TNT: Difference between revisions

{{Short description|Impact-resistant high explosive}}

{{cs1 config|name-list-style=vanc}}

{{Other uses}}

| Name = 2,4,6-Trinitrotoluene

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 458775807

| ImageFile2 = TNT Crystals2.jpg

| ImageSize2 =

| ImageAlt2 = solid trinitrotoluene

| PIN = 2-Methyl-1,3,5-trinitrobenzene<ref name="IUPAC">https://pubchem.ncbi.nlm.nih.gov/compound/87172748</ref>

| OtherNames = {{ubl|Trinitrotoluene|2,4,6-Trinitromethylbenzene|2,4,6-Trinitrotoluol|TNT, Tolite, Trilite, Trinitrotoluol, Trinol, Tritolo, Tritolol, Triton, Tritone, Trotol, Trotyl}}

|Section1={{Chembox Identifiers

| ChemSpiderID_Ref = {{chemspidercite|changed|chemspider}}

| ChemSpiderID = 8073

| ChEMBL_Ref = {{ebicite|changed|EBI}}

| ChEMBL = 1236345

| CASNo = 118-96-7

| UNNumber = [[List of UN Numbers 0201 to 0300|0209]] – ''Dry or wetted with < 30% water''<br />[[List of UN Numbers 0301 to 0400|0388, 0389]] – ''Mixtures with trinitrobenzene, hexanitrostilbene''

| PubChem = 8376

| DrugBank_Ref = {{drugbankcite|correct|drugbank}}

| StdInChI_Ref = {{stdinchicite|changed|chemspider}}

| StdInChI = 1S/C7H5N3O6/c1-4-6(9(13)14)2-5(8(11)12)3-7(4)10(15)16/h2-3H,1H3

| StdInChIKey_Ref = {{stdinchicite|changed|chemspider}}

| StdInChIKey = SPSSULHKWOKEEL-UHFFFAOYSA-N

| SMILES = Cc1c(cc(cc1[N+](=O)[O-])[N+](=O)[O-])[N+](=O)[O-]

| InChI = 1/C7H5N3O6/c1-4-6(9(13)14)2-5(8(11)12)3-7(4)10(15)16/h2-3H,1H3

| RTECS = XU0175000

| ChEBI_Ref = {{ebicite|correct|EBI}}

| KEGG_Ref = {{keggcite|changed|kegg}}

| KEGG = C16391

}}

|Section2={{Chembox Properties

| C=7 | H=5 | N=3 | O=6

| Appearance = Pale yellow solid. Loose "needles", flakes or [[prill]]s before melt-[[casting]]. A solid block after being poured into a casing.

| MeltingPtC = 80.35

| MeltingPt_notes =

| BoilingPtC = 240.0

| BoilingPt_notes = (decomposes)<ref>[http://www.inchem.org/documents/icsc/icsc/eics0967.htm 2,4,6-Trinitrotoluene]. inchem.org{{dead link|date=April 2021}}</ref>

| Solvent = [[diethyl ether|ether]], [[acetone]], [[benzene]], [[pyridine]]

| pKb =

| VaporPressure = 0.0002 mmHg (20°C)<ref name=PGCH/>

}}

|Section4={{Chembox Explosive

| DetonationV = 6900 m/s

|Section7={{Chembox Hazards

| ExternalSDS = [http://www.inchem.org/documents/icsc/icsc/eics0967.htm ICSC 0967]

| NFPA-F = 1

| NFPA-S =

| GHSPictograms = {{GHS exploding bomb}} {{GHS skull and crossbones}} {{GHS health hazard}} {{GHS environment}}

| GHSSignalWord = '''DANGER'''

| HPhrases = {{H-phrases|201|301|311|331|373|411}}

| PPhrases = {{P-phrases|210|273|309+311|370+380|373|501}}

| FlashPtC =

| AutoignitionPtC =

| PEL = TWA 1.5 mg/m³ [skin]<ref name=PGCH/>

| IDLH = 500 mg/m³<ref name=PGCH>{{PGCH|0641}}</ref>

| REL = TWA 0.5 mg/m³ [skin]<ref name=PGCH/>

| LD50 = 795 mg/kg (rat, oral)<br />660 mg/kg (mouse, oral)<ref name=IDLH>{{IDLH|118967|2,4,6-Trinitrotoluene}}</ref>

