RDX
Encyclopedia
RDX, an initialism for Research Department Explosive, is an explosive nitroamine
widely used in military and industrial applications. It was developed as an explosive which was more powerful than TNT, and it saw wide use in WWII. RDX is also known as cyclonite, hexogen (particularly in German and German-influenced languages), and T4. Its chemical name is cyclotrimethylenetrinitramine; name variants include cyclotrimethylene-trinitramine and cyclotrimethylene trinitramine.
In its pure, synthesized state RDX is a white, crystalline solid. It is often used in mixtures with other explosives and plasticizer
s, phlegmatizer
s or desensitizers. RDX is stable in storage and is considered one of the most powerful and brisant
of the military high explosives.
, Woolwich, started investigating cyclonite as an explosive to use against German U-boat
s that were being built with thicker hulls. Britain wanted an explosive that was more powerful than TNT. For security reasons, Britain termed cyclonite as "Research Department Explosive" (R. D. X.). The term RDX appeared in the United States in 1946, but the name RDX is given without explanation. The first public reference in the United Kingdom to the name RDX, or R.D.X. to use the official title, appeared in 1948; its authors were the Managing Chemist, ROF Bridgwater
, the Chemical Research and Development Department, Woolwich
, and the Director of Royal Ordnance Factories, Explosives; again, it was referred to as simply RDX.
, often in explosive mixtures with TNT such as Torpex
, Composition B
, Cyclotols, and H6. RDX was used in one of the first plastic explosive
s. RDX is believed to have been used in many bomb plots including terrorist plots. The bouncing bomb
depth charges used in the "Dambusters Raid
" each contained 6600 pounds (2,993.7 kg) of Torpex.
RDX forms the base for a number of common military explosives:
Outside of military applications, RDX is also used in controlled demolition
to raze structures. The demolition of the Jamestown Bridge
in the US state of Rhode Island
is one example where RDX shaped charge
s were used to remove the span.
of RDX at a density of 1.76 g/cm³ is 8750 m/s.
It is a colourless solid, of crystal density 1.82 g/cm³. It is obtained by reacting concentrated nitric acid
with hexamine
.
It is a heterocycle and has the molecular shape of a ring. It starts to decompose at about 170 °C and melts at 204 °C. Its structural formula is: hexahydro-1,3,5-trinitro-1,3,5-triazine or (CH2-N-NO2)3.
At room temperature
, it is very stable. It burns rather than explodes and detonates only with a detonator
, being unaffected even by small arms
fire. (This is one of the properties that make it a useful military explosive.) It is less sensitive than pentaerythritol tetranitrate (PETN
). However, it is very sensitive when crystallized, below −4 °C.
Under normal conditions, RDX has a figure of insensitivity
of exactly 80 (RDX defines the reference point.).
RDX sublimes in vacuum
, which limits its use in pyrotechnic fastener
s for spacecraft
.
RDX when exploded in air has about 1.5 times the explosive power of TNT per unit weight and about 2.0 times per unit volume.
. The US produced about 15000 long ton per month during WW II and Germany about 7000 long ton per month. RDX had the major advantages of possessing greater explosive power than TNT used in the First World War, and requiring no additional raw materials for its manufacture.
patent
(patent No. 104280) for its manufacture, by nitrating
hexamine nitrate (hexamethylenetetramine nitrate) with concentrated nitric acid. In this 1898 patent, its properties as a medical compound were mentioned; however, three further German patents obtained by Henning in 1916 proposed its use in smokeless propellants. The German military started investigating its use in 1920 and referred to it as hexogen. Research and development findings were not published further until Edmund von Herz, described as an Austrian and later a German citizen, obtained a British patent in 1921 and a US patent in 1922. Both patent claims were initiated in Austria; and described the manufacture of RDX by nitrating hexamethylenetetramine. The British patent claims included the manufacture of RDX by nitration, its use with or without other explosives, and its use as a bursting charge and as a initiator. The US patent claim was for the use of a hollow explosive device containing RDX and a detonator cap containing RDX. In the 1930s, Germany developed improved production methods.
During the Second World War, Germany used the code names W Salt, SH Salt, K-method, the E-method and the KA-method. These represented the names of the developers of the various chemical processes used to prepare RDX. The W-method was developed by Wolfram in 1934 and gave RDX the code name "W-Salz". It used sulphamic acid, formaldehyde and nitric acid. SH-Salz (SH salt) was from Schnurr who developed a batch-process in 1937–38 based on nitrating hexamine. The K-method was from Knõffler and was based on adding ammonium nitrate to the hexamine / nitric acid process. The E-method was developed by Ebele, in Germany, and turned out to be identical to the Ross and Schiessler process described later. The KA-method was developed by Knöffler, in Germany, and turned out to be identical to the Bachmann process described later.
