Nitrobenzene mass spectrum

The thermochemical reactivity of nitrobenzene is remarkably parallel to its mass spectrum. In a mass spectrometer, nitrobenzene fragments by loss of the NO 2 and also by rearrangement to 43 which gives oxygen containing fragment ions (Eq. (30)). ) The primary products from thermolysis... 

Aromatic nitro compounds show intense molecular ion peaks. The characteristic NO (mie = 30) and mJe = 46) peaks appear in the mass spectrum. The principal fragmentation pattern, however, involves loss of all or part of the nitro group. Using nitrobenzene (Fig. 8.46) as an example, this fragmentation pattern may be described as follows. 

III) The mass spectrum of the organic compounds benzene (CsHs), nitrobenzene (C6H5NO2) and phenol (CsHsOH) all contain an intense peak at m/e = 77 - why ... 

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