes. Some interesting features of these mechanisms are then examined, with particular reference to the oxidation of aromatic substrates by NO3. and possibilities for further work.