(UK), RDX was manufactured from 1933 by the Research Department in a pilot plant at the Royal Arsenal
in Woolwich
, London
; a larger pilot plant being built at the RGPF Waltham Abbey
just outside London in 1939. In 1939 a twin-unit industrial-scale plant was designed to be installed at a new 700 acres (283.3 ha) site, ROF Bridgwater
, away from London
; and production of RDX started at Bridgwater on one unit in August 1941. The ROF Bridgwater plant brought in ammonia and methanol as raw materials: the methanol was converted to formaldehyde and some of the ammonia converted to nitric acid, which was concentrated for RDX production. The rest of the ammonia was reacted with formaldehyde to produce hexamine. The hexamine plant was supplied by Imperial Chemical Industries
; and it incorporated some features based on data obtained from the United States (US). RDX was produced by continually adding hexamine and concentrated nitric acid to a cooled mixture of hexamine and nitric acid in the nitrator. The RDX was purified and processed for its intended use; and recovery and reuse of some methanol and nitric acid was also carried out. The hexamine-nitration and RDX purification plants were duplicated (i.e. twin-unit) to provide some insurance against loss of production due to fire, explosion or air attack.
The United Kingdom and British Empire
were fighting without allies against Nazi Germany
until the middle of 1941 and had to be self-sufficient. At that time (1941), the UK had the capacity to produce 70 long ton (160,000 lb) of RDX per week; both Canada
, an allied country and self-governing dominion within the British Empire, and the US were looked upon to supply ammunition and explosives, including RDX. By 1942 the Royal Air Force
's annual requirement was forecast to be 52000 long ton of RDX, much of which came from North America (Canada and the US).
Department of Chemistry. This was based on reacting paraformaldehyde and ammonium nitrate in acetic anhydride
. A UK patent application was made by Robert Walter Schiessler, Pennsylvania State College and James Hamilton Ross, at McGill, Canada, in May 1942 and the UK patent was issued in December 1947. Gilman states that the same method of production had been independently discovered by Ebele in Germany prior to Schiessler and Ross, but that this was not known by the Allies. Urbański provides details of five methods of production: this is listed as the (German) E-method.
and Hercules
had several decades of experience of manufacturing Trinitrotoluene (TNT) and had no wish to experiment with new explosives; a view also held by the US Army Ordnance, who proposed to continue using TNT. RDX had been tested by Picatinny Arsenal
in 1929 and it was regarded as too expensive and too sensitive. The Navy proposed to continue using ammonium picrate. In contrast, the view that new explosives were unnecessary was not shared by the National Defense Research Committee
(NDRC), who had visited The Royal Arsenal, Woolwich. James B. Conant, chairman of Division B, wished to involve academic research into this area. Conant therefore set up an Experimental Explosives Research Laboratory at the Bureau of Mines, Bruceton, Pennsylvania using direct Office of Scientific Research and Development
(OSRD) funding.
In 1941, the UK's Tizard Mission
visited the US Army and Navy departments and part of the information handed over included details of the "Woolwich" method of manufacture of RDX and its stabilisation by mixing it with beeswax
. The UK was asking that the US and Canada, combined, supply 220 short ton (440,000 lb) of RDX per day. A decision was taken by William H. P. Blandy
, Chief of the Bureau of Ordnance
to adopt RDX for use in mines and torpedoes. Given the immediate need for RDX, the US Army Ordnance, at Blandy's request, built a plant that just copied the equipment and process used at Woolwich. The result was the Wabash River Ordinance Works
run by E. I. du Pont de Nemours & Company. This works had the largest nitric acid plant in the world, at that time. The Woolwich process was expensive; it needed 11 pounds (5 kg) of strong nitric acid for every pound of RDX.
By early 1941, the NDRC was researching new processes. The Woolwich or direct nitration process has at least two serious disadvantages: (1) it used large amounts of nitric acid and (2) at least one-half of the formaldehyde is lost. One mole of hexamethylenetetramine could produce at most one mole of RDX. At least three laboratories with no previous explosive experience were tasked to develop better production methods for RDX; they were based at Cornell
, Michigan and Penn State
universities. Werner Emmanuel Bachmann
, from Michigan, successfully developed the "combination process" by combining the Canadian process with direct nitration. The combination process required large quantities of acetic anhydride instead of nitric acid in the old British "Woolwich process". Ideally, the combination process could produce two moles of RDX from each mole of hexamethylenetetramine.
Vast increases in production of RDX could not continue to rely on the use of the beeswax, first used in the Woolwich process, to desensitize the RDX. A substitute based on petroleum was developed at the Bruceton Explosives Research Laboratory.
