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'''Pentaerythritol tetranitrate''' ('''PETN'''), also known as '''PENT''', '''PENTA''', '''TEN''', '''corpent''', '''penthrite''' (or—rarely and primarily in German—as '''nitropenta'''), is the [[nitrate]] [[ester]] of [[pentaerythritol]], and is structurally very similar to [[nitroglycerin]]. Penta refers to the five [[carbon atom]]s of the [[neopentane]] skeleton.
'''Pentaerythritol tetranitrate''' ('''PETN'''), also known as '''PENT''', '''PENTA''', '''TEN''', '''corpent''', '''penthrite''' (or—rarely and primarily in German—as '''nitropenta'''), is the [[nitrate]] [[ester]] of [[pentaerythritol]], and is structurally very similar to [[nitroglycerin]]. Penta refers to the five [[carbon atom]]s of the [[neopentane]] skeleton.
PETN is best known as an explosive. It is one of the most powerful [[explosive material|high explosives]] known, with a [[relative effectiveness factor]] of 1.66.<ref name="urlPETN [Pentaerythritol tetranitrate]">{{cite web |url=http://www.globalsecurity.org/military/systems/munitions/explosives-nitrate-petn.htm |title=PETN (Pentaerythritol tetranitrate) |accessdate=March 29, 2010}}</ref>
PETN is best known as an explosive. It is one of the most powerful [[explosive material|high explosives]] known, with a [[relative effectiveness factor]] of 1.66.
PETN mixed with a [[plasticizer]] forms a [[plastic explosive]].<ref>{{cite encyclopedia | title = Explosives | encyclopedia = A dictionary of military history and the art of war | author = John Childs | url = http://books.google.com/books?id=nEQ7FUAdmc8C&pg=PA231 | format = [[Google Books]] extract | isbn = 978-0-631-16848-5 | year = 1994}}</ref> As a mixture with [[RDX]] and other minor additives, it forms another plastic explosive called [[Semtex]] as well. The compound was discovered in the bombs used by the 2001 [[Shoe Bomber]], in the [[2009 Christmas Day bomb plot]], and in the [[2010 cargo plane bomb plot]].<ref name="scientificamerican1"/> On 7 September 2011, a bomb suspected to have used PETN exploded near the [[High Court of Delhi]] in India claiming 13 lives and injuring more than 70.<ref name=delhiblast>{{cite news|url=http://www.thehindu.com/news/national/article2432945.ece?homepage=true|title=Nationwide alert as NIA takes up probe | location=Chennai, India | work=The Hindu|first=Vinay|last=Kumar|date=September 7, 2011}}</ref>
PETN mixed with a [[plasticizer]] forms a [[plastic explosive]]. As a mixture with [[RDX]] and other minor additives, it forms another plastic explosive called [[Semtex]] as well. The compound was discovered in the bombs used by the 2001 [[Shoe Bomber]], in the [[2009 Christmas Day bomb plot]], and in the [[2010 cargo plane bomb plot]]. On 7 September 2011, a bomb suspected to have used PETN exploded near the [[High Court of Delhi]] in India claiming 13 lives and injuring more than 70.