| LDLo = 500 mg/kg (rabbit, oral)<br />1850 mg/kg (cat, oral)<ref name=IDLH/>

|Section8={{Chembox Related

| OtherCompounds = [[picric acid]]<br />[[hexanitrobenzene]]<br />[[2,4-Dinitrotoluene]]}}

|Section6={{Chembox Pharmacology

| ATCCode_prefix =

| ATCCode_suffix =

| ATC_Supplemental =

}}

}}

'''Trinitrotoluene''' ({{IPAc-en|ˌ|t|r|aɪ|ˌ|n|aɪ|t|r|oʊ|ˈ|t|ɒ|lj|u|iː|n}}),{{refn|{{MerriamWebsterDictionary|Trinitrotoluene}}}}{{refn|{{Dictionary.com|Trinitrotoluene,}}}} more commonly known as '''TNT''' (and more specifically '''2,4,6-trinitrotoluene'''), and by its preferred [[IUPAC]] name '''2-methyl-1,3,5-trinitrobenzene'''<ref name="IUPAC"/>, is a [[chemical compound]] with the formula C₆H₂(NO₂)₃CH₃. TNT is occasionally used as a [[reagent]] in [[chemical synthesis]], but it is best known as an [[explosive material]] with convenient handling properties. The explosive yield of TNT is considered to be the [[TNT equivalent|standard comparative convention]] of [[bomb]]s and asteroid impacts. In [[chemistry]], TNT is used to generate [[Charge transfer complex|charge transfer salts]].

== History ==

TNT was first prepared in 1861 by German [[chemist]] [[Joseph Wilbrand]]<ref>{{cite journal|year=1861|title=Notiz über Trinitrotoluol|url=https://books.google.com/books?id=qmgTAAAAQAAJ&pg=PA178|journal=[[Annalen der Chemie und Pharmacie]]|volume=128|issue=2|pages=178–179|doi=10.1002/jlac.18631280206|author=Wilbrand, J.}}</ref> 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.<ref>{{cite book|author=Peter O. K. Krehl|title=History of Shock Waves, Explosions and Impact: A Chronological and Biographical Reference|url=https://books.google.com/books?id=PmuqCHDC3pwC&pg=PA404|year=2008|publisher=Springer Science & Business Media|isbn=978-3-540-30421-0|page=404}}</ref> TNT can be safely poured when liquid into shell cases, and is so insensitive that in 1910 it was exempted from the UK's [[History of fire safety legislation in the United Kingdom#Explosives_Act_1875|Explosives Act 1875]] and was not considered an explosive for the purposes of manufacture and storage.<ref name="brown">{{Cite book|title=The Big Bang: a History of Explosives|publisher=Sutton Publishing|year=1998|isbn=978-0-7509-1878-7|pages=[https://archive.org/details/bigbanghistoryof00brow/page/151 151–153]|author=Brown GI|url-access=registration|url=https://archive.org/details/bigbanghistoryof00brow/page/151}}</ref>

The German armed forces adopted it as a filling for [[artillery]] [[shell (projectile)|shells]] in 1902. TNT-filled [[Armour-piercing ammunition|armour-piercing]] shells would explode after they had penetrated the armour of British [[capital ship]]s, whereas the British [[Picric acid|Lyddite]]-filled shells tended to explode upon striking armour, thus expending much of their energy outside the ship.<ref name="brown"/> The British started replacing Lyddite with TNT in 1907.<ref>{{cite book |title=Arrows to Atom Bombs: A History of the Ordnance Board |author1=Norman Skentelbery |edition=2nd |publisher=Ordnance Board |year=1975 |page=99 |url=https://books.google.com/books?id=ySQGAAAAMAAJ}}</ref>

