From polynitro compounds

Energedcdlly rich polynitro compounds hjve been prepared from polycyclic kelones by the nitro compounds, as shown In Table 2.6. 

However, in our opinion, the rigorous assignment of products to covalent nitronic esters rather than to their structural isomers, which are true nitro compounds or ionic salts, is a more important and complex problem This problem involves difficulties, because ambident anions of nitro compounds (which are evident precursors of nitronates) have comparable O- and C-nucleophilicities and, therefore, the resulting substrates can belong to any of the above mentioned series. Incorrect structure assignments of derivatives of polynitro compounds prepared from tetranitromethane were made in former studies. In addition, the structures of nitronates assigned to some products in early studies, should not have been accepted without the use of modem spectral methods. 

On treatment of certain other tertiary aromatic amines with nitrous acid, it has been found that either C-nitroso compounds, nuclear nitro compounds, or jV-nitrosoamines are formed with loss of an alkyl group. In the case of the nitrodimethylanilines, the latter two types of reaction may occur. The formation of nitro-jV-nitrosomethylanilines predominate at room temperature, whereas the formation of polynitro compounds predominates at more elevated temperatures. The formation of nitrosoamines from iVW-dimethylanilines appears to be particularly favored when both ortho positions are occupied by nitro groups, although /V-nitroso compounds were also obtainable from other nitrodimethylanilines. The product of the reaction, of course, is an /V-nitroso secondary amine. 

Aromatic nitro compounds are generally stable but are frequently reactive, especially if they contain groups other than nitro groups in the meta position with respect to one another. As a class they constitute the most important of the military high explosives. They are also used as components of smokeless powder, in compound detonators, and in primer compositions. Liquid nitro compounds, and the mixtures which are produced as by-products from the manufacture of pure nitro compounds for military purposes, are used in non-freezing dynamite and other commercial explosives. The polynitro compounds are solvents for nitrocellulose. 

Redox potential strongly affects the rate and products resulting from explosives transformation [193], This effect was found for RDX in the study of adsorption and transformation of RDX in low-carbon aquifer soils [194], In this context, it is interesting to note that nonaromatic polynitro compounds such as RDX do not show any tendency to adsorb specifically on clay mineral. 

Polynitro compounds can probably be formed only from paraffins of fairly high molecular weight. 

A systematic study of the ultra-violet absorption spectra of polynitro compounds were recently carried out by Conduit [7], By comparing the spectra of isomeric dinitrobenzenes, Conduit came to the conclusion that steric hindrance is respon-siblefor the considerable deviation of the spectrum of o- dinitrobenzene from those of the two other isomers (Table 20). 

A review of kinetic data from low-temperature thermolysis of polynitro compounds was recently given by Zeman [201 j. 

X, and the p-xylene complex at 100-120°C. Charge transfer is a factor in the host-guest complex of 4-methyl-3,5-dinitrobenzoic acid with 2,6-dimethylnaphthalene.74 Charge transfer with tetranitrofluorenone has also been used to remove 60% of the dialkyldibenzothiophenes from petroleum that contains 1920 ppm sulfur, although no inclusion compound is involved.75 As polynitro compounds are often explosive, a better charge acceptor is needed. 

The paper presents a brief survey of available results obtained from studies of the initiation micro-mechanisms of polynitro compounds from the point of view of organic chemistry. Attention is also paid to the basic mechanisms of low-temperature thermal deeomposition of these compounds. With consideration of these results, the relationships have been specified and analyzed between the characteristics of impact and electric spark sensitivities, detonation and thermal decomposition, on the one hand, and C and N NMR chemical shifts of polynitro compounds, on the other. In the ease of the impact sensitivity, the said relationships involve the NMR chemical shifts of the atoms carrying the most reactive nitro groups. In the case of the remaining stimuli studied, the N shifts of nitrogen atoms in the most reactive nitro groups themselves are involved. It has been stated that the chemical micro-mechanisms of primary fission processes of molecules of polynitro compounds in the initiation by mechanical stimuli (inclusive of the detonation course) and electric spark should be the same as in the case of their low-temperature thermal decomposition. 

The results of determination of impact sensitivity detected on the basis of sound (see the Bruceton method) were taken from literature [66-70] and are presented in Tables 1 and 2 as drop energies, Edr (expressed in J). The tables also contain a survey of the polynitro compounds studied, including their code designations. 

