Influence of the substituent on the major decomposition channels of the NO2 group in para-substituted nitrobenzenes: a tandem mass spectrometric study
✍ Scribed by T. B. Brill; K. J. James; R. Chawla; G. Nicol; A. Shukla; J. H. Futrell
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 100 KB
- Volume
- 12
- Category
- Article
- ISSN
- 0894-3230
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✦ Synopsis
The relative extents of loss of NO 2 and NO were determined by 70 eV electron ionization and tandem mass spectrometry using B/E linked scans to investigate metastable (unimolecular) and collision-induced dissociation processes for molecular ions formed by electron ionization of para-substituted nitrobenzene compounds. The substituents used (NO 2 , CHO, H, OCH 3 ) represent a wide range of electron donor-acceptor properties. Loss of NO 2 was favored by electron-withdrawing groups, while an electron-donor group favored loss of NO. Ion fragmentation mechanisms are consistent with the hypothesis that NO 2 to ONO (nitro to nitrite) isomerization precedes the loss of NO. Ring fragmentation (loss of CO) was observed only after all of the electron-withdrawing groups had dissociated. while the electron-donor group OCH 3 remained attached to the ring in the analogous CO elimination. These results are placed in the context of the thermolysis behavior of nitroaromatic explosives.