It is also used as a [[Vasodilation|vasodilator]] drug to treat certain heart conditions, such as for management of [[angina]].<ref name = newdrugs>{{cite journal | pmc = 1831125 | title = New Drugs | journal = [[Can Med Assoc J]] | year = 1959 | volume = 80 | pages = 997–998 | pmid=20325960}}</ref><ref name = ebadi>{{cite book | title = CRC desk reference of clinical pharmacology | page = 383 | author = Manuchair S. Ebadi | year = 1998 | isbn = 978-0-8493-9683-0 | url = http://books.google.com/books?id=-EAxShTKfGAC&pg=PA383 | format = [[Google Books]] excerpt}}</ref>
It is also used as a [[Vasodilation|vasodilator]] drug to treat certain heart conditions, such as for management of [[angina]].<ref name = newdrugs>{{cite journal | pmc = 1831125 | title = New Drugs | journal = [[Can Med Assoc J]] | year = 1959 | volume = 80 | pages = 997–998 | pmid=20325960}}</ref><ref name = ebadi>{{cite book | title = CRC desk reference of clinical pharmacology | page = 383 | author = Manuchair S. Ebadi | year = 1998 | isbn = 978-0-8493-9683-0 | url = http://books.google.com/books?id=-EAxShTKfGAC&pg=PA383 | format = [[Google Books]] excerpt}}</ref>
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==Properties==
==Properties==
PETN is practically [[solubility|insoluble]] in water (0.01 g/100 ml at 50 °C), weakly soluble in common nonpolar [[solvent]]s such as [[Aliphatic compound|aliphatic hydrocarbon]]s (like gasoline) or [[Carbon tetrachloride|tetrachloromethane]], but soluble in some other organic solvents, particularly in [[acetone]] (about 15 g/100 g of the solution at 20 °C, 55 g/100 g at 60 °C) and [[dimethylformamide]] (40 g/100 g of the solution at 40 °C, 70 g/100 g at 70 °C). PETN forms [[eutectic system|eutectic]] mixtures with some liquid or molten [[aromaticity|aromatic]] [[nitro compound]]s, ''e.g.'' [[trinitrotoluene]] (TNT) or [[tetryl]]. Due to its highly symmetrical structure, PETN is resistant to attack by many chemical [[reagent]]s; it does not [[hydrolysis|hydrolyze]] in water at room temperature or in weaker [[alkalinity|alkaline]] [[aqueous solution]]s. Water at 100 °C or above causes [[hydrolysis]] to dinitrate; presence of 0.1% [[nitric acid]] accelerates the reaction. Addition of TNT and other aromatic [[Nitro compound|nitro]] derivatives lowers [[thermal stability]] of PETN.{{Citation needed|date=November 2010}}
PETN is practically [[solubility|insoluble]] in water (0.01 g/100 ml at 50 °C), weakly soluble in common nonpolar [[solvent]]s such as [[Aliphatic compound|aliphatic hydrocarbon]]s (like gasoline) or [[Carbon tetrachloride|tetrachloromethane]], but soluble in some other organic solvents, particularly in [[acetone]] (about 15 g/100 g of the solution at 20 °C, 55 g/100 g at 60 °C) and [[dimethylformamide]] (40 g/100 g of the solution at 40 °C, 70 g/100 g at 70 °C). PETN forms [[eutectic system|eutectic]] mixtures with some liquid or molten [[aromaticity|aromatic]] [[nitro compound]]s, ''e.g.'' [[trinitrotoluene]] (TNT) or [[tetryl]]. Due to its highly symmetrical structure, PETN is resistant to attack by many chemical [[reagent]]s; it does not [[hydrolysis|hydrolyze]] in water at room temperature or in weaker [[alkalinity|alkaline]] [[aqueous solution]]s. Water at 100 °C or above causes [[hydrolysis]] to dinitrate; presence of 0.1% [[nitric acid]] accelerates the reaction. Addition of TNT and other aromatic [[Nitro compound|nitro]] derivatives lowers [[thermal stability]] of PETN.
The [[chemical stability]] of PETN is of interest, because of the use of PETN in aging stockpiles of weapons. A review has been published.<ref>{{Cite journal | title = Aging of Pentaerythritol Tetranitrate (PETN) | url = https://e-reports-ext.llnl.gov/pdf/372573.pdf | author = M. F. Foltz | publisher = [[Lawrence Livermore National Laboratory]] | postscript = <!-- Bot inserted parameter. Either remove it; or change its value to "." for the cite to end in a ".", as necessary. -->{{inconsistent citations}}}}</ref> [[Neutron radiation]] degrades PETN, producing [[carbon dioxide]] and some pentaerythritol dinitrate and [[Nitrate|trinitrate]]. [[Gamma radiation]] increases the [[thermal decomposition]] sensitivity of PETN, lowers melting point by few degrees Celsius, and causes swelling of the samples. Like other nitrate esters, the primary [[Chemical decomposition|degradation]] mechanism is the loss of [[nitrogen dioxide]]; this reaction is [[autocatalytic]].{{Citation needed|date=November 2010}}. Studies were performed on [[thermal decomposition]] of PETN.<ref>[http://www.intdetsymp.org/detsymp2002/PaperSubmit/FinalManuscript/pdf/German-258.pdf Thermal decomposition of PENT and HMX over a wide temperature range] by V.N. German ''et al.''</ref>
The [[chemical stability]] of PETN is of interest, because of the use of PETN in aging stockpiles of weapons. A review has been published. [[Neutron radiation]] degrades PETN, producing [[carbon dioxide]] and some pentaerythritol dinitrate and [[Nitrate|trinitrate]]. [[Gamma radiation]] increases the [[thermal decomposition]] sensitivity of PETN, lowers melting point by few degrees Celsius, and causes swelling of the samples. Like other nitrate esters, the primary [[Chemical decomposition|degradation]] mechanism is the loss of [[nitrogen dioxide]]; this reaction is [[autocatalytic]]. Studies were performed on [[thermal decomposition]] of PETN.
