Trinitrotoluene, sensitiveness

The enthalpy ol formation of trinitrotoluene (TNT) is —67 kj-mol", and the density of TNT is 1.65 g-cm-3. In principle, it could be used as a rocker fuel, with the gases resulting from its decomposition streaming out of the rocket to give the required thrust. In practice, of course, it would be extremely dangerous as a fuel because it is sensitive to shock. Explore its potential as a rocket fuel by calculating its enthalpy density (enthalpy released per liter) for the reaction... 

Water in the solid state forms mixtures that are very sensitive to impact with liquid fluorine, which, if they detonate, have the same disruptive property as trinitrotoluene. If water is in the liquid state, the explosion is instantaneous and equally violent. 

Several nitro compounds are soluble in chlorine trifluoride, but the solutions are extremely shock-sensitive. These include trinitrotoluene, hexanitrobiphenyl, hexanitrodiphenyl-amine, -sulfide or -ether. Highly chlorinated compounds behave similarly. 

An important demonstrated application of this artificial nose system is the high-speed detection of low levels of explosives and explosive-like vapors. Several sensors, based on Nile Red attached to silica microspheres, show high sensitivity to nitroaromatic compounds (NAC) within a mixture12. Different fluorescence response profiles were observed for several NAC s, such as 1,3,5-trinitrotoluene (TNT) and 1,3-dinitrobenzene (DNB), despite their similar structures. These responses were monitored at low concentrations of the NAC vapors (ca. 5 ppb) and at short vapor exposure... 

Hilmi and Luong [25] employed a gold working electrode, formed by electroless deposition onto the chip capillary outlet, for highly sensitive amperometric detection of nitroaromatic explosives [with a detection limit of 24 ppb trinitrotoluene (TNT)]. Analysis of a mixture of four explosives (TNT, 2,4-DNT,... 

Fia 6 Effect of A on shock sensitivity of various explosives. NQ-f is low-bulk-density nitroguanidine with hollow-needle crystals of about 5 n diam X 60-65 it long. NQ-h is the high-bulk-density material made up of solid particles of about GO-65 n diam. DATB, TNT, and Tetryl are, respectively, dia-minotrinitrobenzene, trinitrotoluene and trinitro-phenylmethylnitramine. RDX is cyclotrimethyl-enetrinitramine which contains 2.5% lubricant. Measurements were carried out with a standardized test (Ref 16) in which a 3.65-cm-diam test explosive confined in 0.55-cm-thick steel is the acceptor and polymethyl methacrylate is the gap material MGl = NCro filt ro uasiM i ... 

The relative impact sensitivity (0R) of the sample with respect to the impact sensitivity of a reference explosive, usually trinitrotoluene (TNT), is calculated by Equation 3.6 ... 

In general this substance has the same chemical properties as its dimethyl homo-logue, described above. It is a weaker explosive than the dimethyl derivative and shows only slight sensitiveness to impact (less than trinitrotoluene). It gives a lead block expansion of 220 cm3. 

A very important property of tetryl is its sensitiveness to initiation by a primer— hence its rapid rise in importance as an explosive for use in detonating caps, gains (boosters) etc. Martin [54] gives the following figures comparing the sensitiveness to initiation of tetryl and trinitrotoluene, under the influence of various primary explosives (Table 11). 

Tetryl and butyltetryl are alike in their physical and chemical properties. The latter is notable for its low sensitiveness to impact, very similar to that of trinitrotoluene. Since it is slightly more powerful than trinitrotoluene and at the same time highly sensitive to detonation by mercury fulminate, it was suggested (Davis [72]) for use in detonators, gains (boosters) and other initiating or priming charges. 

The explosive properties of hexanitrodiphenyl-/ -hydroxynitraminoethyl nitrate are similar to those of pentryl. It is slightly more stable on heating its ignition temperature lies between 390 and 400°C. It is somewhat less sensitive to impact than pentryl and rather more powerful (by 3%) in the lead block test. It requires a stronger initiator than pentryl, tetryl or picric acid, but a weaker one than trinitrotoluene. 

