TNT

Source: Wikipedia, the free encyclopedia.
For other uses, see TNT (disambiguation).
2,4,6-Trinitrotoluene
solid trinitrotoluene
Names
Preferred IUPAC name
2-Methyl-1,3,5-trinitrobenzene[citation needed]
Other names
  • Trinitrotoluene
  • 2,4,6-Trinitromethylbenzene
  • 2,4,6-Trinitrotoluol
  • TNT, Tolite, Trilite, Trinitrotoluol, Trinol, Tritolo, Tritolol, Triton, Tritone, Trotol, Trotyl
Identifiers
3D model (
JSmol
)
Abbreviations TNT
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard
 100.003.900 Edit this at Wikidata
EC Number
  • 204-289-6
KEGG
RTECS number
  • XU0175000
UNII
UN number
0388, 0389
– Mixtures with trinitrobenzene, hexanitrostilbene
  • InChI=1S/C7H5N3O6/c1-4-6(9(13)14)2-5(8(11)12)3-7(4)10(15)16/h2-3H,1H3 ☒N
    Key: SPSSULHKWOKEEL-UHFFFAOYSA-N ☒N
  • InChI=1/C7H5N3O6/c1-4-6(9(13)14)2-5(8(11)12)3-7(4)10(15)16/h2-3H,1H3
  • InChI=1/C7H5N3O6/c1-4-2-3-5(8(11)12)7(10(15)16)6(4)9(13)14/h2-3H,1H3
    Key: FPKOPBFLPLFWAD-UHFFFAOYAR
  • Cc1c(cc(cc1[N+](=O)[O-])[N+](=O)[O-])[N+](=O)[O-]
Properties
C7H5N3O6
Molar mass 227.132 g·mol−1
Appearance Pale yellow solid. Loose "needles", flakes or prills before melt-casting. A solid block after being poured into a casing.
Density 1.654 g/cm3
Melting point 80.35 °C (176.63 °F; 353.50 K)
Boiling point 240.0 °C (464.0 °F; 513.1 K) (decomposes)[1]
0.13 g/L (20 °C)
Solubility in ether, acetone, benzene, pyridine soluble
Vapor pressure 0.0002 mmHg (20°C)[2]
Explosive data
Shock sensitivity Insensitive
Friction sensitivity Insensitive to 353 N
Detonation velocity 6900 m/s
RE factor
 1.00
Hazards
GHS labelling:
GHS01: Explosive GHS06: Toxic GHS08: Health hazard GHS09: Environmental hazard
Danger
H201, H301, H311, H331, H373, H411
P210, P273, P309+P311, P370+P380, P373, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 4: Readily capable of detonation or explosive decomposition at normal temperatures and pressures. E.g. nitroglycerinSpecial hazards (white): no code
2
1
4
Lethal dose or concentration (LD, LC):
795 mg/kg (rat, oral)
660 mg/kg (mouse, oral)[3]
500 mg/kg (rabbit, oral)
1850 mg/kg (cat, oral)[3]
NIOSH (US health exposure limits):
PEL (Permissible)
 TWA 1.5 mg/m3 [skin][2]
REL (Recommended)
 TWA 0.5 mg/m3 [skin][2]
IDLH
(Immediate danger)
 500 mg/m3[2]
Safety data sheet (SDS) ICSC 0967
Related compounds
Related compounds
 picric acid
hexanitrobenzene
2,4-Dinitrotoluene
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Trinitrotoluene (

charge transfer salts
.

