2,4,6-Trinitrotoluene

Description

2,4,6-Trinitrotoluene (TNT) is a yellow, odourless, unstable solid. TNT does not occur naturally in the environment. TNT is an explosive used in military shells, bombs, and grenades; in industrial uses; and in underwater blasting. TNT is a high explosive that is unaffected by ordinary shocks and therefore must be set off by a detonator. TNT is often mixed with other explosives such as ammonium nitrate to form amatol. Because it is insensitive to shock and must be exploded with a detonator, it is the most favoured explosive used in munitions and construction. TNT reacts violently, is potentially explosively, reacts with heavy metals, and is a chemical with risk of explosion if heated or struck.

Chemical Properties

TNT exists in five isomers; 2,4,6-trinitrotoluene is the most commonly used. It is a colorless to pale yellow odorless solid (pellets, cast blocks, and cast slabs) or crushed flakes.

Physical properties

Colorless to light yellow, odorless monoclinic crystals. Soluble in alcohol and ether; insoluble in water.

History

TNT is the abbreviation of the aromatic nitrated aromatic compound 2,4,6-trinitrotoluene. It is a pale-yellow crystalline solid that was first synthesized in 1863 by the German chemist Joseph Wilbrand (1811 1894), but it was not immediately used as an explosive. TNT is made by nitrating toluene using nitric acid, sulfuric acid, and oleum (a mixture of sulfuric acid and SO3). Nitration of toluene occurs in stages, with the nitro units added sequentially in a stepwise process as the reaction proceeds. The last nitro unit is accomplished by using oleum (SO3 dissolved in sulfuric acid). After nitration, unused acids are recycled, and the product is washed with sodium sulfite and water to remove impurities.
TNT is one of the most common explosives. Unlike nitroglycerin, TNT will not explode when subjected to signifi cant shock and friction. It is classifi ed as a secondary explosive, which means it requires an initiating explosive to detonate. The Germans began production of TNT in the last decade of the 19th century, and it was used in the mining industry. Military engineers adapted mining explosives for use in warfare, and TNT started to be incorporated in munitions in 1902. The first widespread use of TNT occurred during World War I. Between World War I and II, TNT replaced picric acid as the explosive of choice in munitions. It was also mixed with other compounds to produce more powerful explosives with unique characteristics. Amatol is a mixture containing between 40% and 80% ammonium nitrate and TNT. Pentolite is a mixture of PETN (pentaerythritol tetranitrate) and TNT. Another common explosive mixture is RDX (cyclotrimethylenetrinitramine) and TNT. RDX is an abbreviation for Royal Demolition Explosive.

Uses

2,4,6-Trinitrotoluene (TNT) is used as a high explosive in mining and in military. It is produced by nitration of toluene with a mixture of nitric and sulfuric acids.

Uses

TNT has limited use as a chemical intermediate in pharmaceuticals and for photographicchemicals. It is used to produce other nitrated compounds. Removing the methylgroup from TNT produces 1,3,5-trinitobenzene, and removing methyl and a nitro groupproduces 1,3-dinitrobenzenze (1,3-DNB). Both trinitrobenzene and dinitrobenzene can beused as explosives. Trinitrobenzene is more powerful than TNT but less sensitive to impact.Dinitrobenzene has been used in the production of nitrocellulose, which is used for smokelessgunpowder and guncotton.

Uses

Explosive, intermediate in dyestuffs and photographic chemicals.

Definition

triton: A nucleus of a tritium atom,consisting of a proton and two neutronsbound together; the ion T⁺ formed by ionization of a tritium atom. See also hydron.

Definition

ChEBI: 2,4,6-trinitrotoluene is a trinitrotoluene having the nitro groups at positions 2, 4 and 6. It has a role as an explosive. It is functionally related to a 1,3,5-trinitrobenzene.