The [[United States Navy]] continued filling [[armour-piercing]] shells with [[Dunnite|explosive D]] after some other nations had switched to TNT, but began filling [[naval mine]]s, [[bomb]]s, [[depth charge]]s, and [[torpedo]] warheads with burster charges of crude grade B TNT with the color of brown sugar and requiring an [[explosive booster]] charge of granular crystallized grade A TNT for detonation. High-explosive shells were filled with grade A TNT, which became preferred for other uses as industrial chemical capacity became available for removing [[xylene]] and similar [[hydrocarbon]]s from the toluene feedstock and other [[nitrotoluene]] [[isomer]] byproducts from the nitrating reactions.<ref>{{Cite book|title=Naval Ordnance|publisher=Lord Baltimore Press|year=1921|pages=49–52|author=Fairfield AP}}</ref>

<gallery widths="200px" heights="200px">

File:Trinitrotoluen.JPG|Chunks of explosives-grade TNT

File:Tání TNT při 81 °C.JPG|Trinitrotoluene melting at {{convert|81|C|F}}

File:11th_Marine_Regiment_Desert_Fire_Exercise_130423-M-VH365-119.jpg|[[M795]] artillery shells with [[fuze]]s fitted, labelled to indicate a filling of TNT

Image:USMC-100414-M-5241M-001.jpg|[[M107 projectile|M107]] artillery shells. All are labelled to indicate a filling of "[[Composition B|Comp B]]" (mixture of TNT and [[RDX]]) and have [[fuze]]s fitted

File:X4_RAK_ammo.jpg|A group of [[M120 Rak]] mortar shells. The dark green shells on the left are stencilled to indicate a filling of TNT

File:TNT Allocations Germany.gif|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

File:TNT detonation on Kaho'olawe Island during Operation Sailor Hat, shot Bravo, 1965.jpg|[[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.

</gallery>

== Preparation ==

In industry, TNT is produced in a three-step process. First, [[toluene]] is [[nitration|nitrated]] with a mixture of [[sulfuric acid|sulfuric]] and [[nitric acid]] to produce [[mononitrotoluene]] (MNT). The MNT is separated and then renitrated to [[dinitrotoluene]] (DNT). In the final step, the DNT is nitrated to trinitrotoluene (TNT) using an [[anhydrous]] mixture of nitric acid and [[oleum]]. Nitric acid is consumed by the manufacturing process, but the diluted sulfuric acid can be reconcentrated and reused.

After nitration, TNT can either be purified by crystallization from an organic solvent or stabilized by a process called sulfitation, where the crude TNT is treated with aqueous [[sodium sulfite]] solution to remove less stable isomers of TNT and other undesired reaction products. The rinse water from sulfitation is known as [[#Pink and red water|red water]] and is a significant pollutant and waste product of TNT manufacture.<ref>{{cite book|title=Chemistry and Technology of Explosives|publisher=Pergamon Press|year=1964|isbn=978-0-08-010238-2|volume=1|pages=389–91|author=Urbanski T}}

Control of [[nitrogen oxide]]s in feed nitric acid is very important because free [[nitrogen dioxide]] can result in oxidation of the methyl group of toluene. This reaction is highly [[exothermic]] and carries with it the risk of a runaway reaction leading to an explosion.{{Cn|date=January 2021}}

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 [[sodium bicarbonate]] to remove oxides of nitrogen, and then carefully nitrated with a mixture of [[fuming nitric acid]] and sulfuric acid.{{Cn|date=January 2021}}

== 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.<ref name="recovery">{{cite journal|last1=Miller|first1=J. S.|last2=Johansen|first2=R. T.|date=1976|title=Fracturing Oil Shale with Explosives for In Situ Recovery.|journal=Shale Oil, Tar Sand and Related Fuel Sources|pages=151|url=https://web.anl.gov/PCS/acsfuel/preprint%20archive/Files/19_2_LOS%20ANGELES_04-74__0060.pdf|access-date=27 March 2015|bibcode=1976sots.rept...98M|archive-date=2 October 2018|archive-url=https://web.archive.org/web/20181002204137/https://web.anl.gov/PCS/acsfuel/preprint%20archive/Files/19_2_LOS%20ANGELES_04-74__0060.pdf|url-status=dead}}</ref>