History

TNT was first prepared in 1863 by German chemist Julius Wilbrand[6] and originally used as a yellow dye. Its potential as an explosive was not recognized for three decades, mainly because it was too difficult to detonate because it was less sensitive than alternatives. Its explosive properties were discovered in 1891 by another German chemist, Carl Häussermann.[7] TNT can be safely poured when liquid into shell cases, and is so insensitive that in 1910 it was exempted from the UK's Explosives Act 1875 and was not considered an explosive for the purposes of manufacture and storage.[8]

The German armed forces adopted it as a filling for artillery shells in 1902. TNT-filled armour-piercing shells would explode after they had penetrated the armour of British capital ships, whereas the British Lyddite-filled shells tended to explode upon striking armour, thus expending much of their energy outside the ship.[8] The British started replacing Lyddite with TNT in 1907.[9]

The

nitrotoluene isomer byproducts from the nitrating reactions.[10]

  • Chunks of explosives-grade TNT
    Chunks of explosives-grade TNT
  • Trinitrotoluene melting at 81 °C (178 °F)
    Trinitrotoluene melting at 81 °C (178 °F)
  • M795 artillery shells with fuzes fitted, labelled to indicate a filling of TNT
    M795 artillery shells with fuzes
    fitted, labelled to indicate a filling of TNT
  • M107 artillery shells. All are labelled to indicate a filling of "Comp B" (mixture of TNT and RDX) and have fuzes fitted
    M107 artillery shells. All are labelled to indicate a filling of "Comp B" (mixture of TNT and RDX) and have fuzes fitted
  • A group of M120 Rak mortar shells. The dark green shells on the left are stencilled to indicate a filling of TNT
    A group of M120 Rak mortar shells. The dark green shells on the left are stencilled to indicate a filling of TNT
  • Analysis of TNT production by branch of the German armed forces between 1941 and the first quarter of 1944, shown in thousands of tons per month
    Analysis of TNT production by branch of the German armed forces between 1941 and the first quarter of 1944, shown in thousands of tons per month
  • Detonation of the 500-ton TNT explosive charge as part of Operation Sailor Hat in 1965. The passing blast-wave left a white water surface behind and a white condensation cloud is visible overhead.
    Detonation of the 500-ton TNT explosive charge as part of Operation Sailor Hat in 1965. The passing blast-wave left a white water surface behind and a white condensation cloud is visible overhead.

Preparation

In industry, TNT is produced in a three-step process. First,

red water and is a significant pollutant and waste product of TNT manufacture.[11]

Control of

exothermic and carries with it the risk of a runaway reaction leading to an explosion.[citation needed
]

In the laboratory, 2,4,6-trinitrotoluene is produced by a two-step process. A nitrating mixture of concentrated nitric and sulfuric acids is used to nitrate toluene to a mixture of mono- and di-nitrotoluene isomers, with careful cooling to maintain temperature. The nitrated toluenes are then separated, washed with dilute

fuming nitric acid and sulfuric acid.[citation needed
]

Applications

TNT is one of the most commonly used explosives for military, industrial, and mining applications. TNT has been used in conjunction with

hydraulic fracturing (popularly known as fracking), a process used to recover oil and gas from shale formations. The technique involves displacing and detonating nitroglycerin in hydraulically induced fractures followed by wellbore shots using pelletized TNT.[12]

TNT is valued partly because of its insensitivity to shock and friction, with reduced risk of accidental detonation compared to more sensitive explosives such as nitroglycerin. TNT melts at 80 °C (176 °F), far below the temperature at which it will spontaneously detonate, allowing it to be poured or safely combined with other explosives. TNT neither absorbs nor dissolves in water, which allows it to be used effectively in wet environments. To detonate, TNT must be triggered by a pressure wave from a starter explosive, called an explosive booster.[13]

Although blocks of TNT are available in various sizes (e.g. 250 g, 500 g, 1,000 g), it is more commonly encountered in

synergistic
explosive blends comprising a variable percentage of TNT plus other ingredients. Examples of explosive blends containing TNT include:

Explosive character

Upon detonation, TNT undergoes a decomposition equivalent to the reaction

2 C7H5N3O6 → 3 N2 + 5 H2 + 12 CO + 2 C

plus some of the reactions

H
2 + CO → H
2O + C

and

2 CO → CO
2 + C.

The reaction is

exothermic but has a high activation energy in the gas phase (~62 kcal/mol). The condensed phases (solid or liquid) show markedly lower activation energies of roughly 35 kcal/mol due to unique bimolecular decomposition routes at elevated densities.[20] Because of the production of carbon, TNT explosions have a sooty appearance. Because TNT has an excess of carbon, explosive mixtures with oxygen-rich compounds can yield more energy per kilogram than TNT alone. During the 20th century amatol, a mixture of TNT with ammonium nitrate, was a widely used military explosive.[citation needed
]