In the environment, PETN undergoes [[biodegradation]]. Some bacteria denitrate PETN to trinitrate and then dinitrate, which is then further degraded.{{Citation needed|date=November 2010}} PETN has low [[Volatility (chemistry)|volatility]] and low solubility in water, and therefore has low [[bioavailability]] for most organisms. Its [[toxicity]] is relatively low, and its [[transdermal]] absorption also seems to be low.<ref name=army1/> It poses a threat for aquatic [[organism]]s. It can be degraded to pentaerythritol by [[iron]] metal.<ref>{{cite journal|doi=10.1021/es7029703|title=Degradation of Pentaerythritol Tetranitrate (PETN) by Granular Iron|author=Li Zhuang, Lai Gui and Robert W. Gillham|journal=[[Environ. Sci. Technol.]]|year=2008|volume=42|page=4534|pmid=18605582}}</ref>
In the environment, PETN undergoes [[biodegradation]]. Some bacteria denitrate PETN to trinitrate and then dinitrate, which is then further degraded. PETN has low [[Volatility (chemistry)|volatility]] and low solubility in water, and therefore has low [[bioavailability]] for most organisms. Its [[toxicity]] is relatively low, and its [[transdermal]] absorption also seems to be low. It poses a threat for aquatic [[organism]]s. It can be degraded to pentaerythritol by [[iron]] metal.<ref>{{cite journal|doi=10.1021/es7029703|title=Degradation of Pentaerythritol Tetranitrate (PETN) by Granular Iron|author=Li Zhuang, Lai Gui and Robert W. Gillham|journal=[[Environ. Sci. Technol.]]|year=2008|volume=42|page=4534|pmid=18605582}}</ref>
==Production==
==Production==
Production is by the reaction of [[pentaerythritol]] with concentrated [[nitric acid]] to form a precipitate which can be recrystallized from acetone to give processable crystals.<ref name = Ullmann>{{Ullmann | doi = 10.1002/14356007.a10_143.pub2 | title = Explosives | author = Jacques Boileau, Claude Fauquignon, Bernard Hueber, Hans H. Meyer}}</ref>
Production is by the reaction of [[pentaerythritol]] with concentrated [[nitric acid]] to form a precipitate which can be recrystallized from acetone to give processable crystals.
PETN is manufactured by numerous manufacturers as a powder about the consistency of fine popcorn salt, or together with [[nitrocellulose]] and [[plasticizer]] as thin plasticized sheets (e.g. [[Primasheet]] 1000 or [[Detasheet]]). PETN residues are easily detectable in hair of people handling it.<ref>Winslow, Ron. (2009-12-29) [http://online.wsj.com/article/SB126195987401406861.html A Primer in PETN – WSJ.com]. Online.wsj.com. Retrieved on 2010-02-08.</ref> The highest residue retention is on black hair; some residues remain present even after washing.<ref>{{cite journal | last1 = Oxley | first1 = Jimmie C. | last2 = Smith | first2 = James L. | last3 = Kirschenbaum | first3 = Louis J. | last4 = Shinde | first4 = Kajal. P. | last5 = Marimganti | first5 = Suvarna | title = Accumulation of Explosives in Hair | journal = Journal of Forensic Sciences | volume = 50 | page = 1 | year = 2005 | doi = 10.1520/JFS2004545}}</ref><ref name="latimes.com">{{cite news| url=http://www.latimes.com/news/nationworld/nation/wire/sc-dc-1124-petn-20101123,0,2000499.story | deadurl=yes}} {{Dead link|date=February 2011|bot=RjwilmsiBot}}</ref>
