PLX, abbreviation of Picatinny Liquid Explosive, is a liquid binary
explosive
An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An exp ...
. It is a mixture of 95%
nitromethane
Nitromethane, sometimes shortened to simply "nitro", is an organic compound with the chemical formula . It is the simplest organic nitro compound. It is a polar liquid commonly used as a solvent in a variety of industrial applications such as i ...
(NM) along with 5%
ethylene diamine
Ethylenediamine (abbreviated as en when a ligand) is the organic compound with the formula C2H4(NH2)2. This colorless liquid with an ammonia-like odor is a basic amine. It is a widely used building block in chemical synthesis, with approximately ...
(EDA) as a sensitizer. Other
amine
In chemistry, amines (, ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (), wherein one or more hydrogen atoms have been replaced by a substituent su ...
compounds can be used instead of ethylene diamine, such as
triethylene tetramine
Triethylenetetramine (TETA and trien), also known as trientine (INN) when used medically, is an organic compound with the formula H2NHCH2CH2NH2sub>2. The pure freebase is a colorless oily liquid, but, like many amines, older samples assume a yell ...
,
diethylenetriamine
Diethylenetriamine (abbreviated and also known as 2,2’-Iminodi(ethylamine)) is an organic compound with the formula HN(CH2CH2NH2)2. This colourless hygroscopic liquid is soluble in water and polar organic solvents, but not simple hydrocarbons. ...
or
ethanolamine
Ethanolamine (2-aminoethanol, monoethanolamine, ETA, or MEA) is an organic chemical compound with the formula or . The molecule is bifunctional, containing both a primary amine and a primary alcohol. Ethanolamine is a colorless, viscous liquid wi ...
, but EDA has been found to be the most effective amine additive. PLX is a fairly powerful
high explosive
An explosive (or explosive material) is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure. An e ...
, marginally exceeding the destructive yield of
TNT
Trinitrotoluene (), more commonly known as TNT, more specifically 2,4,6-trinitrotoluene, and by its preferred IUPAC name 2-methyl-1,3,5-trinitrobenzene, is a chemical compound with the formula C6H2(NO2)3CH3. TNT is occasionally used as a reage ...
.
Properties
PLX, when mixed, is a transparent liquid with a yellowish tint. Ethylene diamine is very volatile, requiring the contents to be sealed if any storage is intended. Generally, for safety purposes, the contents are transported separately and mixed on site. PLX is known to have a
velocity of detonation
Explosive velocity, also known as detonation velocity or velocity of detonation (VoD), is the velocity at which the shock wave front travels through a detonated explosive. Explosive velocities are always faster than the local speed of sound in the ...
(VoD) of anywhere between 6,000 and 7,000 m/s, depending on diameter. Although greatly sensitized by the addition of EDA, PLX still requires a powerful
blasting cap
A detonator, frequently a blasting cap, is a device used to trigger an explosive device. Detonators can be chemically, mechanically, or electrically initiated, the last two being the most common.
The commercial use of explosives uses electr ...
or a small booster charge to successfully detonate.
Uses and discovery
PLX was invented during
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...
by the
Picatinny Arsenal
The Picatinny Arsenal ( or ) is an American military research and manufacturing facility located on of land in Jefferson and Rockaway Township in Morris County, New Jersey, United States, encompassing Picatinny Lake and Lake Denmark. The Ar ...
in New Jersey. It was originally designed to clear
minefield
A land mine is an explosive device concealed under or on the ground and designed to destroy or disable enemy targets, ranging from combatants to vehicles and tanks, as they pass over or near it. Such a device is typically detonated automati ...
s by being spread via plane over the targeted area or poured from a safe distance and detonated by troops on the ground.
This explosive can also be
gel
A gel is a semi-solid that can have properties ranging from soft and weak to hard and tough. Gels are defined as a substantially dilute cross-linked system, which exhibits no flow when in the steady-state, although the liquid phase may still di ...
led through the addition of
nitrocellulose
Nitrocellulose (also known as cellulose nitrate, flash paper, flash cotton, guncotton, pyroxylin and flash string, depending on form) is a highly flammable compound formed by nitrating cellulose through exposure to a mixture of nitric acid and ...
,
ETN, or any number of soluble
nitrate esters
In organic chemistry, a nitrate ester is an organic functional group with the formula , where R stands for any organic residue. They are the esters of nitric acid and alcohols. A well-known example is nitroglycerin, which is not a ''nitro'' com ...
or
gelling agent
A gel is a semi-solid that can have properties ranging from soft and weak to hard and tough. Gels are defined as a substantially dilute cross-linked system, which exhibits no flow when in the steady-state, although the liquid phase may still dif ...
s. This allows for powdered metals, such as
aluminum
Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It h ...
or
magnesium
Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ...
, to be suspended in the mixture. The metal powders act as
fuel
A fuel is any material that can be made to react with other substances so that it releases energy as thermal energy or to be used for work. The concept was originally applied solely to those materials capable of releasing chemical energy bu ...
, increasing heat and energy output but lowering the
brisance
In explosives engineering, brisance (; , ) is the shattering capability of a high explosive, determined mainly by its detonation pressure.
Practical uses
Brisance is of practical importance for determining the effectiveness of an explosion in ...
and
velocity of detonation
Explosive velocity, also known as detonation velocity or velocity of detonation (VoD), is the velocity at which the shock wave front travels through a detonated explosive. Explosive velocities are always faster than the local speed of sound in the ...
. The result is a more sustained blast wave and a "push and heave" effect, desirable for
thermobaric
A thermobaric weapon, also called an aerosol bomb, a vacuum bomb or a fuel air explosive (FAE), is a type of explosive that uses oxygen from the surrounding air to generate a high-temperature explosion. The fuel–air explosive is one of the b ...
purposes. Trzciński reports that 200 grams of a mixture of NM with PMMA as gelling agent and AlMg (45:55, mean particle size = 63 microns) as fuel, in a ratio of 67.2/2.8/30 by mass, has a peak overpressure of 120 kPa 2 m from the(open air) blast site, a 1.65 TNT equivalency in peak pressure, and a 1.62 equivalency in shockwave impulse. As a reference, 104 kPa is widely regarded as a pressure where 50% of eardrums fail. This is still 3 - 5 times less than the pressure needed to achieve a 50% fatality rate via pulmonary injury as per the Bass/Bowen equations (standing adult, facing any direction).
PLX has been implicated as one of the materials capable of being used in catastrophic terrorism, as most steel core columns can not withstand the detonation of 10 – 30 kg PLX in direct contact (explosive on bare steel). Nitromethane and its gelling agents are freely sold to the public in the US, though. Its sale to the public was banned in the EU in September 2014.
It was the supposed explosive used in the film ''
Die Hard with a Vengeance
''Die Hard with a Vengeance'' is a 1995 American action thriller film directed by John McTiernan (who directed the first installment). It was written by Jonathan Hensleigh, based on the screenplay ''Simon Says'' by Hensleigh and on the characte ...
''.{{Citation needed, date=October 2007 However, the film grossly exaggerated the sensitivity of this explosive mixture.
PLX was one of the explosives used to down
Korean Air Flight 858
Korean Air Flight 858 was a scheduled international passenger flight between Baghdad, Iraq, and Seoul, South Korea. On 29 November 1987, the aircraft flying that route exploded in mid-air upon the detonation of a bomb planted inside an overhead ...
along with
C-4.
References
Binary explosives
Liquid explosives