1.3.5- trinitrobenzene decomposition

TATB or 1,3,5-triamino-2,4,6-trinitrobenzene (C6H6N6Oe) is a yellow-brown crystalline solid that has excellent thermal stability and is known as a heat-resistant explosive. TATB has a decomposition point of 325°C. Its molecular arrangement provides lubricating and elastic properties. 

That the formation of molecular complexes (especially EDA complexes) can catalyse the decomposition of the cr-adduct has been discussed in Section n.E. Another possibility is that the substrate and catalyst (nucleophile or added base) form a complex which is then attacked by a new molecule of the nucleophile in this context catalysis need no longer be associated with proton removal. Thus, Ryzhakov and collaborators183 have recently shown that the N-oxides of 4-chloropyridine and 4-chloroquinoline act as jt-donors toward tetracyanoethylene and that the reactions of these substrates with pyridine and quinoline are strongly catalysed by the jr-acceptor. Similarly, the formation of a Meisenheimer complex between 1,3,5-trinitrobenzene and l,8-diazabicyclo[5,4,0]undec-7-ene in toluene has been assumed to take place via an association complex to explain the observed second-order in tertiary amine184. 

Polynitro derivatives of monocychc aromatic systems (trinitrobenzene, trinitrotoluene, tetranitro-iV-methylaniline, trinitrophenol, etc.) have long been used as explosives [1]. It has been found that a series of polynitroderivatives of biphenyl, diphenylmethane and 1,2-diphenylethylene (stilbene) are explosives liable to detonate on grinding or impact [2]. The same may be true of other polynitro derivatives of polycyclic systems not normally used as explosives (e.g. polynitro-fluorenones, -carbazoles, etc. Penta- and hexa-nitrobenzophenones are also high-energy explosives [3]. The thermal stability of 33 polynitroaromatics was studied by DTA [4]. Two empirical equations relating the heat of decomposition to the heat of detonation have been developed and used to calculate the heats of detonation for 47 polynitroaryl compoimds [5]. 

Kinetics of thermal decomposition of explosives 3-amino-5-nitro-l,2,4-triazole (ANTA) and its derivatives [38], l,3-bis(l,2,4-triazol-3-amino)-2,4,6-trinitrobenzene [39] and transition metal salts of NTO [40]. 

Adduct formation is followed by subsequent changes with both reactants, but the related spectral changes suggest that diverse decompositions of the adducts occur depending on the nucleophilic reagent. Although there is some analogy with the behavior of the trinitrobenzene adducts, these processes still await elucidation. 

It has been established experimentally (T. Urbanski, Kwiatkowski, Miladowski [22]) that the addition to pentaerythritol tetranitrate of such nitro compounds as nitrobenzene, nitrotoluene, dinitrobenzene, dinitrotoluene, trinitrobenzene, and trinitrotoluene, decreases its stability as determined by heating to 120-135°C. The degree of decomposition of PETN, heated alone or in mixtures, can be estimated in terms of the pH-values determining the acidity of the decomposition products (Table 32, Fig. 72). 

Jensen et al.16 also studied the decomposition of 5-ethoxythiatriazole in dibutyl phthalate solution in the presence of trichloroacetic acid, tripentylamine, 4-benzylpyridine, anhydrous aluminum chloride, or trinitrobenzene, but practically no effect on the reaction rate was observed. However, later experiments have shown that the decomposition can indeed by enhanced catalytically by Lewis acids under conditions where the catalyst is not sequestered by complex formation with the solvent.19 Thus the addition of aluminum chloride to 5-phenylthiatriazole in benzene causes a brisk evolution of nitrogen at room temperature, and if instead boron tribromide is added, a rather violent reaction sets in. However, when esters or ethers are used as... 

T.B. Brill, K.J. James, Kinetics and Mechanisms of Thermal Decomposition of Nitroaromatic Explosives, J. Phys. Chem., 93 (1993) 2667-2692. ibid Thermal Decomposition of Energetic Materials. 61 Perfidy in the Amino-2,4,6-Trinitrobenzene Series of Explosives, J. Phys. Chem. 97(34) (1993) 8752-8758. ibid. Thermal Decomposition of Energetic Materials. 62 Reconciliation of the Kinetics and Mechanisms of TNT on the Time Scale from Microseconds to Hours, J. Phys. Chem., 97(34) (1993) 8759-8763. 

It is characteristic that the new entrant methyl group assumes the ortho position to the nitro group and thus a substitution occurs which is similar to nucleophilic attack. Recently it has been found by Jackson and Waters [72] that higher nitrated benzene derivatives such as m- dinitrobenzene, or 1,3,5-trinitrobenzene, become homolytic hydrogen acceptors at temperatures of 80-100°C especially in the presence of the 2-cyano-2-propyl radical, which is formed by thermal decomposition of a,a -azo-bis-isobutyronitrile... 

