HIGH-VACUUM PYROLYSIS STUDIES OF PRIMARY STAGES OF THERMAL-DECOMPOSITION OF NITROBENZENES

High-vacuum pyrolysis studies of the primary stages of monomolecular t hermal decomposition (TD) of o- and p-dinitrobenzenes and iodonitroben zenes are carried out by mass-spectrometric analysis. Primary TD produ cts are reliably established from the data on the nature of electron i mpact (EI)-induced fragmentation of these compounds. The mechanisms of this process are shown to basically differ for the compounds under st udy. The first stage in thermal destruction of p-dinitrobenzene and p- iodonitrobenzene is a nitro-nitrite rearrangement. The decomposition o f o-iodonitrobenzene occurs by a radical mechanism with C-N bond cleav age, while in the case of o-dinitrobenzene, it begins with the formati on of a cyclic activated complex followed by the splitting off of thre e oxygen atoms.