RADIATION-INDUCED NITRATION OF BENZENE WITH DINITROGEN TETROXIDE.

The gamma-radiation-induced nitration of benzene with dinitrogen tetroxide N2O4 in the liquid phase at 20C yielded nitrobenzene NB as the major product and the isomerides of dinitrobenzene DNB as the minor products of radiolysis. The yield GNB increased with increasing concentration of N2O4 from 0.14 for 6 mole N2O4 to 1.18 for 95 mole N2O4 in benzene. The ratio of o- to p-DNB is the inverse of that obtained from conventional mixed acid nitration and is considered typical of radiolysis. The nitro-substitution product formations are shown to be from primary processes of radiolysis and are proposed as being derived from an intermediate specie involving an No2.C6H5H pi-donor complex. The NO2 in equilibrium with the N2O4 in the liquid phase is regarded as the nitrating agent in the form of a radical as well as a nitronium ion NO2. Both water and nitrous acid as secondary products of radiolysis are suggested as anti-catalysts inhibiting the degree of the radiation-induced nitration. Author