, part of Eastman Kodak. The Eastman Chemical Company (TEC), Kingsport
, Tennessee
, a leading manufacturer of acetic anhydride, Werner Emmanuel Bachmann
successfully developed a continuous-flow manufacturing process for RDX. RDX was crucial to the war effort and the current batch-production process could not keep up. In February 1942, TEC built the Wexler Bend pilot plant and began producing small amounts of RDX. This led to the US government authorizing TEC to design and build Holston Ordnance Works (H.O.W.) in June 1942. By April 1943, RDX was being manufactured there. At the end of 1944, the Holston plant and the Wabash River Ordinance Works
(which used the Woolwich process) were making 25000 short ton (50 million pounds) of Composition B
per month.
The US Bachmann process for RDX was found to be richer in HMX
than the United Kingdom's RDX. This later led to a RDX plant using the Bachmann process being set up at ROF Bridgwater in 1955, to produce both RDX and HMX.
Karl Dönitz
was reputed to have claimed that "an aircraft can no more kill a U-boat than a crow can kill a mole
". However, by May 1942 Wellington bombers
began to deploy depth charge
s containing Torpex
, a mixture of RDX, TNT and aluminium, which had up to 50 percent more destructive power than TNT-filled depth charges. Considerable quantities of the RDX–TNT mixture were produced at the Holston Ordnance Works, with Tennessee Eastman developing an automated mixing and cooling process based around the use of stainless steel conveyor belt
s.
and the Jaipur bombings in 2008. It is also believed to be the explosive in the 1999 Russian apartment bombings, 2004 Russian aircraft bombings, and 2010 Moscow Metro bombings
.
Ahmed Ressam
, the al-Qaeda
Millennium Bomber, used a small quantity of RDX as one of the components in the explosives that he prepared to bomb Los Angeles International Airport on New Year's Eve
1999/2000; the combined explosives could have produced a blast forty times greater than that of a devastating car bomb
.
Nitroamine
Nitroamines are organic compounds that contain the nitroamino functional group, R2N-NO2. The R's are the continuation of the ring structure, see RDX. Examples of nitroamines are the explosives HMX, cyclotrimethylene trinitramine, Hexanitrohexaazaisowurtzitane and tetryl...
widely used in military and industrial applications. It was developed as an explosive which was more powerful than TNT, and it saw wide use in WWII. RDX is also known as cyclonite, hexogen (particularly in German and German-influenced languages), and T4. Its chemical name is cyclotrimethylenetrinitramine; name variants include cyclotrimethylene-trinitramine and cyclotrimethylene trinitramine.
In its pure, synthesized state RDX is a white, crystalline solid. It is often used in mixtures with other explosives and plasticizer
Plasticizer
Plasticizers or dispersants are additives that increase the plasticity or fluidity of the material to which they are added; these include plastics, cement, concrete, wallboard, and clay. Although the same compounds are often used for both plastics and concretes the desired effects and results are...
s, phlegmatizer
Phlegmatized
Phlegmatized is a term applied to an explosive that has had an agent added to stabilize or desensitize it. Sometimes this is desirable, to enable handling or to reduce the rate of combustion. Typical phlegmatizing agents include wax, paper, water, and paraffin. These agents are nearly always...
s or desensitizers. RDX is stable in storage and is considered one of the most powerful and brisant
Brisance
Brisance is the shattering capability of an explosive. It is a measure of the rapidity with which an explosive develops its maximum pressure. The term originates from the French verb "briser", which means to break or shatter...
of the military high explosives.
Name
RDX is also known, but less commonly, as cyclonite, hexogen (particularly in German and German-influenced languages), T4 and chemically as cyclotrimethylenetrinitramine. Tenney L Davis, writing in the US in 1943, stated it was generally known in the US as cyclonite; the Germans called it Hexogen, the Italians T4. In the 1930s, the Royal ArsenalRoyal Arsenal
The Royal Arsenal, Woolwich, originally known as the Woolwich Warren, carried out armaments manufacture, ammunition proofing and explosives research for the British armed forces. It was sited on the south bank of the River Thames in Woolwich in south-east London, England.-Early history:The Warren...
, Woolwich, started investigating cyclonite as an explosive to use against German U-boat
U-boat
U-boat is the anglicized version of the German word U-Boot , itself an abbreviation of Unterseeboot , and refers to military submarines operated by Germany, particularly in World War I and World War II...
s that were being built with thicker hulls. Britain wanted an explosive that was more powerful than TNT. For security reasons, Britain termed cyclonite as "Research Department Explosive" (R. D. X.). The term RDX appeared in the United States in 1946, but the name RDX is given without explanation. The first public reference in the United Kingdom to the name RDX, or R.D.X. to use the official title, appeared in 1948; its authors were the Managing Chemist, ROF Bridgwater
ROF Bridgwater
Royal Ordnance Factory Bridgwater was a factory which produced high explosives for munitions. It was located between the villages of Puriton and Woolavington in the Sedgemoor district of Somerset, UK; but was always known as ROF Bridgwater, after the nearest town...
