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[reaction: see text] TATP gives rise to two separable conformations because the barrier for interconversion between them is relatively high at room temperature. This kind of behavior is rare in cyclic organic systems and is the result of poor overlap in the "flip-flop" transition state. The crystal structure of the analogous tricyclohexanone triperoxide also indicates the presence of two conformers. 相似文献
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Tsippy Tamiri Rinat Rozin Nitay Lemberger Joseph Almog 《Analytical and bioanalytical chemistry》2009,395(2):421-428
Urea nitrate is a powerful improvised explosive, frequently used by terrorists in the Israeli arena. It was also used in the
first World Trade Center bombing in New York in February 1993. It is difficult to identify urea nitrate in post-explosion
debris, since only a very small fraction survives the blast. Also, in the presence of water, it readily decomposes to its
original components, urea and nitric acid. It is suspected that post-blast debris of urea nitrate can be confused with ammonium
nitrate, the main solid product of urea nitrate thermal decomposition. In a comprehensive study towards identification of
urea nitrate in post-blast traces, a spectrophotometric technique for quantitative determination of urea nitrate was developed,
and conditions were found for extraction and separation of un-exploded traces of urea nitrate with minimal decomposition.
Nevertheless, out of 28 samples collected from a series of three controlled firings of urea nitrate charges, only one gave
the typical adduct ion by liquid chromatography/mass spectrometry analysis. We found that urea nitrate can be extracted from
solid mixtures to organic solvents by using Crown ethers as “host compounds.” The adducts thus formed are solid, crystalline
compounds that can be characterized by microanalysis and spectroscopic techniques.
Figure Adduct formation between urea nitrate and 18-crown-6 相似文献
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I. Vidavsky A. Mandelbaum T. Tamiri S. Zitrin 《Journal of mass spectrometry : JMS》1991,26(4):287-292
Isomeric mixed dialkyl phenylsuccinates, PhCH(COOR)CH2COOR′, undergo a highly specific elimination of ROH under electron impact. A deuterium-labelling study showed that the hydrogen atom from the benzylic position 2 is abstracted in this process. These results suggest the occurrence of a ‘hidden’ hydrogen migration of the benzylic hydrogen atom to the carbonylic oxygen of the remote ester group, followed by the elimination of ROH from the adjacent ester group with the involvement of that hydrogen. Alkoxyl group migrations resulting in the formation of [PhCH?OR]+ and [PhCH?OR′]+ ions are less specific, although the migration of the remote R′O˙ is significantly preferred in all the pairs of isomers examined. Mechanisms are suggested for the formation of the two ions. 相似文献
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Urea nitrate (UN) and nitrourea (NU), easily prepared from urea and nitric acid, convert deactivated aromatic compounds to the corresponding nitrated derivatives with a high yield and a high regioselectivity under very mild conditions. The performance of the two reagents is quite similar indicating that NU is an intermediate in the UN nitration process. 相似文献
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Tamiri T 《Rapid communications in mass spectrometry : RCM》2005,19(14):2094-2098
Mass spectra of urea nitrate were measured in electrospray ionization and in atmospheric pressure chemical ionization in the negative mode. In both ionization methods two characteristic adduct ions containing the intact molecule [urea nitrate+NO3]- and [urea nitrate+HNO3+NO3]- are shown. The structure of the two adduct ions was deduced using measurements of isotopically labeled urea nitrate. Collision-induced dissociation measurements of the adduct ions show typical losses enabling the identification of urea nitrate in trace amounts. Using these methods urea nitrate was identified in real cases. 相似文献
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