Aromatic nitro compounds explosive properties

Numerous aromatic nitro compounds have explosive properties, and thus it is important to understand the role that enthalpy of formation has on the sensitivity and long-term stability of these compounds. We will examine three nitro-substituted aromatic families for which thermochemical data can be found in the literature2,84 derivatives of nitrobenzene, aniline and toluene. The choice of these three families allows us to compare the various electronic effects exerted by the parent functional group. The parent compounds differ electronically with respect to the aromatic ring in that ... 

Nitrations giving a complex mixture of products are not useful in organic chemistry or for the synthesis of explosives, and so, another route to the required product should be considered which is more selective. Although it is acceptable for commercial explosives to contain a mixture of aromatic nitro compounds, military explosives are almost always single compounds with well-defined physical properties. 

Cyclonite is a very important explosive. The outstanding properties of RDX as an explosive are high chemical stability, not much lower than aromatic nitro compounds and high explosive power which considerably surpasses that of aromatic nitro compounds such as TNT and picric acid. RDX has a detonation velocity of8600 ms"1 and a detonation pressure of 33.8 GPa at a density of 1.77 gem"3. RDX is used in mixtures with TNT (Hexotols, Cyclotols, Compn. B) wax (Composition A) aluminum (Hexals) aluminum and TNT (HBX, Hexotonal, Torpex) etc. 

With the development of the organic chemical industry, aromatic nitro compounds of the TNT type were introduced as ingredients of composite explosives. TNT is preferable to picric acid since it has no acidic properties and hence is much less reactive. Mixtures with TNT and similar nitro compounds showed an excellent chemical stability. 

The explosive properties of mixtures with ammonium nitrate depend on the quantitative relationship between the oxidizing agent and the explosive or combustible substance. According to Parisot and Laffitte s [9, 47] investigations the explosive properties of mixtures of aromatic nitro compounds with ammonium nitrate vary with the change in composition of the system in an almost rectilinear manner. The graph in Fig. 69 shows how the rate of detonation depends on the composition of mixtures of tetryl or picric acid with ammonium nitrate. T. Urbanski et al. [48] also obtained a rectilinear relationship for nitrostarch mixtures with ammonium or sodium nitrate (Fig. 71, p. 265). 

Of the hydrocarbons toluene is the only one which nitrates sufficiently easily and yields a product which has the proper physical and explosive properties. Trinitrotoluene is the most widely used of the pure aromatic nitro compounds. It melts at such temperature that it can be loaded by pouring. It is easily and surely detonated, and is insensitive to shock, though not insensitive enough to penetrate armor-plate without exploding until afterwards. It is powerful and brisant, but less so than trinitrobenzene which would offer certain advantages if it could be procured in sufficient quantity. 

The most studied kinds of explosives are nitroaromatic explosives and their metabolites. Therefore, the emphasis of this review is on properties of nitroaromatic explosives, rather than propellants, pyrotechnics, or munitions, and their interactions with soils. Nitroaromatic explosives are toxic, and their environmental transformation products, including arylamines, arylhydroxyl-amines, and condensed products such azoxy- and azo-compounds, are equally or more toxic than the parent nitroaromatic [3]. Aromatic amines and hydroxylamines are implicated as carcinogenic intermediates as a result of nitrenium ions formed by enzymatic oxidation [4], Aromatic nitro compounds... 

Aromatic nitro compounds which in ortho position have azido group can readily be transformed into benzofuroxanes (31, 33). An excellent review on furoxanes was written by Kaufman and Picard [206]. Recent works on the structure of benzotrifuroxane were also published on X-ray analysis [207, 208), vibrational and Raman spectra [209 210], nitrogen NMR [211], carbon 13 NMR [212]. Explosive properties were also discussed [213]. 

These oppositely contracted properties explain the various attempts which have been made to provide an explosive, which shall combine in Itself only the advantages of both classes of explosivej -that is to say a compound, which, in addition to the stability and non-sensitiveness of the aromatic nitro compounds exhibits the degree of energy of the ethereal salts of nitric acid. a result of these attempts hitherto obtained, certain tetranitrated benzene derivatives with the only recently prepared tetranitrani-line are the chief. These compounds are most certainly... 

Now according to the present Invention it has been found that hexamethylenetetramine, the well know n condensation product obtained from formaldehyde and ammonia, yields, when suitably treated with concentrated nitric acid, an extraordinarily powerful explosive compound, which combines in itself in an absolutely ideal manner the favourable properties of the ethereal salts of nitric acid and the aromatic nitro compounds. 

From these remarks U will therefore be clear, that in eye lotrim e thyle net rin Ur amine v/e have a perfectly new, hitherto unknown explosive, which combines in itself in an ideal way the advantages both of the etliereal salts of xiitric acid and also those of the aromatic nitro compounds, com bined with remarkable stability and non-sensitiveness while it surpasses all hitherto known and practically usa blc explosives in energy, shattering power and density and combines with these extraordinary properties in an explosive respect many advantages also as regards sanitary conditions. 

Refs 1) Beil, not found 2) C.A. Taylor E.P. Buxton, The Explosive Properties of the Silver Salts of Some of the Nitro-Aromatic Compounds and Silver Oxalate , ArmyOrdn 7, 68 (1926) CA 22, 3571 (1926) 3) W. 

Allhougli niiraie esters continue to be widely used and are important explosives their cliemical properties arc described to a much lesser extent than those of C nitro compounds. This is understandable when considering the wide use of C-nitro comjHiuiids. particularly aromatic ones, not only as explosives but in a great variety of uses as intermediates and finished products, l or this reason the excellent monograph of l atai. series edited by M. Feuer (1). does not cuniatn a chapter on 0 nitro compounds and the only review papers dedicated solely to O nitro compounds were by Boschan. Merrow, Van Dolah (2] and Connon 3l. 

Nitro Compounds as Explosives.—Nitro compounds prepared from aromatic hydrocarbons and certain of their derivatives were very important explosives used in the recent war. The compounds differ markedly in the properties which are characteristic of explosives namely, (1) sensitiveness to shock, (2) explosive force, and (3) the velocity of the explosion through the substance. If (1) is very high the explosive can not be transported very safely (2) determines the amount of the explosive to be used if (3) is very high the pressure is developed to its maximum so suddenly that rupture of the gun in which it is used may take place. Substances which are very sensitive to shock are used as detonators or boosters a small amount of the material is exploded by the trigger and the explosive wave set up causes the explosion of the less sensitive material. Mercury fulminate, lead azide, Pb(Ns)2, and several nitro derivatives of aniline (see below) are used for this purpose. 

Agrawal et al. reported the synthesis of BTDAONAB (Fig. 1.3c) which does not melt below 550 °C and is considered to be a better and thermally more stable explosive than TATB. According to the authors, this material has a very low impact (21J), no friction sensitivity (> 360 N) and is thermally stable up to 550 °C. These reported properties makes BTDAONAB superior to all of the nitro-aromatic compounds which have been discussed. BTDAONAB has a VoD of 8300 m/s while TATB is about 8000 m/s [Agrawal et al., Ind. J. Eng. Mater Sci., 2004,11,516-520 Agrawal et al., Central Europ.. Energ. Mat. 2012, 9(3), 273-290.]... 

Nitrobenzene is considered as a basic model system for studying molecular interactions and fundamental properties of nitro-aromatic compounds. They are essential compounds for manufacturing of explosives, pesticides and other chemicals. "... 

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