The substance (I) is a moderately powerful explosive it gives an expansion of 250 cm3 in the lead block. It is less sensitive to impact than trinitrotoluene. Its ignition temperature (195-200°C) is about the same as that of tetryl. It forms inflammable salts. The lead, thallous and potassium salts bum violently with a sharp report. 

According to these authors sensitiveness to impact is of the same order as that of trinitrotoluene. 

The substance is exceptionally sensitive to the action of acids. When mixed with picric acid, for example, it undergoes violent decomposition after 2 hours heating at 60°C. At 100°C decomposition ensues in 10-15 minutes. A mixture with trinitrotoluene is decomposed at 85°C. 

Crude TNT contains isomers and nitrated phenolic compounds resulting from side reactions. The usual method of purification is to treat crude TNT with 4% sodium sulfite solution at pH 8-9, which converts the unsymmetrical trinitro compounds to sulfonic acid derivatives. These by-products are then removed by washing with an alkaline solution. Pure TNT is then washed with hot water, flaked and packed. It is important to remove the waste acid and unsymmetrical trinitrotoluenes together with any by-products of nitration as they will degrade the TNT, reduce its shelf life, increase its sensitivity and reduce its compatibility with metals and other materials. Trace amounts of unsymmetrical trinitrotoluenes and by-products will also lower the melting point of TNT. TNT can be further recrystallized from organic solvents or 62% nitric acid. 

Alpha-Compounds, such as a-Mononitronaphtha-lene, a-Trinitrotoluene, etc are listed under the corresponding parent compels, such as Naphthalene, Toluene etc Alpha Particles as Initiators of Detonation, According to some investigators a-particles emitted by radium or other sources can, by irradiation, initiate the detonation of very sensitive expls, such as nitrogen iodide, but not of expls such as acerylides or azides. Nitrogen iodide can also be irradiated by fission products (See also Initiation of Explosives by Irradiation)... 

Amatol, developed by the British during the first World War, is made by mixing granulated ammonium nitrate with melted trinitrotoluene, and pouring or extruding the mixture into the shells where it solidifies. The booster cavity is afterwards drilled out from the casting. The explosive can be cut with a hand saw. It is insensitive to friction and is less sensitive to initiation and more sensitive to impact than trinitrotoluene. It is hygroscopic, and in the presence of moisture attacks copper, brass, and bronze. 

Secondary explosives, or high explosives, are generally less sensitive to heat and shock than primary explosives and are therefore safer to manufacture, transport, and handle. Most secondary explosives will simply burn rather than explode when ignited in air, and most can be detonated only by the nearby explosion of a primary initiator. Among the most common secondary explosives are nitroglycerin, trinitrotoluene (TNT), pentaerythritol tetranitrate (PETN), and RDX. 

In another approach, a fluorescent conjugated polymer was used as the material for the preparation of a chemosensor to detect 2,4,6-trinitrotoluene (TNT) and its related nitroaromatic compounds. To this end, microparticles, made of three-dimensionally cross-linked poly(l,4-phenylene vinylene) (PPV) via emulsion polymerization, were synthesized [61]. This material was chosen due to its high fluorescence intensity and sensitivity to changes in its microenvironment. The chemosensor was exposed to vapour containing different amounts of TNT and quenching of the polymer luminescence at 560 nm was observed after excitation at 430 nm. The dependence of the fluorescence signal in response to the analyte was described by a modified Stem-Volmer equation that assumes the existence of two different cavity types. The authors proposed the modified Stem-Volmer equation as follows ... 

Ammonium nitrate is used in explosives, and many commercial and military explosives contain ammonium nitrate as the major explosive ingredient. Ammonium nitrate is difficult to detonate, but, when sensitized with oil or mixed with other explosive materials, it can be detonated with a large booster-primer. Amatol is a mixture of trinitrotoluene (TNT) and granular ammonium nitrate and is a major conventional military explosive. The explosive ANFO is a mixture of ammonium nitrate and fuel oil. 

Slurry explosives consist of oxidizers (NH4N03 and NaN03), fuels (coals, oils, aluminum, other carbonaceous materials), sensitizers (trinitrotoluene, nitrostarch, and smokeless powder), and water mixed with a gelling agent to form a thick, viscous explosive with excellent water-resistant properties. Slurry explosives may be manufactured as cartridged units, or mixed on site. 

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