PETN is manufactured by numerous manufacturers as a powder about the consistency of fine popcorn salt, or together with [[nitrocellulose]] and [[plasticizer]] as thin plasticized sheets (e.g. [[Primasheet]] 1000 or [[Detasheet]]). PETN residues are easily detectable in hair of people handling it.<ref>Winslow, Ron. (2009-12-29) [http://online.wsj.com/article/SB126195987401406861.html A Primer in PETN – WSJ.com]. Online.wsj.com. Retrieved on 2010-02-08.</ref> The highest residue retention is on black hair; some residues remain present even after washing.<ref>{{cite journal | last1 = Oxley | first1 = Jimmie C. | last2 = Smith | first2 = James L. | last3 = Kirschenbaum | first3 = Louis J. | last4 = Shinde | first4 = Kajal. P. | last5 = Marimganti | first5 = Suvarna | title = Accumulation of Explosives in Hair | journal = Journal of Forensic Sciences | volume = 50 | page = 1 | year = 2005 | doi = 10.1520/JFS2004545}}</ref><ref name="latimes.com">{{cite news| url=http://www.latimes.com/news/nationworld/nation/wire/sc-dc-1124-petn-20101123,0,2000499.story | deadurl=yes}} {{Dead link|date=February 2011|bot=RjwilmsiBot}}</ref>
==Explosive Use==
The most common use of PETN is as an explosive with high [[brisance]]. It is more difficult to detonate than [[primary explosive]]s, so dropping or igniting it will typically not cause an explosion (at [[atmospheric pressure]] it is difficult to ignite and burns relatively slowly), but is more sensitive to shock and friction than other secondary explosives such as TNT or [[tetryl]].<ref name = Ullmann/><ref name=nyt>{{Cite news|url=http://www.nytimes.com/2009/12/28/us/28explosives.html?ref=us|title=Explosive on Flight 253 Is Among Most Powerful |newspaper=The New York Times|date=December 27, 2009|author=Kenneth Chang}}</ref> Under certain conditions a [[deflagration to detonation transition]] can occur.
It is rarely used alone, but primarily used in [[explosive booster|booster]] and [[burst charge|bursting charges]] of small [[caliber]] [[ammunition]], in upper charges of [[detonator]]s in some [[land mine]]s and shells, and as the explosive core of [[detonation cord]].<ref name="urlwww.dynonobel.com">{{cite web|url = http://www.dynonobel.com/files/2010/04/Primacord.pdf |title = Primacord Technical Information|publisher = Dyno Nobel|accessdate = April 22, 2009}} {{Dead link|date=October 2010|bot=H3llBot}}</ref> PETN is the least stable of the common military explosives, but can be stored without significant deterioration for longer than [[nitroglycerin]] or [[nitrocellulose]].<ref>[http://www.britannica.com/EBchecked/topic/454067/PETN PETN (chemical compound) – Britannica Online Encyclopedia]. Britannica.com. Retrieved on 2010-02-08.</ref>
During [[World War II]], PETN was most importantly used in [[exploding-bridgewire detonator]]s for the atomic bombs. These exploding-bridgewire detonators gave more precise detonation, compared with [[primacord]]. PETN was used for these detonators because it was safer than primary explosives like [[lead azide]]: while it was sensitive, it would not detonate below a threshold amount of energy.<ref>{{cite book | title = A Technical History of Los Alamos During the Oppenheimer Years, 1943–1945 | author = Lillian Hoddeson, Paul W. Henriksen, Roger A. Meade, Catherine L. Westfall, Gordon Baym, Richard Hewlett, Alison Kerr, Robert Penneman, Leslie Redman, Robert Seidel | year = 2004 | pages = 164–173 | url = http://books.google.com/books?id=KoTve97yYB8C&pg=PA164 | format = [[Google Books]] excerpt | isbn = 978-0-521-54117-6}}</ref> Exploding bridgewires containing PETN remain used in current nuclear weapons. In spark detonators, PETN is used to avoid the need for primary explosives; the energy needed for a successful direct initiation of PETN by an [[electric spark]] ranges between 10–60 mJ.
Its basic explosion characteristics are:
* Explosion energy: 5810 kJ/kg (1390 kcal/kg), so 1 kg of PETN has the energy of 1.24 kg TNT.