TNT can be detonated with a high velocity initiator or by efficient concussion.[21] For many years, TNT used to be the reference point for the Figure of Insensitivity. TNT had a rating of exactly 100 on the "F of I" scale. The reference has since been changed to a more sensitive explosive called RDX, which has an F of I rating of 80.[22]

Energy content

See also: TNT equivalent
Cross-sectional view of Oerlikon 20 mm cannon shells (dating from c. 1945) showing color codes for TNT and pentolite fillings

The energy density of TNT is used as a reference point for many other explosives, including nuclear weapons, as their energy content is measured in equivalent tonnes (metric tons, t) of TNT. The energy used by

GJ/t.[23]

For safety assessments, it has been stated that the detonation of TNT, depending on circumstances, can release 2.673–6.702 GJ/t.[24]

The heat of combustion however is 14.5 GJ/t (14.5 MJ/kg or 4.027 kWh/kg), which requires that the carbon in TNT fully react with atmospheric oxygen, which does not occur in the initial event.[25]

For comparison, gunpowder contains 3 MJ/kg, dynamite contains 7.5 MJ/kg, and gasoline contains 47.2 MJ/kg (though gasoline requires an oxidant, so an optimized gasoline and O2 mixture contains 10.4 MJ/kg).[citation needed]

Detection

Various methods can be used to detect TNT, including optical and

zeptomolar (10−18 mol/m3) level.[26]

Safety and toxicity

TNT is poisonous, and skin contact can cause skin irritation, causing the skin to turn a bright yellow-orange color. During the

canary girls" or simply "canaries".[27]

People exposed to TNT over a prolonged period tend to experience anemia and abnormal liver functions. Blood and liver effects, spleen enlargement and other harmful effects on the immune system have also been found in animals that ingested or breathed trinitrotoluene. There is evidence that TNT adversely affects male fertility.[28] TNT is listed as a possible human carcinogen, with carcinogenic effects demonstrated in animal experiments with rats, although effects upon humans so far amount to none (according to IRIS of March 15, 2000).[29] Consumption of TNT produces red urine through the presence of breakdown products and not blood as sometimes believed.[30]

Some military testing grounds are contaminated with wastewater from munitions programs, including contamination of surface and subsurface waters which may be colored pink because of the presence of TNT. Such contamination, called "pink water", may be difficult and expensive to remedy.[citation needed]

TNT is prone to

fuze screw thread can form fire channels, increasing the risk of accidental detonation. Fuze malfunction can also result from the liquid migrating into the fuze mechanism.[31] Calcium silicate is mixed with TNT to mitigate the tendency towards exudation.[32]

Pink and red water

For the author, see Daniel Pinkwater.

Pink water and red water are two distinct types of

cyclotrimethylenetrinitramine (RDX) if the plant uses TNT/RDX mixtures, or HMX if TNT/HMX is used. Red water (also known as "Sellite water") is produced during the process used to purify the crude TNT. It has a complex composition containing more than a dozen aromatic compounds, but the principal components are inorganic salts (sodium sulfate, sodium sulfite, sodium nitrite and sodium nitrate) and sulfonated nitroaromatics.[citation needed
]

Pink and red water are colorless at the time of generation; the color is produced by

photolytic reactions under the influence of sunlight. Despite the names, red and pink water are not necessarily different shades; the color depends mainly on the duration of solar exposure. If exposed long enough, "pink" water may turn various shades of pink, red, rusty orange, or black.[35][36]

Because of the toxicity of TNT, the discharge of pink water to the environment has been prohibited in the US and many other countries for decades, but ground contamination may exist in very old plants. However, RDX and tetryl contamination is usually considered more problematic, as TNT has very low soil mobility. Red water is significantly more toxic and as such it has always been considered hazardous waste. It has traditionally been disposed of by evaporation to dryness (as the toxic components are not volatile), followed by incineration. Much research has been conducted to develop better disposal processes.[citation needed]