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&nbsp;°C (176&nbsp;°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]].<ref>{{Cite web |title=TNT |url=https://www.ch.ic.ac.uk/vchemlib/mim/bristol/tnt/tnt_text.htm |access-date=2022-02-28 |website=www.ch.ic.ac.uk}}</ref>

Although blocks of TNT are available in various sizes (e.g. 250&nbsp;g, 500&nbsp;g, 1,000&nbsp;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:

* [[Amatex]] ([[ammonium nitrate]] and [[RDX]])<ref>{{cite book | isbn = 978-0-85177-329-2 | page = 100 | author = Campbell J | year = 1985 | publisher = Conway Maritime Press | location = London | title = Naval weapons of World War Two}}</ref>

* [[Amatol]] (ammonium nitrate<ref>{{cite book | location = Washington, D.C. | title = U.S. Explosive Ordnance, Bureau of Ordnance | year = 1947 | publisher = U.S. Department of the Navy | url = http://www.maritime.org/doc/ordnance/index.htm | pages = 580 }}</ref>)

* [[Baratol (explosive)|Baratol]] ([[barium nitrate]] and wax{{cn|date=April 2023}})

* [[Composition B]] (RDX and paraffin wax<ref>Military Specification MIL-C-401</ref>)

* [[Cyclotol]] (RDX)<ref>{{cite book |author = Cooper PW | year = 1996 | title = Explosives Engineering | publisher = Wiley-VCH | isbn = 978-0-471-18636-6}}</ref>

* [[Hexanite]]{{cn|date=April 2023}} ([[hexanitrodiphenylamine]]<ref>[http://www.dutchsubmarines.com/specials/special_torpedoes_mines.htm &#91;secondary source&#93; webpages:submarine torpedo explosive] {{Webarchive|url=https://archive.today/20130102095230/http://www.dutchsubmarines.com/specials/special_torpedoes_mines.htm |date=2013-01-02 }} Retrieved 2011-12-02</ref><ref>[https://www.scribd.com/doc/39682972/Encyclopedia-of-Explosives-A-Compilation-of-Principal-Explosives-Their-Characteristics-Processes-of-Manufacture-And-Uses-USA-1960 ''scribd.com'' website showing copy of a North American Intelligence document see:page 167] {{Webarchive|url=https://web.archive.org/web/20130510223600/http://www.scribd.com/doc/39682972/Encyclopedia-of-Explosives-A-Compilation-of-Principal-Explosives-Their-Characteristics-Processes-of-Manufacture-And-Uses-USA-1960 |date=2013-05-10 }} Retrieved 2011-12-02</ref>)

== 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

: {{chem|H|2}} + CO → {{chem|H|2|O}} + C

and

: 2 CO → {{chem|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.<ref name="Furman Kosloff Dubnikova Zybin pp. 4192–4200">{{cite journal | last1=Furman | first1=David | last2=Kosloff | first2=Ronnie | last3=Dubnikova | first3=Faina | last4=Zybin | first4=Sergey V. | last5=Goddard | first5=William A. | last6=Rom | first6=Naomi | last7=Hirshberg | first7=Barak | last8=Zeiri | first8=Yehuda | title=Decomposition of Condensed Phase Energetic Materials: Interplay between Uni- and Bimolecular Mechanisms | journal=Journal of the American Chemical Society | publisher=American Chemical Society (ACS) | volume=136 | issue=11 | date=6 March 2014 | issn=0002-7863 | doi=10.1021/ja410020f | pages=4192–4200| pmid=24495109 | url=https://resolver.caltech.edu/CaltechAUTHORS:20140428-125540687 }}</ref> 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.{{Cn|date=January 2021}}