In consequence of such drastic conditions of nitration several side reactions of oxidation and break-down processes take place, giving rise to the products mentioned above (trinitrobenzoic acid, trinitrobenzene, tetranitromethane). A decomposition reaction (p, 76) also gives off a large volume of carbon monoxide, which may form an explosive mixture with air. Several explosions of such mixtures have been described. 

Prepare a mixture by adding 2.7 grams of 5-cyano-1,3-diamino-2,4,6-trinitrobenzene (prepared in step 2), and 60 milliliters of 98% sulfuric acid into 30 milliliters of water. Then heat the mixture to 100 Celsius for 90 minutes. After 90 minutes, remove the heat source and allow the mixture to cool to room temperature. Afterwards, pour the mixture into 500 milliliters of ice water. Then filter-off the precipitated product, wash with 200 milliliters of water 2 times, and then vacuum dry or air-dry. The yield will be 2.6 grams of crude 5-carboxy-l,3-diamino-2,4,6-trinitrobenzene. Then reciystallize this cmde product from 300 milliliters of acetonitrile. After reciystallization, wash the product with 200 milliliters of cold water, and then vacuum dry or air-dry the product. The dry product will be in the form of yellow needles with a melting point of 240 Celsius (with decomposition). 

Other decarboxylations are noteworthy. Thermal decomposition of 2,4,6-trinitrobenzoic acid furnishes 1,3,5-trinitrobenzene in 46% yield. In an adaptation of a procedure for the decarboxylation of halogenated furoic acids with boiling quinoline and powdered copper, 2- and 3-nitro-benzofuran are prepared from nitro acids and 5-nitrothionaphthene is formed from the corresponding 2-carboxylic acid. ... 

Cosgrave and Owen [115] and Debenham and Owen [170] studied the decomposition of cyclonite at 195 C and 173-184 C respectively. Tlvey came to the conclusion that the initial decomposition takes place in the vapour phase and is followed by a more rapid decomposition in the liquid phase (e.g, a solution of cyclonite in 1,3,5-trinitrobenzene [170]). 

Properties Orthorhombic crystals. Mp 228.7C. Sublimes with decomposition, forming carbon dioxide and trinitrobenzene slightly soluble in water and benzene soluble in alcohol, ether, and acetone. Derivation Oxidation of 2,4,6-trinitrotoluene with chromic acid. 

Table 7.2 shows how frequently various nitroaromaticss and nitramines occur at explosives-contaminated sites with which die U.S. Army Cold Regions Research and Engineering Laboratory (CRREL) and the Missouri River Division (MRD) have been involved. TNT is the most common contaminant, occurring in approximately 80% of the soil samples found to be contaminated with explosives. Trinitrobenzene (TNB), which is a photochemical decomposition product of TNT, was found in between 40 and 50% of these soils. Dinitrobenzene (DNB), 2,4-dinitrotoluene (2,4-DNT), and 2,6-DNT, which are impurities in production-grade TNT, were found in less than 40% of the soils. Figure 7.2 shows the chemical structures of common explosive contaminants. 

The decomposition of some addition compounds of aromatic hydrocarbons (formed with picric acid, styphnic acid or trinitrobenzene) on an adsorbent column has been made use of for the preparation of pure hydrocarbons for spectral analysis. For example, chamazulene trinitrobenzene addition compound decomposes on alumina column. The pure hydrocarbon released is eluted with petroleum ether, leaving behind trinitrobenzene (which has high affinity for alumina) in the upper part of the column. This again can be eluted with more polar solvents. 

METHYL-l,3,5-TRINITROBENZENE (118-96-7) High explosive protect from shock, friction, concussion, and heat. Rapid heating will cause detonation. Slow decomposition occurs above 356°F/180°C. Explodes when heated above 450°F/232 C. Exposure to light may increase impact sensitivity. Strong oxidizers may cause fire. Contact with ammttnia... 

Finally, reactivity degree four (4) chemicals, the most dangerous group, are materials which are easily capable of detonation at normal temperatures, or may undergo explosive decomposition or reaction under normal conditions. Dibenzoyl peroxide, picric acid, tertiary butyl hydroperoxide, ethyl nitrite, and trinitrobenzene are representative of degree four (4) chemicals. 

Slow and careful heating of a small amount of material does not cause detonation. Trinitrobenzene is a flammable solid. It reacts vigorously with reducing snbstances. It emits highly toxic oxides of nitrogen on decomposition. 

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