Ecological impact

Because of its suitability in construction and demolition, TNT has become the most widely used explosive and thus its toxicity is the most characterized and reported. Residual TNT from manufacture, storage, and use can pollute water, soil, the atmosphere, and the biosphere.[37]

The concentration of TNT in contaminated soil can reach 50 g/kg of soil, where the highest concentrations can be found on or near the surface. In September 2001, the United States Environmental Protection Agency (USEPA) declared TNT a pollutant whose removal is a priority.[38] The USEPA maintains that TNT levels in soil should not exceed 17.2 milligrams per kilogram of soil and 0.01 milligrams per litre of water.[39]

Aqueous solubility

Dissolution is a measure of the rate that solid TNT in contact with water is dissolved. The relatively low aqueous solubility of TNT causes solid particles to be continuously released to the environment over extended periods of time.[40] Studies have shown that TNT dissolves more slowly in saline water than in freshwater. However, when salinity is altered, TNT dissolves at the same speed.[41] Because TNT is moderately soluble in water, it can migrate through subsurface soil, and cause groundwater contamination.[42]

Soil adsorption

Adsorption is a measure of the distribution between soluble and sediment adsorbed contaminants following attainment of equilibrium. TNT and its transformation products are known to adsorb to surface soils and sediments, where they undergo reactive transformation or remained stored.[43] The movement or organic contaminants through soils is a function of their ability to associate with the mobile phase (water) and a stationary phase (soil). Materials that associate strongly with soils move slowly through soil. The association constant for TNT with soil is 2.7 to 11 L/kg of soil.

Hydrogen bonding and ion exchange
are two suggested mechanisms of adsorption between the nitro functional groups and soil colloids.

The number of functional groups on TNT influences the ability to adsorb into soil. Adsorption coefficient values have been shown to increase with an increase in the number of amino groups. Thus, adsorption of the TNT decomposition product 2,4-diamino-6-nitrotoluene (2,4-DANT) was greater than that for 4-amino-2,6-dinitrotoluene (4-ADNT), which was greater than that for TNT.[40] Lower adsorption coefficients for 2,6-DNT compared to 2,4-DNT can be attributed to the steric hindrance of the NO2 group in the ortho position.

Research has shown that in freshwater environments, with high abundances of Ca2+, the adsorption of TNT and its transformation products to soils and sediments may be lower than observed in a saline environment, dominated by K+ and Na+. Therefore, when considering the adsorption of TNT, the type of soil or sediment and the ionic composition and strength of the ground water are important factors.[45]

The association constants for TNT and its degradation products with clays have been determined. Clay minerals have a significant effect on the adsorption of energetic compounds. Soil properties, such as organic carbon content and cation exchange capacity have significant impacts on the adsorption coefficients.

Additional studies have shown that the mobility of TNT degradation products is likely to be lower "than TNT in subsurface environments where specific adsorption to clay minerals dominates the sorption process."

humic acids, in aquifer sediments, and soils".[45] From these models, it is predicted that TNT has a low retention and transports readily in the environment.[38]

Compared to other explosives, TNT has a higher association constant with soil, meaning it adheres more with soil than with water. Conversely, other explosives, such as RDX and HMX with low association constants (ranging from 0.06 to 7.3 L/kg and 0 to 1.6 L/kg respectively) can move more rapidly in water.[40]

Chemical breakdown

TNT is a reactive molecule and is particularly prone to react with reduced components of sediments or photodegradation in the presence of sunlight. TNT is thermodynamically and kinetically capable of reacting with a wide number of components of many environmental systems. This includes wholly abiotic reactants, like hydrogen sulfide, Fe2+, or microbial communities, both oxic and anoxic and photochemical degradation.[citation needed]

Soils with high clay contents or small particle sizes and high

dimers. Formation of the two monoamino transformation products, 2-ADNT and 4-ADNT, is energetically favored, and therefore is observed in contaminated soils and ground water. The diamino products are energetically less favorable, and even less likely are the triamino products.[citation needed
]