TNT can be detonated with a high velocity initiator or by efficient concussion.<ref>''[[Merck Index]]'', 13th Edition, '''9801'''</ref> 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.<ref>{{Cite web |title=Figure of Insensitivity {{!}} 1 Publications {{!}} 12 Citations {{!}} Top Authors {{!}} Related Topics |url=https://typeset.io/topics/figure-of-insensitivity-2tdtuknh |access-date=2023-07-21 |website=SciSpace - Topic |language=en |archive-date=2023-07-21 |archive-url=https://web.archive.org/web/20230721190324/https://typeset.io/topics/figure-of-insensitivity-2tdtuknh |url-status=dead }}</ref>

== Energy content ==

{{See also|TNT equivalent}}

[[File:British 20 mm Oerlikon shell diagrams.jpg|thumb|Cross-sectional view of [[Oerlikon 20 mm cannon]] shells (dating from {{Circa|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 [[NIST]] to define the equivalent is 4.184 [[gigajoule|GJ]]/t.<ref>{{Cite web |url=https://www.nist.gov/physical-measurement-laboratory/nist-guide-si-appendix-b8 |title=Guide for the Use of the International System of Units (SI) |date=2008 |access-date=2024-03-25 }}</ref>

For safety assessments, it has been stated that the detonation of TNT, depending on circumstances, can release 2.673–6.702 GJ/t.<ref>{{cite web |url=https://hal.archives-ouvertes.fr/hal-00629253/document |title=Blast effects of external explosions (Section 4.8 Limitations of the TNT equivalent method) |page=16 |year=2011 |archive-url=https://web.archive.org/web/20160810225249/http://hal.archives-ouvertes.fr/hal-00629253/document |archive-date=2016-08-10}}</ref>

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.<ref name=babrauskas>{{cite book |last1=Babrauskas |first1=Vytenis |title=Ignition Handbook |year=2003 |publisher=Fire Science Publishers/Society of Fire Protection Engineers |location=Issaquah, WA |isbn=978-0-9728111-3-2 |page=453}}</ref>

For comparison, [[gunpowder]] contains 3 MJ/kg, [[dynamite]] contains 7.5 MJ/kg, and [[gasoline]] contains 47.2 MJ/kg (though gasoline requires an [[oxidizing agent|oxidant]], so an optimized gasoline and O₂ mixture contains 10.4 MJ/kg).{{Cn|date=January 2021}}

== Detection ==

Various methods can be used to detect TNT, including optical and [[Electrochemical gas sensor|electrochemical]] sensors and [[Explosive-sniffing dog|explosive-sniffing dogs.]] In 2013, researchers from the [[Indian Institutes of Technology]] using [[Noble metal|noble-metal]] quantum clusters could detect TNT at the sub-[[zeptomolar]] (10⁻¹⁸ mol/m³) level.<ref>{{cite journal|last=Grad|first=Paul|title=Quantum clusters serve as ultra-sensitive detectors|journal=Chemical Engineering|date=April 2013|url=http://www.chemengonline.com/quantum-clusters-serve-as-ultra-sensitive-detectors/}}</ref>

== 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 [[World War I|First World War]], female munition workers who handled the chemical found that their skin turned bright yellow, which resulted in their acquiring the nickname "[[canary girls]]" or simply "canaries".<ref>{{Cite news|date=2017-05-20|title=The Canary Girls: The workers the war turned yellow|language=en-GB|work=BBC News|url=https://www.bbc.com/news/uk-england-39434504|access-date=2021-02-07}}</ref>

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]].<ref>[http://www.atsdr.cdc.gov/toxprofiles/tp81.pdf Toxicological Profile for 2,4,6-Trinitrotoluene]. atsdr.cdc.gov</ref> 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).<ref>{{Cite web|url=https://pubchem.ncbi.nlm.nih.gov/compound/8376 |website=www.nlm.nih.gov|title=2,4,6-Trinitrotoluene}}</ref> Consumption of TNT produces red [[urine]] through the presence of breakdown products and not blood as sometimes believed.<ref>{{Cite web | publisher = [[Agency for Toxic Substances and Disease Registry]] | title=2,4,6-Trinitrotoluene|url=http://www.atsdr.cdc.gov/ToxProfiles/tp81-c2.pdf | access-date = 2010-05-17}}</ref>