General Description

A slurry of a yellow water-insoluble crystalline solid. Can burn, although difficult to ignite. When water has been driven off or evaporated the residue is easily ignited, burns vigorously, and is highly explosive . Produces toxic oxides of nitrogen during combustion. May explode under exposure to intense heat. Primary hazard is blast of an explosion, not flying projectiles or fragments.

Reactivity Profile

TRINITROTOLUENE may begin a vigorous reaction that culminates in a detonation if mixed with reducing agents, including hydrides, sulfides and nitrides. May explode in the presence of a base such as sodium hydroxide or potassium hydroxide even in the presence of water or organic solvents.

Health Hazard

Some are toxic and may be fatal if inhaled, swallowed or absorbed through skin. Contact may cause burns to skin and eyes. Fire may produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may cause pollution.

Health Hazard

The toxic effect of TNT are dermatitis, cyanosis, gastritis, yellow atrophy of the liver, somnolence, tremor, convulsions, and aplastic anemia. Sneezing, sore throat, and muscular pain have also been noted in people exposed to this compound. It is an irritant to skin, respiratory tract, and urinary tract. Prolonged exposure may produce liver damage. The oral LD50 value in rats is in the range 800 mg/kg.
Levine and coworkers (1990) have conducted a 6-month oral toxicity test of TNT in beagle dogs. The major toxic effects observed were hemolytic anemia, methemoglobinemia, liver injury, splenomegaly, and death. A dose of 32 mg/kg/day was lethal to the dogs.
TNT tested nongenotoxic to the bone marrow of mice and the liver of rats (Ashby et al. 1985). It produced a negative response at dose levels up to 1000 mg/kg in the liver assay. High levels of hemoglobin and red-colored urine in the TNT-treated rats suggest a possible carcinogenic hazard to the hemopoietic and urinary tissues of animals at toxic levels on chronic exposure (Ashby et al. 1985). .

Fire Hazard

TNT is a high explosive. In comparison to many other high explosives, it is insensitive to heat, shock, or friction. Small amounts may burn quietly without detonation. However, when heated rapidly or subjected to strong shock, it detonates. Its detonation temperature is 470°C (878°F) and its velocity is between 5.1 and 6.9 km/s. In combination with other explosives, TNT is widely used as a military and industrial explosive. Amatol, cyclonite, and tetrytol are some of the examples of such explosive combinations. Amatol is a composition of 80% ammonium nitrate and 20% TNT by mass. TNT itself has a very high brisance.
Products from the detonation of 1.5-2.0 kg of TNT in air- and oxygen-deficient atmospheres consisted of low-molecularweight gases and high-molecular-weight polycyclic aromatic hydrocarbons (Johnson et al. 1988). Greiner and associates (1988) examined the soots produced from the detonation of cast composites of TNT mixed with nitroguanidine or RDX in 1 atmosphere of argon. The soot contained 25 wt% diamond 4-7 nm in diameter, the IR spectrum and particle size of which resembled those from meteorites. .