The transformation of TNT is significantly enhanced under anaerobic conditions as well as under highly reducing conditions. TNT transformations in soils can occur both biologically and abiotically.[45]

oxidation of methyl groups, reduction of nitro groups, and dimer formation."[40]

Evidence of the photolysis of TNT has been seen due to the color change to pink of TNT-containing wastewaters when exposed to sunlight. Photolysis is more rapid in river water than in distilled water. Ultimately, photolysis affects the fate of TNT primarily in the aquatic environment but could also affect the fate of TNT in soil when the soil surface is exposed to sunlight.[45]

Biodegradation

The ligninolytic physiological phase and manganese peroxidase system of fungi can cause a very limited amount of mineralization of TNT in a liquid culture, though not in soil. An organism capable of the remediation of large amounts of TNT in soil has yet to be discovered.[46] Both wild and transgenic plants can phytoremediate explosives from soil and water.[47]

See also

References

  1. ^ 2,4,6-Trinitrotoluene. inchem.org[dead link]
  2. ^ a b c d NIOSH Pocket Guide to Chemical Hazards. "#0641". National Institute for Occupational Safety and Health (NIOSH).
  3. ^ a b "2,4,6-Trinitrotoluene". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  4. ^ "Trinitrotoluene". Merriam-Webster.com Dictionary.
  5. ^ "Trinitrotoluene,". Dictionary.com Unabridged (Online). n.d.
  6. doi:10.1002/jlac.18631280206
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  12. Bibcode:1976sots.rept...98M. Archived from the original
    (PDF) on 2 October 2018. Retrieved 27 March 2015.
  13. ^ "TNT". www.ch.ic.ac.uk. Retrieved 2022-02-28.
  14. ISBN 978-0-85177-329-2
    .
  15. ^ U.S. Explosive Ordnance, Bureau of Ordnance. Washington, D.C.: U.S. Department of the Navy. 1947. p. 580.
  16. ^ Military Specification MIL-C-401
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  18. ^ [secondary source] webpages:submarine torpedo explosive Archived 2013-01-02 at archive.today Retrieved 2011-12-02
  19. ^ scribd.com website showing copy of a North American Intelligence document see:page 167 Archived 2013-05-10 at the Wayback Machine Retrieved 2011-12-02
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  21. ^ Merck Index, 13th Edition, 9801
  22. ^ "Figure of Insensitivity | 1 Publications | 12 Citations | Top Authors | Related Topics". SciSpace - Topic. Retrieved 2023-07-21.
  23. ^ "Guide for the Use of the International System of Units (SI)". 2008. Retrieved 2024-03-25.
  24. ^ "Blast effects of external explosions (Section 4.8 Limitations of the TNT equivalent method)". 2011. p. 16. Archived from the original on 2016-08-10.
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  27. ^ "The Canary Girls: The workers the war turned yellow". BBC News. 2017-05-20. Retrieved 2021-02-07.
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  29. ^ "2,4,6-Trinitrotoluene". www.nlm.nih.gov.
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  34. ^ National Defense Center for Environmental Excellence. Pink Water Treatment Options (PDF) (Report). U.S. Army Environmental Center. Retrieved 2024-04-25.
  35. ^ a b Van Deuren J, Lloyd T, Chhetry S, Liou R, Peck J (January 2002). Remediation Technologies Screening Matrix and Reference Guide (Report) (4 ed.). U.S. Army Environmental Center. Retrieved 2024-04-25.
  36. ^ Burlinson NE, Kaplan LA, Adams CE (1973-10-03). Photochemistry of TNT: Investigation of the "Pink Water" Problem (PDF) (Report). U.S. Army Environmental Center. Retrieved 2024-04-25.
  37. ^ Ascend Waste and Environment (7 June 2015). The health and environmental impacts of hazardous wastes: Impact Profiles (PDF). awe.gov.au (Report). Retrieved 22 April 2022.
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  47. PMID 22996005
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