Nitration in inert fluids

Abstract

Nitration in Inert Fluids Traditional methods of nitration have several disadvantages including the environmental problem of disposal of the spent acid. A main aim of this work was to investigate alternative methods for nitration while minimising the amount of acid required. Perfluorocompounds have been used as bulking agents to replace partially the acid solvent. They are chemically inert and may be reused without the need for purification. Mechanistic and synthetic studies of nitration reactions have been made. Toluene was successfully nitrated to trinitrotoluene using less sulfuric acid than in traditional methods. Benzene, styrene and trans-stilbene have been nitrated using nitric acid or dinitrogen pentoxide in perfluorocompounds. Kinetic results have been obtained for the homogeneous nitrations by N(_2)O(_5) in perfluorodecalin of substrates including 4-chloroanisole, 4-bromophenetole, 4- bromophenol and various chlorophenols. The rate constants have been determined and some mechanistic conclusions have been made. The nitration of various amines using dinitrogen pentoxide or nitric acid in perfluorocarbons has been studied. Nitrated derivatives of morpholine, pyrrolidine, piperidine, oxazolidinone and pyrimidine were successfully obtained using N-(^t)butoxycarbonyl, acetyl or silyl amines.