Some military testing grounds are contaminated with [[wastewater]] from munitions programs, including contamination of surface and [[groundwater|subsurface waters]] which may be colored pink because of the presence of TNT. Such contamination, called "pink water", may be difficult and expensive to [[Environmental remediation|remedy]].{{Cn|date=January 2021}}

TNT is prone to [[exudation]] of [[dinitrotoluene]]s and other isomers of trinitrotoluene when [[shell (projectile)|projectiles]] containing TNT are stored at higher temperatures in warmer climates. Exudation of impurities leads to formation of pores and cracks (which in turn cause increased shock sensitivity). Migration of the exudated liquid into the [[Fuze (explosives)|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.<ref>{{cite book|url=https://books.google.com/books?id=9tIQDn2uZz4C&pg=PA11|title=The Chemistry of Explosives|date=2004|publisher=Royal Society of Chemistry|isbn=978-0-85404-640-9|pages=11–|author=Akhavan J}}</ref> [[Calcium silicate]] is mixed with TNT to mitigate the tendency towards exudation.<ref>{{cite web|url=http://www.islandgroup.com/military/explosives_additives.php|title=Explosive & Propellant Additives|work=islandgroup.com|access-date=2014-06-07|archive-date=2016-03-04|archive-url=https://web.archive.org/web/20160304032754/http://www.islandgroup.com/military/explosives_additives.php|url-status=dead}}</ref>

===Pink and red water===

{{For|the author|Daniel Pinkwater}}

'''Pink water''' and '''red water''' are two distinct types of [[wastewater]] related to trinitrotoluene.<ref>{{cite book|last=Yinon|first=Jehuda|title=Toxicity and metabolism of explosives|year=1990|publisher=CRC Press|isbn=0-8493-5128-6|pages=176|url=https://books.google.com/books?id=BD3c7FN4x5YC&q=%22red+water%22+tnt&pg=PA39}}</ref> Pink water is produced from equipment washing processes after [[munitions]] filling or [[demilitarization]] operations,<ref name="NDCEE_1995">{{cite report |author=National Defense Center for Environmental Excellence |title=Pink Water Treatment Options |url= https://apps.dtic.mil/sti/pdfs/ADA295802.pdf |publisher= U.S. Army Environmental Center |access-date=2024-04-25}}</ref><ref name="Deuren_2002"/> and as such is generally saturated with the maximum amount of TNT that will dissolve in water (about 150 parts per million (ppm).) However it has an indefinite composition that depends on the exact process; in particular, it may also contain [[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 [[Sulfonic acid#Sulfonic acids|sulfonated]] [[Nitro_compound#Aromatic_nitro_compounds|nitroaromatics]].{{Cn|date=January 2021}}

Pink and red water are colorless at the time of generation; the color is produced by [[photolysis|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.<ref name="Deuren_2002">{{cite report |last1=Van Deuren |first1=Julie |last2=Lloyd |first2=Teressa |last3=Chhetry |first3=Shobha |last4=Liou |first4=Raycham |last5=Peck |first5=James |date=January 2002 |title=Remediation Technologies Screening Matrix and Reference Guide |edition=4 |url=https://www.frtr.gov/matrix2/section2/2_10_3.html |publisher= U.S. Army Environmental Center |access-date=2024-04-25}}</ref><ref name="Burlinson_1973">{{cite report |last1=Burlinson |first1=Nicholas E. |last2=Kaplan |first2=Lloyd A. |last3=Adams |first3=Charles E. |date=1973-10-03 |title=Photochemistry of TNT: Investigation of the "Pink Water" Problem |url=https://apps.dtic.mil/sti/pdfs/AD0769670.pdf |publisher= U.S. Army Environmental Center |access-date=2024-04-25}}</ref>

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.{{Cn|date=January 2021}}

== 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]].<ref>{{cite report |url=https://www.environment.gov.au/system/files/resources/bc0e52ba-8f78-4ce1-83b4-4910f4a1f0e9/files/hazardous-waste-impacts.pdf |title=The health and environmental impacts of hazardous wastes: Impact Profiles |author=Ascend Waste and Environment |website=awe.gov.au |date=7 June 2015 |access-date=22 April 2022}}</ref>