Safety Profile

Suspected carcinogen. Poison by subcutaneous route. Moderately toxic by ingestion. Human systemic effects by ingestion: hallucinations or distorted perceptions, cyanosis, and gastrointestinal changes. Experimental reproductive effects. Mutation data reported. A skin irritant. Has been implicated in aplastic anemia. Can cause headache, weakness, anemia, liver injury. May be absorbed through skin. Flammable or explosive when exposed to heat or flame. Moderate explosion hazard; will detonate under strong shock. It detonates at around 24O℃ but can be distilled safely under reduced pressure. It is a comparatively insensitive explosive. In small quantities it will burn quietly if not confined. However, sudden heating of any quantity will cause it to detonate; the accumulation of heat when large quantities are burning will cause detonation. In other respects it is one of the most stable of all high explosives, and there are but a few restrictions for its handling. It is for this reason, from the military standpoint, that TNT is quantitatively the most used. It requires a fall of 130 cm for a 2 kg weight to detonate it. It is one of the most powerful high explosives. It can be detonated by the usual detonators and blasting caps (at least a No. 6). For full efficiency, the use of a highvelocity initiator, such as tetryl, is required. TNT is one of those explosives containing an oxygen deficiency. In other words, the addition of products that are oxygen rich can enhance its explosive power. Also monoand dinitrotoluene may be added for reduction of the temperature of the explosion and to make the explosion flashless. Various materials are added to TNT to make what are known as permissible explosives. TNT may be regarded as the equivalent of 40% dynamite and can be used underwater. It is also used in the manufacture of a detonator fuse known as cordeau detonant. For the military, TNT finds use in all types of bursting charges, includmg armor-piercing types, although it is somewhat too sensitive to be ideal for this purpose and has since been replaced to a great extent by ammonium picrate. It is a relatively expensive explosive and does not compete seriously with dynamite for general commercial use. Highly dangerous; explodes with shock or heating to 297°C. Various materials can reduce the explosive temperature: red lead - (to 192℃), sodium carbonate (to 218℃), potassium hydroxide (to 192°C). Mixtures with sodium dichromate + sulfuric acid may ignite spontaneously. Reacts with nitric acid + metals (e.g., lead or iron) to form explosive products more sensitive to shock, friction, or contact with nitric or sulfuric acids. Reacts with potassium hydroxide dissolved in methanol to form explosive acinitro salts. Bases (e.g., sodium hydroxide, potassium iodide, tetramethyl ammonium octahydrotriborate) induce deflagration in molten TNT. Can react vigorously with reducing materials. When heated to decomposition it emits highly toxic fumes of NOx. See also NITRO COMPOUNDS of AROMATIC HYDROCARBONS and EXPLOSIVES, HIGH.

Potential Exposure

TNT is used as an explosive, that is, as a bursting charge in military explosive shells, bombs, grenades, and mines; and an intermediate in dyestuffs and photographic chemicals.

Carcinogenicity

In bacterial and mammalian in vitro cell systems TNT is a direct-acting mutagen. However, inclusion of exogenous metabolic activation appears to abolish the genotoxicity. In vivo assays of TNT have not shown it to be genotoxic, suggesting that TNT may be reduced to nonmutagenic metabolic products in the whole animal.

Source

Generated as a waste from munitions and defense industries, leaching from unexploded land mines.
Drinking water standard: No MCLGs or MCLs have been proposed, however, a DWEL of 20 μg/L was recommended (U.S. EPA, 2000).

Environmental Fate

Biological. 4-Amino-2,6-dinitrotoluene and 2-amino-4,6-dinitrotoluene, detected in contaminated groundwater beneath the Hawthorne Naval Ammunition Depot, NV, were reported to have formed from the microbial degradation of 2,4,6-trinitrotoluene (Pereira et al., 1979). 2,4,6- Trinitrotoluene (220 μM) degraded in aerobic sludge containing molasses (3.3 g/L). Though 2,4,6- trinitrotoluene disappeared completed in 15 h, only 0.1% was mineralized to carbon dioxide. Under aerobic conditions, intermediate compounds reported in the biotransformation of 2,4,6- trinitrotoluene to 2,4,6-triaminotoluene were 4-hydroxyamino-2,6-dinitrotoluene, 4-amino-2,6-dinitrotoluene, 2,4-diamino-6-nitrotoluene, 2-hydroxyamino-4,6-dinitrotoluene, 2-amino-4,6- dinitrotoluene, 2,6-diamino-4-nitrotoluene. Under abiotic conditions (pH 2 to 3), the following hydroxylated compounds formed: 2-hydroxy-4,6-diaminotoluene, 2,6-dihydroxy-4-aminotoluene, 4-hydroxy-2,6-diaminotoluene, 2,4-dihydroxy-6-aminotoluene, and 2,4,6-trihydroxytoluene. Under biotic conditions (pH 7.0), two azo derivatives were produced: 2,2′,4,4′-tetraamino-6,6′- azotoluene and 2,2′,6,6′-tetraamino-4,4′-azotoluene (Hawari et al., 1998).
Chemical. Although no products were identified, 2,4,6-trinitrotoluene (1.5 x 10^-5 M) was reduced by iron metal (33.3 g/L acid washed 18 to 20 mesh) in a carbonate buffer (1.5 x 10^-2 M) at pH 5.9 and 15 °C. Based on the pseudo-first-order disappearance rate of 0.0330/min, the half-life was 21.0 min (Agrawal and Tratnyek, 1996). 2,4,6-Trihydroxytoluene was detected after 2,4,6- trinitrotoluene in water was heated to 100 °C (Hawari et al., 1998).
Will detonate upon heating (NIOSH, 1997).
2,4,6-Trinitrotoluene will not hydrolyze in water because it does not contain a hydrolyzable funcational group.