The addition occurs in the presence of polymerization inhibitors such as copper stearate, aromatic polynitro compounds, or sterically hindered phenols and then sometimes requires days or weeks. In spite of the often tedious procedure the method is of great interest since, from cheap materials, it often affords good yields of compounds containing the phospholene ring system which is otherwise difficultly accessible. Compounds of type (1) and (2) have also considerable interest as efficient catalysts for the carbodiimide synthesis (cf. page 504). 

The classical example of the spectrum of a nitro compound is that of nitro-methane. It consists of two broad bands a higli intensity band at X ax = 210 nm (log = 4.2) and a weak band at X ,ax = 270 nm (log e— 1.3) which probably arise from 7r2 —and rtg — rrj transitions respectively. Theoretically a third band n —from the transition ns —is also present at a very low wave-length in the vacuum ultraviolet and is of low intenaty. Ultraviolet-spectra of nitroalkanes including polynitro compounds were described in detail by Slovetskii [6] and reviewed by Novikov et al. in their monograph [7]. 

From the aromatic ether with the aromatic polynitro compound m chloroform... 

Hence, from the standpoint of sensitivity to stimuh (i.e. the micromechanism of initiation) attention is predominantly focused on organic polynitro compounds [1-4,6,37,39,60], and more recently of heavy metal... 

The polynitro compoimds in Fig. 15 fall into three classes. Each of them includes compounds with a characteristic range of values for thermolysis rate constants at their onset temperature of exothermic decomposition [166]. The given temperatures result from differential thermal analyses of the said compounds. This finding corresponds with the known relationships between impact sensitivities and thermal decomposition characteristics of polynitro compounds [16,89,148]. This means that some relationship exists between... 

Up-Pumping [1,74]. As already mentioned in Sect. 3.1, the author consulted a number of specialists in advance about his ideas. However, in this way he introduced into his model the ideas of primary fragmentation of EMs under extreme conditions. Nevertheless, he enriched the theory of initiation of explosive transformations of EMs by introducing significant ideas about transfer of initiation impulse to molecules in the crystal lattice of these materials. Experimental verification of this model is absent to date. In Dlott s opinion [1,74] the initiation by impact is a particular case of initiation by mechanical impulses (Low Velocity Initiation). Also [105] (Sect. 3.3.4) clearly documents the difference between the initiations by impact and by shock, though the authors do not call attention to this fact. Both the cited facts agree with study results of initiation reactivity of polynitro compounds by means of physical organic chemistry (Sects. 4.7 and 4.11), where the initiation by impact is treated separately from the set of initiations by shock, electric spark and heat. 

The results of the Excitonic model by Kuklja and Kunz [15,59,65-67] are in concordance with experimental findings obtained by low-temperature decomposition of polynitro compounds. The outputs from this model also correspond with results from the application of physical organic chemistry to the study of initiation reactivity of EMs (POC model). Both these models are also supported by the results obtained by Raikova and likholatov [118], who found that the Arrhenius parameters in both the detonation transform-... 

Polynitro compounds with aromatic hydrocarbons give solid derivatives, many of which are suitable for identification purposes. These addition compoimds are usually intensely colored and are formed by the mixing of both components in a suitable solvent (benzene, methanol, ethanol, chloroform) they can also crystallize from a melt of both components. The ability of nitro compounds to form the mentioned complexes increases with the number of nitro groups in the molecule. The presence of halogens, amino groups, and hydroxy groups can also increase this ability, while methyl groups have an opposite effect. 

Dibenzothiophene acts as a 7r-electron donor and readily forms complexes with known electron acceptors. In such cases the electronic spectrum of a solution of the two compounds shows a new absorption band, usually in the visible region. The order of donor strengths of several o,o -bridged biphenyls has been estimated from their respective charge-transfer spectra and found to be carbazole > fluorene > dibenzothiophene >dibenzofuran. Dibenzothiophene forms complexes with tetracy-anoethylene, various polynitro derivatives of fluorenone, > naphthalene-1,4,5,8-tetracarboxylic acid dianhydride, and tetra-methylmic acid. ... 

Nitration via diazotisation has been extensively used for the synthesis of isomeric dinitronaphthalenes. Ward and co-workers used nitration via diazotisation to prepare 3,3, 4,4 -tetranitrobiphenyl from 3,3 -dinitrobenzidine, and 3,4,5-trinitrotoluene from 3,5-dinitro-4-toluidine. Ward and Hardy " prepared 1,4,6-trinitronaphthalene from 4,7-dinitro-1-naphthylamine. Korner and Contardi used the nitrate salts of aryldiazonium compounds for the synthesis of polynitro derivatives of benzene " and toluene. " " Accordingly,... 

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