Military


PETN [Pentaerythritol tetranitrate]

Preliminary tests of the thwarted mail bomb attacks are reported to indicate both packages contained PETN, a powerful industrial explosive, the same chemical said to have been used in a failed attack on a Detroit-bound plane in late 2009. U.S. Homeland Security Secretary Janet Napolitano said the bombs sent from Yemen destined for the United States in her words "contained all the hallmarks of al-Qaida" and in particular its affiliate al-Qaida in the Arabian Peninsula.

On December 25, 2009, Umar Farouk Abdulmutallab, a Nigerian national, was accused of trying to ignite an incendiary device aboard a Northwest Airlines Flight headed to Detroit, MI; an act the White House declared "an attempted act of terrorism". The incendiary device was later identified by authorities of being a PETN-based device.

Pentaerythritol tetranitrate C5H8N4012 (PETN), an odorless white crystalline solid, has a specific gravity of solids of 1.76 and a confined detonation velocity of over 25,000 fps. PETN is an explosive chemical that is currently used as the primary ingredient in detonating fuses and as a component (mixed with hexahydro-1,2,5-trinitro-1,3,4-triazine) in "plastic" explosives such as Semtex.

PETN is a component of the plastic explosive (Semtex-H) used to destroy a commercial jet (Pan Am Flight 103) near Lockerbie, Scotland in 1988. PETN explosive was used by the so-called shoe bomber Richard Reid, who attempted to blow up an American Airlines flight between Paris, France, and Miami, Florida, in December 2001. The would-be assassin of Saudi Arabia's Prince Mohammed bin Nayef hid his bomb in his underwear, apparently believing that cultural taboos would prevent a search in that part of his body. Several news reports said the assailant hid the bomb inside his rectum, but the Saudi government discounted those reports. The prince was slightly injured when the bomb exploded in the August 2009 attack. The Saudis said they think the bomb weighed 100 grams.

PETN is used in Detonating Cord of which it is the explosive core (Primacord), where it develops a velocity rate of 21,000 feet per second. Detonating cord is insensitive to friction and ordinary shock, but may be exploded by rifle fire. It also detonates sympathetically with the detonation of an adjacent high explosive. Hot spots, formed by shock interaction with voids or defects in explosives, control the onset of detonation; although many mechanisms have been postulated and modeled, the actual mechanism(s) are unknown.

PETN is used as a priming composition in detonators, a base charge in blasting caps, and a core load for detonating fuse. PETN is one of the strongest known high explosives with a relative effectiveness factor (R.E. factor) of 1.66. It is more sensitive to shock or friction than TNT or tetryl, and it is never used alone as a booster. It is primarily used in booster and bursting charges of small caliber ammunition, in upper charges of detonators in some land mines and shells, and as the explosive core of primacord.

The term "detonating cord" has a usual meaning of flexible, coilable cord having a core of high explosive, the core being a secondary explosive, usually PETN. The term "low-energy detonating cord" or "LEDC", is conventionally used to mean detonating cord which will not reliably initiate itself when placed in contact with itself by coiling or crossing lengths of the cord, and which will not, when in an ungathered configuration, reliably directly initiate a less sensitive or secondary explosive receptor charge, e.g., those that comprise secondary explosive materials (e.g., Pentolite mixtures of PETN and trinitrotoluene ("TNT")) to the substantial exclusion of primary explosive materials.

One common booster material consists of 50 weight percent PETN (pentaerythritol tetranitrate) and 50 weight percent TNT (trinitrotoluene), available as Pentolite. During World War II the M9A1 2.36" Rocket Launcher (Bazooka) charge, with 8 oz of pentolite, could penetrate up to 5 inches of armor. In the manufacture of Pentolite, PETN was first refined by precipitation from an acetone solution with water, this PETN is then dissolved in acetone with TNT and the Pentolite is obtained by co-precipitation by addition of water. In 1943 samples of Pentolite prepared from both single and double refined PETN were submitted by the duPont Co. in order that it might be determined if they differed with respect to stability, sensitivity, and explosive power. The results of the Rifle Bullet Impact and Drop Tests suggest that Pentolite made from single refined PETN was slightly more sensitive than normal Pentolite, but not enough so to warrant the extra refining treatment of PETN.