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.<ref name="Esteve-Nunez_2001">{{cite journal|year=2001|title=Biological degradation of 2,4,6-trinitrotoluene|journal=Microbiol. Mol. Biol. Rev.|volume=65|issue=3|pages=335–52, table of contents|doi=10.1128/MMBR.65.3.335-352.2001|pmc=99030|pmid=11527999|vauthors=Esteve-Núñez A, Caballero A, Ramos JL}}</ref> 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.<ref name="Ayoub_2010">{{cite journal|year=2010|title=Application of advanced oxidation processes for TNT removal: A review|journal=J. Hazard. Mater.|volume=178|issue=1–3|pages=10–28|doi=10.1016/j.jhazmat.2010.02.042|pmid=20347218|vauthors=Ayoub K, van Hullebusch ED, Cassir M, Bermond A}}</ref>

=== Aqueous solubility ===

[[Dissolution (chemistry)|Dissolution]] is a measure of the rate that solid TNT in contact with water is dissolved. The relatively low [[Solubility|aqueous solubility]] of TNT causes solid particles to be continuously released to the environment over extended periods of time.<ref name="Pichtel_2012">{{cite journal|date=2012|title=Distribution and Fate of Military Explosives and Propellants in Soil: A Review|journal=Applied and Environmental Soil Science|volume=2012|pages=1–33|doi=10.1155/2012/617236|author=Pichte J|doi-access=free}}</ref> 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.<ref name="pmid15757688">{{cite journal|year=2005|title=Comparison of environmental fate and transport process descriptors of explosives in saline and freshwater systems|journal=Mar. Pollut. Bull.|volume=50|issue=3|pages=247–51|doi=10.1016/j.marpolbul.2004.10.008|pmid=15757688|vauthors=Brannon JM, Price CB, Yost SL, Hayes C, Porter B|bibcode=2005MarPB..50..247B }}</ref> Because TNT is moderately soluble in water, it can migrate through subsurface soil, and cause [[groundwater]] contamination.<ref name="pmid12187997">{{cite journal|year=2002|title=Detection of explosives and their degradation products in soil environments|journal=J Chromatogr A|volume=963|issue=1–2|pages=411–8|doi=10.1016/S0021-9673(02)00553-8|pmid=12187997|vauthors=Halasz A, Groom C, Zhou E, Paquet L, Beaulieu C, Deschamps S, Corriveau A, Thiboutot S, Ampleman G, Dubois C, Hawari J}}</ref>

=== 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.<ref name="pmid19329139">{{cite journal|year=2009|title=A time series investigation of the stability of nitramine and nitroaromatic explosives in surface water samples at ambient temperature |journal=Chemosphere |volume=76 |issue=1 |pages=1–8 |doi=10.1016/j.chemosphere.2009.02.050 |pmid=19329139 |vauthors=Douglas TA, Johnson L, Walsh M, Collins C |bibcode=2009Chmsp..76....1D|url=https://zenodo.org/record/851720}}</ref> 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.<ref name="Haderlein_1996">{{cite journal|date=January 1996|title=Specific Adsorption of Nitroaromatic Explosives and Pesticides to Clay Minerals|journal=Environmental Science & Technology|volume=30|issue=2|pages=612–622|doi=10.1021/es9503701|vauthors=Haderlein SB, Weissmahr KW, Schwarzenbach RP|bibcode=1996EnST...30..612H}}</ref> This means that TNT has a one- to tenfold tendency to adhere to soil particulates than not when introduced into the soil.<ref name = "Pichtel_2012"/> [[Hydrogen bonding]] and [[ion exchange]] are two suggested mechanisms of adsorption between the nitro functional groups and soil colloids.