* [[Detonation velocity]]: 8350 m/s (1.73 g/cm<sup>3</sup>), 7910 m/s (1.62 g/cm<sup>3</sup>), 7420 m/s (1.5 g/cm<sup>3</sup>), 8500 m/s (pressed in a steel tube)
* [[Trauzl lead block test]]: 523 cm<sup>3</sup> (other values: 500 cm<sup>3</sup> when sealed with sand, or 560 cm<sup>3</sup> when sealed with water)
* Critical diameter (minimal diameter of a rod that can sustain detonation propagation): 0.9 mm for PETN at 1 g/cm<sup>3</sup>, smaller for higher densities (other value: 1.5 mm)
===In mixtures===
PETN is used in a number of compositions. It is a major ingredient of the [[Semtex]] [[plastic explosive]]. It is also used as a component of [[pentolite]], a 50/50 blend with TNT; a [[shaped charge]] of {{convert|8|oz|kg}} of pentolite, used in the [[bazooka|M9A1 (bazooka)]] rockets, can penetrate up to {{convert|5|in|mm}} of armor.{{Citation needed|date=November 2010}} The XTX8003 extrudable explosive, used in the [[W68]] and [[W76]] nuclear warheads, is a mixture of 80% PETN and 20% of Sylgard 182, a [[silicone rubber]].<ref>[http://www.osti.gov/bridge/servlets/purl/650196-rV1bU0/webviewable/650196.pdf Information Bridge: DOE Scientific and Technical Information – Sponsored by OSTI]. Osti.gov (2009-11-23). Retrieved on 2010-02-08.</ref> It is often [[phlegmatized]] by addition of 5–40% of [[wax]], or by polymers (producing [[polymer-bonded explosive]]s); in this form it is used in some cannon shells up to [[30 mm caliber]], though unsuitable for higher calibers. <!-- why? --> It is also used as a component of some gun [[propellant]]s and [[solid rocket propellant]]s. Nonphlegmatized PETN is stored and handled with approximately 10% water content. PETN alone cannot be [[casting|cast]] as it explosively decomposes slightly above its melting point, but it can be mixed with other explosives to form castable mixtures.
PETN can be initiated by a [[laser]].<ref>{{cite journal | last1 = Tarzhanov | first1 = V. I. | last2 = Zinchenko | first2 = A. D. | last3 = Sdobnov | first3 = V. I. | last4 = Tokarev | first4 = B. B. | last5 = Pogrebov | first5 = A. I. | last6 = Volkova | first6 = A. A. | title = Laser initiation of PETN | journal = Combustion, Explosion, and Shock Waves | volume = 32 | page = 454 | year = 1996 | doi = 10.1007/BF01998499}}</ref> A pulse with duration of 25 nanoseconds and 0.5–4.2 joules of energy from a [[Q-switching|Q-switched]] [[ruby laser]] can initiate detonation of a PETN surface coated with a 100 nm thick aluminium layer in less than half microsecond.{{Citation needed|date=November 2010}}
PETN has been replaced in many applications by [[RDX]], which is thermally more stable and has longer [[shelf life]].<ref>US Army – Encyclopedia of Explosives and Related Items, vol.8</ref> PETN can be used in some [[ram accelerator]] types.<ref>[http://fluid.ippt.gov.pl/ictam04/CD_ICTAM04/FM3/12843/FM3_12843.pdf Simulation of ram accelerator with PETN layer], Arkadiusz Kobiera and Piotr Wolanski, XXI ICTAM, 15–21 August 2004, Warsaw, Poland</ref> Replacement of the central carbon atom with [[silicon]] produces Si-PETN, which is extremely sensitive.<ref>{{cite journal|url=http://www.wag.caltech.edu/publications/sup/pdf/806.pdf|title=Explanation of the Colossal Detonation Sensitivity of Silicon Pentaerythritol Tetranitrate (Si-PETN) Explosive|author=Wei-Guang Liu ''et al.''|journal=J. Am. Chem. Soc.|year=2009|volume=131|page=7490|doi=10.1021/ja809725p|pmid=19489634}}</ref><ref>[http://comporgchem.com/blog/?p=258 Computational Organic Chemistry » Si-PETN sensitivity explained]. Comporgchem.com (2009-07-20). Retrieved on 2010-02-08.</ref>
===Terrorist Use===
{{Main|Shoe Bomber|2009 Christmas Day bomb plot|2010 cargo plane bomb plot}}
In 1983, the "Maison de France" house in Berlin was brought to a near-total collapse by the detonation of {{convert|24|kg|lb}} of PETN by terrorist [[Johannes Weinrich]].<ref>{{cite web|url=http://www.spiegel.de/panorama/0,1518,56218,00.html |title=Article detailing attack on Maison de France in Berlin (German) |publisher=Spiegel.de |date=December 13, 1999 |accessdate=November 4, 2010}}</ref>
In 1999, [[Alfred Heinz Reumayr]] used PETN as the main charge for his fourteen [[improvised explosive device]]s that he constructed in a thwarted attempt to damage the [[Trans-Alaska Pipeline System]].
