Aromatic explosives

Because of their favorable elemental compositions, heteroaromatic nitro compounds represent explosives of high performance (oxygen balance, density, heat of formation and VOD) compared with analogous aromatic explosives [136-138]. With this objective, Licht and co-workers have synthesized some methylnitramine substituted pyridines and triazines, established their structures and characterized them for thermal and impact sensitivities [139]. The data on impact sensitivity, however, indicate that tetryl may not be replaced by these explosives. 

Haderlein, S B., Weissnahr, K.W., Schwarzenbach, R.P. (1996) Specific adsorption of nitro-aromatic explosives and pesticides to clay minerals. Environ. Sci. Technol. 30, 612-622. 

Notice that the three oxidizing substituents are nitro groups (—N02). Virtually all the aromatic explosives are oxidized principally by this substituent group, with the occasional addition of one or more of the others. 

In toluene, as well as with many other monosubstituted benzenes, the substitution group (methyl, in the case of toluene) acts as an electron donor. This counters the electron-withdrawing effect of the previously substituted nitro groups and allows higher local nitronium ion activity, thus allowing a much easier trinitration step. This is the key, then, to inexpensive synthesis of trinitro-aromatic explosives. Figure 3.5 is the TNT molecule, the first, and most important (as far as quantity of production goes) of the monosubstituted TNBs. 

Table 3.2 Physical Properties of Some Aromatic Explosives...

Going from one of the most sensitive of the aromatic explosives to one of the very least sensitive, we have TATB (Figure 3.18). This is a new, very insensitive, high explosive that is finding broad use in nuclear weapons development. The extreme degree of insensitiveness boosts the safety in handling and in accident situations, which is so crucial in that particular application. It is made by direct nitration of 1,3,5-trichlorobenzene to 1,3,5-trichloro-2,4,6-trinitrobenzene. This, in turn, is then converted to the 1,3,5-triamino- by amine substitution of the three chlorine atoms. 

These preceeding nine groups constitute the estimation of TMD for aliphatic explosives. The following four groups are for estimation of TMD of aromatic explosives. 

In the preliminary stage of explosion, the incomplete reactions are very common. The quenching or freezing impact of balance reaction deviates products from expected results, and produces a lot toxic gases, especially in composite explosives. In liquid explosives, addition of sensitizers with high reaction activities (such as nitroglycerine, hexagon, hydrazine nitrate, hydrazine perchlorate, aromatic explosives, etc.) helps to complete explosive reactions and reduce the production of toxic... 

An additional useful test is to distil the acid or its sodium salt with soda lime. Heat 0.5 g. of the acid or its sodium salt with 0 2 g. of soda lime in an ignition tube to make certain that there is no explosion. Then grind together 0-5 g. of the acid with 3 g. of soda hme, place the mixture in a Pyrex test-tube and cover it with an equal bulk of soda hme. Fit a wide dehvery tube dipping into an empty test-tube. Clamp the tube near the mouth. Heat the soda lime first and then the mixture gradually to a dull-red heat. Examine the product this may consist of aromatic hydrocarbons or derivatives, e.g., phenol from sahcyUc acid, anisole from anisic acid, toluene from toluic acid, etc. 

Aluminum bromide and chloride are equally active catalysts, whereas boron trifluoride is considerably less active probably because of its limited solubiUty in aromatic hydrocarbons. The perchloryl aromatics are interesting compounds but must be handled with care because of their explosive nature and sensitivity to mechanical shock and local overheating. 

Polymerization and GycliZation. Acetylene polymerizes at elevated temperatures and pressures which do not exceed the explosive decomposition point. Beyond this point, acetylene explosively decomposes to carbon and hydrogen. At 600—700°C and atmospheric pressure, benzene and other aromatics are formed from acetylene on heavy-metal catalysts. 

Organic Reactions. Nitric acid is used extensively ia iadustry to nitrate aHphatic and aromatic compounds (21). In many iastances nitration requires the use of sulfuric acid as a dehydrating agent or catalyst the extent of nitration achieved depends on the concentration of nitric and sulfuric acids used. This is of iadustrial importance ia the manufacture of nitrobenzene and dinitrotoluene, which are iatermediates ia the manufacture of polyurethanes. Trinitrotoluene (TNT) is an explosive. Various isomers of mononitrotoluene are used to make optical brighteners, herbicides (qv), and iasecticides. Such nitrations are generally attributed to the presence of the nitronium ion, NO2, the concentration of which iacreases with acid strength (see Nitration). 

To minimize the formation of fuhninating silver, these complexes should not be prepared from strongly basic suspensions of silver oxide. Highly explosive fuhninating silver, beheved to consist of either silver nitride or silver imide, may detonate spontaneously when silver oxide is heated with ammonia or when alkaline solutions of a silver—amine complex are stored. Addition of appropriate amounts of HCl to a solution of fuhninating silver renders it harmless. Stable silver complexes are also formed from many ahphatic and aromatic amines, eg, ethylamine, aniline, and pyridine. 

Dry methylene chloride does not react with the common metals under normal conditions however, a reaction with aluminum can be initiated, sometimes explosively, by the addition of small amounts of other halogenated solvents or an aromatic solvent (7). Iron catalyzes the reaction, and this can be significant in the handling and storage of methylene chloride and in the formulation of products, eg, in aluminum aerosol containers of pigmented paints, where the conditions necessary for the reaction are commonly found. A typical reaction in this process is shown in equation 2. 

Liquid/hquid reactions of industrial importance are fairly numerous. A hst of 26 classes of reactions with 61 references has been compiled by Doraiswamy and Sharma Heterogeneou.s Reactions, Wiley, 1984). They also indicate the kind of reactor normally used in each case. The reactions range from such prosaic examples as making soap with alkali, nitration of aromatics to make explosives, and alkylation of C4S with sulfuric acid to make improved gasoline, to some much less familiar operations. 

The cure reaction of structural acrylic adhesives can be started by any of a great number of redox reactions. One commonly used redox couple is the reaction of benzoyl peroxide (BPO) with tertiary aromatic amines. Pure BPO is hazardous when dry [39]. It is susceptible to explosion from shock, friction or heat, and has an autoignition temperature of 79°C. Water is a very effective stabilizer for BPO, and so the initiator is often available as a paste or a moist solid [40], The... 

POTASSIUM SALTS OF NITRO-AROMATIC DERIVATIVES, explosive 0158 ... 

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