The number of [[functional group]]s 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.<ref name = "Pichtel_2012"/> Lower adsorption coefficients for 2,6-DNT compared to 2,4-DNT can be attributed to the [[Steric effects|steric]] hindrance of the NO₂ group in the [[Arene substitution pattern|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.<ref name="Pennington_2002">{{cite journal|date=February 2002|title=Environmental fate of explosives|journal=Thermochimica Acta|volume=384|issue=1–2|pages=163–172|doi=10.1016/S0040-6031(01)00801-2|vauthors=Pennington JC, Brannon JM}}</ref>

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."<ref name = "Pennington_2002"/> Thus, the mobility of TNT and its transformation products are dependent on the characteristics of the sorbent.<ref name = "Pennington_2002"/> The mobility of TNT in groundwater and soil has been extrapolated from "sorption and desorption [[Isothermal process|isotherm models]] determined with [[humic acids]], in aquifer sediments, and soils".<ref name = "Pennington_2002"/> From these models, it is predicted that TNT has a low retention and transports readily in the environment.<ref name = "Esteve-Nunez_2001"/>

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.<ref name = "Pichtel_2012"/>

=== 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]], [[ferrous|Fe²⁺]], or microbial communities, both oxic and anoxic and photochemical degradation.{{Cn|date=January 2021}}

Soils with high clay contents or small particle sizes and high [[Total organic carbon|total organic carbon content]] have been shown to promote TNT transformation. Possible TNT transformations include [[Reduction reaction|reduction]] of one, two, or three nitro-moieties to amines and coupling of amino transformation products to form [[dimer (chemistry)|dimer]]s. 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.{{Cn|date=January 2021}}

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.<ref name = "Pennington_2002"/>

[[Photolysis]] is a major process that impacts the transformation of energetic compounds. The alteration of a molecule in photolysis occurs by direct absorption of light energy or by the transfer of energy from a photosensitized compound. [[Phototransformation]] of TNT "results in the formation of [[nitrobenzene]]s, [[benzaldehyde]]s, azodicarboxylic acids, and [[nitrophenol]]s, as a result of the [[oxidation]] of [[methyl group]]s, reduction of [[nitro compound|nitro groups]], and dimer formation."<ref name = "Pichtel_2012"/>

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.<ref name = "Pennington_2002"/>

=== 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.<ref name="pmid11131384">{{cite journal|year=2000|title=Microbial degradation of explosives: biotransformation versus mineralization|journal=Appl. Microbiol. Biotechnol.|volume=54|issue=5|pages=605–18|doi=10.1007/s002530000445|pmid=11131384|vauthors=Hawari J, Beaudet S, Halasz A, Thiboutot S, Ampleman G|s2cid=22362850}}</ref> Both wild and transgenic plants can [[Phytoremediation|phytoremediate]] explosives from soil and water.<ref name="pmid22996005">{{cite journal|year=2012|title=Phytoremediation of explosives (TNT, RDX, HMX) by wild-type and transgenic plants|journal=J. Environ. Manage.|volume=113|pages=85–92|doi=10.1016/j.jenvman.2012.08.016|pmid=22996005|vauthors=Panz K, Miksch K}}</ref>

== See also ==

<!---♦♦♦ Please keep the list in alphabetical order ♦♦♦--->

* [[Dynamite]]

* [[Environmental fate of TNT]]

* [[IMX-101]]

* [[List of explosives used during World War II]]

* [[Phlegmatized]]

* [[RE factor]]

* [[Table of explosive detonation velocities]]

* [[TNT equivalent]]

* [[Webster's test]]

== References ==

{{Reflist|35em}}

== External links ==

{{commons category|Trinitrotoluene}}

* [http://www.periodicvideos.com/videos/mv_dynamite.htm Dynamite and TNT] at ''[[The Periodic Table of Videos]]'' (University of Nottingham)

* [https://www.youtube.com/watch?v=vb3y6m-buco "TNT" on YouTube] showing the shockwave and typical black smoke cloud from detonation of 160 kilograms of pure TNT

* [https://www.cdc.gov/niosh/npg/npgd0641.html CDC – NIOSH Pocket Guide to Chemical Hazards]

{{Authority control}}

[[Category:Trinitrotoluene| ]]

[[Category:Immunotoxins]]

[[Category:2-Tolyl compounds]]

[[Category:4-Tolyl compounds]]

[[Category:Biodegradation]]