In 2001, [[al-Qaeda]] member [[Richard Reid (shoe bomber)|Richard Reid]], the "Shoe Bomber", used PETN in the sole of his sneaker in his unsuccessful attempt to blow up [[American Airlines Flight 63]] from Paris to Miami.<ref name="latimes.com"/><ref name="urlBBC News|AMERICAS|Shoe bomb suspect did not act alone">{{cite news|url = http://news.bbc.co.uk/2/hi/americas/1783237.stm|title = 'Shoe bomb suspect 'did not act alone'|date = January 25, 2002|publisher = BBC News|accessdate = April 22, 2009}}</ref> He had intended to use the solid [[triacetone triperoxide]] (TATP) as a detonator.<ref name=nyt/>
In 2009, PETN was used in an attempt by [[al-Qaeda in the Arabian Peninsula]] to murder the Saudi Arabian Deputy Minister of Interior Prince [[Muhammad bin Nayef]], by Saudi [[suicide bomber]] [[Abdullah Hassan Al Aseery|Abdullah Hassan al Asiri]]. The target survived and the bomber died in the blast. The PETN was hidden in the bomber's [[rectum]], which security experts described as a novel technique.<ref>{{cite web|url=http://homelandsecuritynewswire.com/saudi-suicide-bomber-hid-ied-his-anal-cavity|title=Saudi suicide bomber hid IED in his anal cavity|date=September 9, 2009|work=Homeland Security Newswire|postscript=<!-- Bot inserted parameter. Either remove it; or change its value to "." for the cite to end in a ".", as necessary. -->{{inconsistent citations}}}}</ref><ref>{{cite web|url=|author=Andrew England |title= Bomb clues point to Yemeni terrorists |publisher=Financial Times |date=November 1, 2010 |accessdate=November 1, 2010}}</ref><ref>{{cite news|author= |url=http://www.cbsnews.com/stories/2010/11/01/world/main7010288.shtml |title=Saudi Bombmaker Key Suspect in Yemen Plot |publisher=CBS News |date= November 1, 2010|accessdate=November 2, 2010}}</ref>
On December 25, 2009, PETN was found in the underwear of [[Umar Farouk Abdulmutallab]], the "Underwear bomber", a Nigerian with links to al-Qaeda in the Arabian Peninsula.<ref>
| title = Al Qaeda Claims Responsibility for Attempted Bombing of U.S. Plane
| date = December 28, 2009
| publisher = FOX News Network
| accessdate = December 29, 2009}}</ref>
According to U.S. law enforcement officials,<ref>{{cite news|url=http://big.assets.huffingtonpost.com/AbdumutallabCharges.pdf |title=Criminal Complaint |format=PDF |date= |accessdate=November 4, 2010 |work=[[The Huffington Post]]}}</ref> he had attempted to blow up [[Northwest Airlines Flight 253]] while approaching Detroit from Amsterdam.<ref name="urlABC News|AMERICAS|Investigators: Northwest Bomb Plot Planned by Al-Qaeda in Yemen">{{cite web|url = http://abcnews.go.com/Blotter/northwest-bomb-plot-planned-al-qaeda-yemen/story?id=9426085&page=1|title = 'Investigators: Northwest Bomb Plot Planned by al Qaeda in Yemen'|date = December 26, 2009|publisher = ABC News|accessdate = December 26, 2009}}</ref> Abdulmutallab had tried, unsuccessfully, to detonate approximately {{convert|80|g}} of PETN sewn into his underwear by adding liquid from a syringe;<ref>[http://www.washingtonpost.com/wp-dyn/content/article/2009/12/28/AR2009122800582.html Explosive in Detroit terror case could have blown hole in airplane, sources say] washingtonpost.com. Retrieved on 2010-02-08.</ref> however, only a small fire resulted.<ref name=nyt/>
In the al-Qaeda in the Arabian Peninsula October [[2010 cargo plane bomb plot]], two PETN-filled printer cartridges were found at [[East Midlands Airport]] and in [[Dubai]] on flights bound for the U.S. on an intelligence tip. Both packages contained sophisticated bombs concealed in computer [[Toner cartridge|printer cartridges]] filled with PETN.<ref name="scientificamerican1">{{cite web|last=Greenemeier |first=Larry |url=http://www.scientificamerican.com/article.cfm?id=aircraft-cargo-bomb-security |title=Exposing the Weakest Link: As Airline Passenger Security Tightens, Bombers Target Cargo Holds |publisher=Scientific American |date= |accessdate=November 3, 2010}}</ref><ref name="nytimes4">{{cite news| url=http://www.nytimes.com/2010/11/02/world/02terror.html?src=twrhp | work=The New York Times | first1=Scott | last1=Shane | first2=Robert F. | last2=Worth | title=Early Parcels Sent to U.S. Were Eyed as Dry Run | date=November 1, 2010}}</ref> The bomb found in England contained {{convert|400|g}} of PETN, and the one found in Dubai contained {{convert|300|g}} of PETN.