Demolition charge, M118, commonly called Flex-X or sheet explosive, consists of 4 half-pound sheets of flexible explosive packed in a plastic envelope. Each sheet is approximately 3 inches wide, 12 inches long, and 1/4 inch thick. Note: The exact explosive contained in an M118 charge varies with the manufacturer. At present, some manufacturers use PETN as the basic explosive. Others use RDX. Charges manufactured in the future may include other explosives.

By 2006 candidate explosive replacements for the Comp C-4 blocks and the PETN detonating cord and relay cups were being evaluated. The PETN-loaded detonating cord is suspected of being the primary contributor to the detonation reactions observed in the baseline IM tests. The use of PETN detonating cords in a system of this type is no longer allowed in new systems due to DoD's restriction on the use of pure PETN beyond the fuze interrupter of a weapons system. Trade studies were performed to evaluate potential detonating cord replacements. Prior subscale IM tests conducted by the Navy on various detonating cords show that Comp A-5, CH-6, and PBXN-8 can pass bullet impact tests.

Pentaerythritol is a simple alcohol. Nitric acid is also a common reagent. But together they form a powerful explosive, PETN. Mix it with trinitramine, a naphthlyamine antioxidant, an alkyl phthalate plasticizer, and a styrene binder. You get SEMTEX.

The pure explosive materials RDX and PETN have extremely low vapor pressures, and the vapor pressures of plastic explosives are even lower, due to the presence of oils and plasticizing agents that give the plastic explosive its form and consistency. When these explosives are manufactured, they are often spiked with a high vapor pressure, nitrogen-containing compound called a taggant to make them more easily detectable. These taggants have high vapor pressures (similar to NG or EGDN), and their presence in the plastic explosives makes vapor detection possible. However, relying on the presence of the taggant for vapor detection of plastic explosives is risky, because old, homemade, and some foreign-made plastic explosives do not contain a taggant.

Structurally, PETN (Chemical Abstract Services Registry Number 78-11-5) resembles nitroglyerin, a compound whose pharmacological as well as explosive properties itshares. Thus, in the human health field, PETN and nitroglycerin are used medicinally in the treatment ofangina, through their shared vasodilatory action. However, for either drug, repeated exposure canestablish a sequence of tolerance, then dependence as the body adjusts to the presence of eitherhypotensive agent. Pentaerythritol tetranitrate (PETN, NF) is a drug used to prevent angina pectoris. PETN without a lactose stabilizer is used as an explosive.

PETN does not occur naturally, so the production and use of this kind of compound can lead to contamination of the environment. PETN is subject to biodegradation in untreated or unpreserved urine and feces. There also have been some reports of its degradation by bacteria, whose PETN reductase sequentially denitrates PETN into tri- and dinitrates. The last compound shown in the pathway, pentaerythritol dinitrate, is degraded further to unknown products.

In 1995 Haustein KO, Winkler U, Loffler A, Huller G. of the Abteilung Klinische Pharmakologie, Medizinische Hochschule Erfurt, Germany reported on a study of PETN's cardiovascular effects. The effects of 80 mg pentaerithrityl-tetranitrate (PETN) as suspension or formulated as tablets were compared to placebo in a single blind, randomized, crossover study in 18 healthy subjects (study A), and the bioequivalence of two tablet formulations (marketed Dilcoran 80 vs a new formulation) was studied in 24 healthy subjects after administration of single oral doses of 80 mg PETN according to a placebo controlled, randomized, double blind, two-way crossover study design (study B). The perfusion of the right middle finger was measured by rheography (altitude A of the changes of resistance and of the incisure D) before and 24 h post-dose, and blood pressure and heart rate were measured in supine position at the same time. The values of area under curve (AUC) of the ratio A/D were calculated by the trapezoidal rule. In study A the mean A/D-values were reduced from about 2.0 to about 1.3 after intake of PETN (solution or tablet) with a minimum 60 to 90 min postdose (solution) and 2 h postdose (tablet). A significant reduction in this ratio was seen up to 8 (solution) or 12 h (tablet) post dose. Changes in blood pressure were not observed while the heart rate decreased in the subjects of all three groups 1 to 2 h postdose followed by an increase by 6 to 10 beats per min. After subtraction of the AUC values of placebo from the PETN-derived AUC values, mean values of 6.61 (SD 1.52, solution) and 7.25 (SD 1.48, A/D*h, tablet) were calculated (p > 0.1, study A).



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