storage

TNT is stored in a permanent magazine, separated from combustible and oxidizable materials, initiators, and heat sources. It is shipped in amounts not exceeding 60 lb (27 kg) in weight in metal containers enclosed in wooden or fiberboard boxes.

Shipping

UN1356 Trinitrotoluene, wetted with not <30% water, by mass, Hazard Class: 4.1; Labels: 4.1-Flammable solid. UN0209 Trinitrotoluene or TNT, dry or wetted with < 30% water, by mass, Hazard Class: 1D; Labels:1DExplosive (with a mass explosion hazard); D-Substances or articles which may mass detonate (with blast and/or fragment hazard) when exposed to fire.

Purification Methods

Crystallise TNT from *benzene and EtOH. Then fuse (CARE) and allow to crystallise under vacuum. Gey, Dalbey and Van Dolah [J Am Chem Soc 78 1803 1956] dissolved TNT in acetone and added cold water (1:2:15), the precipitate was filtered off, washed free from solvent and stirred with five parts of aqueous 8% Na2SO3 at 50-60o for 10minutes. This was filtered, washed with cold water until the effluent was colourless, and air dried. The product was dissolved in five parts of hot CCl4, washed with warm water until the washings were colourless and TNT was recoverd by cooling and filtering. It was recrystallised from 95% EtOH and carefully dried over H2SO4. The dry solid should not be heated without taking precautions for a possible EXPLOSION. Work with small quantities. [Beilstein 5 H 347, 5 I 172, 5 II 268, 5 III 767, 5 IV 873.]

Toxicity evaluation

TNT increases UDP glucuronyl transferase in the liver and kidneys. It increases renal epoxide hydrolase activity. Animal studies have suggested covalent binding between TNT and macromolecular proteins, including serum albumin, hemoglobin (Hb), hepatic and renal proteins, and possibly lens protein. The Hb adduct was dose dependent. Macromolecular binding is likely to be correlated with toxic effects; however, it is unclear if a cause and effect relationship can be established. Formation of organic nitro radicals was also hypothesized based on hemolysis in glucose 6 phosphate dehydrogenase (G6PD)-deficient TNT workers. G6PD is a limiting factor in the maintenance of cellular glutathione, which protects against oxidative damage. TNT was also found to be oxidized oxyhemoglobin, resulting in methemoglobin formation.

Incompatibilities

Sensitive to shock and heat. Incompatible with initiating explosives, combustible materials. Aromatic nitro compounds, such as trinitrobenzene, range from slight to strong oxidizing agents. Keep away from strong reducing agents, including hydrides, alkali metals; aluminium and other metal powder; phosphorus; sulfides and nitrides, alkaline material, strong bases; contact may initiate vigorous reactions that culminates in a detonation. The aromatic nitro compounds may explode in the presence of a base such as sodium hydroxide or potassium hydroxide even in the presence of water or organic solvents. The aromatic nitro compounds may explode in the presence of a base such as sodium hydroxide or potassium hydroxide even in the presence of water or organic solvents. Incompatible with strong oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions.

Waste Disposal

TNT is dissolved in acetone and incinerated. The incinerator should be equipped with an afterburner and a caustic soda solution scrubber.