<ref name="nytimes4"/> Hans Michels, professor of [[safety engineering]] at [[University College London]], told a newspaper that {{convert|6|g}} of PETN—"around 50 times less than was used—would be enough to blast a hole in a metal plate twice the thickness of an aircraft's skin".<ref>{{cite news |author= |url=http://indiatoday.intoday.in/site/Story/118746/World/parcel-bombs-could-rip-50-planes-in-half.html |title=Parcel bombs could rip 50 planes in half |work=[[India Today]] |date= |accessdate=November 3, 2010}}</ref> In contrast, according to an experiment conducted by a BBC documentary team designed to simulate Abdulmutallab's Christmas Day bombing, using a Boeing 747 airplane, even 80 grams of PETN was not sufficient to materially damage the airplane's fuselage.<ref>{{cite web|author=|url=http://news.discovery.com/tech/underwear-bomber-explosion-plane-test.html |title='Underwear Bomber' Could not have Blown Up Plane |publisher=[[Discovery Channel|Discovery]] |date=March 10, 2010|accessdate=November 16, 2010}}</ref>
===Detection===
In the wake of terrorist PETN bomb plots, an article in ''[[Scientific American]]'' noted that even if all cargo were screened, PETN is difficult to detect because it has a very low [[vapor pressure]] at room temperature, meaning very little of it gets into the air around the bomb, where it can be detected.<ref name="scientificamerican1"/> The ''[[Los Angeles Times]]'' noted in November 2010 that because of its more stable molecules, and lower vapor, it is more difficult to detect by bomb-sniffing dogs and the trace swabs then used by the U.S. [[Transportation Security Administration]].<ref name="latimes.com"/>
Many technologies can be used to detect PETN,<ref>Committee on the Review of Existing and Potential Standoff Explosives Detection Techniques, National Research Council, [http://www.nap.edu/openbook.php?record_id=10998&page=1 Existing and Potential Standoff Explosives Detection Techniques], National Academies Press, Washington, D.C., 2004, p. 77</ref> a number of which have been implemented in public screening applications, primarily for air travel. PETN is just one of a number of explosive chemicals typically of interest in that area, and it belongs to a family of common [[Nitro compound|nitrate-based explosive chemicals]] which can often be detected by the same tests.
One technology, detectors that test swabs wiped on passengers and their baggage for traces of explosives, is generally reserved for travelers who are thought to merit additional scrutiny. A second type of machine, whole-body imaging scanners, use radio-frequency [[electromagnetic wave]]s, low-intensity [[X-rays]], or T-rays of terahertz frequency to detect objects under clothing; these devices were of limited availability because of cost, privacy groups' opposition and industry concerns about bottlenecks.<ref>[http://www.washingtonpost.com/wp-dyn/content/article/2009/12/27/AR2009122702021.html "Equipment to detect explosives is available"]. ''[[The Washington Post]]''. Retrieved on 2010-02-08.</ref>
Both parcels in the 2010 cargo plane bomb plot were x-rayed without the bombs being spotted.<ref name="spiegel1"/> [[Qatar Airways]] said the PETN bomb "could not be detected by x-ray screening or trained [[sniffer dog]]s".<ref name="autogenerated1">{{cite news|url=http://www.bbc.co.uk/news/11658452 |title=Q&A: Air freight bomb plot |publisher=[[BBC News]] |date=October 30, 2010 |accessdate=November 3, 2010}}</ref> The [[Federal Criminal Police Office (Germany)|Bundeskriminalamt]] received copies of the Dubai x-rays, and an investigator said German staff would not have identified the bomb either.<ref name="spiegel1">{{cite news |url=http://www.spiegel.de/international/world/0,1518,726746,00.html |title=Foiled Parcel Plot: World Scrambles to Tighten Air Cargo Security |work=[[Der Spiegel]] |date= |accessdate=November 2, 2010}}</ref><ref name="aljazeera1">{{cite web |url=http://english.aljazeera.net/news/middleeast/2010/10/20101031144429122829.html |title=Passenger jets carried Dubai bomb |publisher=[[Al Jazeera]] |date= |accessdate=November 1, 2010}}</ref> New airport security procedures followed in the U.S., largely to protect against PETN.<ref name="latimes.com"/>
Pentaerythritol tetranitrate (PETN), also known as PENT, PENTA, TEN, corpent, penthrite (or—rarely and primarily in German—as nitropenta), is the nitrateester of pentaerythritol, and is structurally very similar to nitroglycerin. Penta refers to the five carbon atoms of the neopentane skeleton.
It is also used as a vasodilator drug to treat certain heart conditions, such as for management of angina.[1][2]
History
Penthrite was first synthesized in 1891 by Bernhard Tollens and P. Wigand by nitration of pentaerythritol.[3] The production of PETN started in 1912, when it was patented by the German government. PETN was used by the German Army in World War I.[4]
Properties
PETN is practically insoluble in water (0.01 g/100 ml at 50 °C), weakly soluble in common nonpolar solvents such as aliphatic hydrocarbons (like gasoline) or tetrachloromethane, but soluble in some other organic solvents, particularly in acetone (about 15 g/100 g of the solution at 20 °C, 55 g/100 g at 60 °C) and dimethylformamide (40 g/100 g of the solution at 40 °C, 70 g/100 g at 70 °C). PETN forms eutectic mixtures with some liquid or molten aromaticnitro compounds, e.g.trinitrotoluene (TNT) or tetryl. Due to its highly symmetrical structure, PETN is resistant to attack by many chemical reagents; it does not hydrolyze in water at room temperature or in weaker alkalineaqueous solutions. Water at 100 °C or above causes hydrolysis to dinitrate; presence of 0.1% nitric acid accelerates the reaction. Addition of TNT and other aromatic nitro derivatives lowers thermal stability of PETN.
In the environment, PETN undergoes biodegradation. Some bacteria denitrate PETN to trinitrate and then dinitrate, which is then further degraded. PETN has low volatility and low solubility in water, and therefore has low bioavailability for most organisms. Its toxicity is relatively low, and its transdermal absorption also seems to be low. It poses a threat for aquatic organisms. It can be degraded to pentaerythritol by iron metal.[5]
Production
Production is by the reaction of pentaerythritol with concentrated nitric acid to form a precipitate which can be recrystallized from acetone to give processable crystals.
C(CH2OH)4 + 4 HNO3 → C(CH2ONO2)4 + 4 H2O
Variations of a method first published in a US Patent 2,370,437 by Acken and Vyverberg (1945 to Du Pont) forms the basis of all current commercial production.
PETN is manufactured by numerous manufacturers as a powder about the consistency of fine popcorn salt, or together with nitrocellulose and plasticizer as thin plasticized sheets (e.g. Primasheet 1000 or Detasheet). PETN residues are easily detectable in hair of people handling it.[6] The highest residue retention is on black hair; some residues remain present even after washing.[7][8]
Medical Use
Like nitroglycerin (glyceryl trinitrate) and other nitrates, PETN is also used medically as a vasodilator in the treatment of heart conditions.[1][2] These drugs work by releasing the signaling gas nitric oxide in the body. The heart medicine Lentonitrat is nearly pure PETN.[9]
Monitoring of oral usage of the drug by patients has been performed by determination of plasma levels of several of its hydrolysis products, pentaerythritol dinitrate, pentaerythritol mononitrate and pentaerythritol, in plasma using gas chromatography-mass spectrometry.[10]
↑Russek H. I. (1966). "The therapeutic role of coronary vasodilators: glyceryl trinitrate, isosorbide dinitrate, and pentaerythritol tetranitrate". American Journal of Medical Science. 252 (1): 9–20. doi:10.1097/00000441-196607000-00002. PMID4957459.
↑R. Baselt, Disposition of Toxic Drugs and Chemicals in Man, 8th edition, Biomedical Publications, Foster City, CA, 2008, pp. 1201–1203.
Further reading
Cooper, Paul (1997). Explosives Engineering. Weinheim: Wiley-VCH. ISBN0-471-18636-8.