, the Chemical Research and Development Department, Woolwich
Royal Arsenal
The Royal Arsenal, Woolwich, originally known as the Woolwich Warren, carried out armaments manufacture, ammunition proofing and explosives research for the British armed forces. It was sited on the south bank of the River Thames in Woolwich in south-east London, England.-Early history:The Warren...
, and the Director of Royal Ordnance Factories, Explosives; again, it was referred to as simply RDX.
Usage
RDX was widely used during World War IIWorld War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
, often in explosive mixtures with TNT such as Torpex
Torpex
Torpex is a secondary explosive 50% more powerful than TNT by mass. Torpex is composed of 42% RDX, 40% TNT and 18% powdered aluminium. It was used in the Second World War from late 1942. The name is short for Torpedo Explosive', having been originally developed for use in torpedoes...
, Composition B
Composition B
Composition B, colloquially "comp B", is an explosive consisting of castable mixtures of RDX and TNT. It is used as the main explosive filling in artillery projectiles, rockets, land mines, hand grenades, sticky bombs and various other munitions...
, Cyclotols, and H6. RDX was used in one of the first plastic explosive
Plastic explosive
Plastic explosive is a specialised form of explosive material. It is a soft and hand moldable solid material. Plastic explosives are properly known as putty explosives within the field of explosives engineering....
s. RDX is believed to have been used in many bomb plots including terrorist plots. The bouncing bomb
Bouncing bomb
A bouncing bomb is a bomb designed specifically to bounce to a target across water in a calculated manner, in order to avoid obstacles such as torpedo nets, and to allow both the bomb's speed on arrival at the target and the timing of its detonation to be pre-determined...
depth charges used in the "Dambusters Raid
Operation Chastise
Operation Chastise was an attack on German dams carried out on 16–17 May 1943 by Royal Air Force No. 617 Squadron, subsequently known as the "Dambusters", using a specially developed "bouncing bomb" invented and developed by Barnes Wallis...
" each contained 6600 pounds (2,993.7 kg) of Torpex.
RDX forms the base for a number of common military explosives:
- Composition A: Granular explosive consisting of RDX and plasticizing wax. Such as, composition A-5 (RDX coated with 1.5% stearic acidStearic acidStearic acid is the saturated fatty acid with an 18 carbon chain and has the IUPAC name octadecanoic acid. It is a waxy solid, and its chemical formula is CH316CO2H. Its name comes from the Greek word στέαρ "stéatos", which means tallow. The salts and esters of stearic acid are called stearates...
) and composition A-3 (91% RDX coated with 9% wax) - Composition BComposition BComposition B, colloquially "comp B", is an explosive consisting of castable mixtures of RDX and TNT. It is used as the main explosive filling in artillery projectiles, rockets, land mines, hand grenades, sticky bombs and various other munitions...
: Castable mixtures of 40% RDX and 60% TNT, with an extra 1% of wax added (desensitizer) - Composition CComposition CThe Composition C family is a family of related US-specified plastic explosives consisting primarily of RDX. All can be moulded by hand for use in demolition work and packed by hand into shaped charge devices. Variants have different proportions and plasticisers and include C-2, C-3, and C-4.The...
: The original composition C was used in World War II, but there have been subsequent variations including C-2, C-3, and C-4C-4 (explosive)C4 or Composition C4 is a common variety of the plastic explosive known as Composition C.-Composition and manufacture:C4 is made up of explosives, plastic binder, plasticizer and usually marker or odorizing taggant chemicals such as 2,3-dimethyl-2,3-dinitrobutane to help detect the explosive and...
. C-4 consists of RDX (91%), a plasticizer (which can be dioctyl adipate {DOA}, diethylhexyl, or dioctyl sebacate) (5.3%), a binder, which is usually polyisobutylene (2.1%), SAE 10 non-detergent motor oil (1.6%). - Composition CH-6: 97.5% RDX, 1.5% calcium stearate, 0.5% polyisobutylene, and 0.5% graphite.
- DBX (Depth Bomb Explosive): Castable mixture consisting of 21% RDX, 21% aluminium nitrate, 40% TNT, and 18% powdered aluminium. Developed during World War II, it was to be used in underwater munitions as a substitute for TorpexTorpexTorpex is a secondary explosive 50% more powerful than TNT by mass. Torpex is composed of 42% RDX, 40% TNT and 18% powdered aluminium. It was used in the Second World War from late 1942. The name is short for Torpedo Explosive', having been originally developed for use in torpedoes...
employing only half the amount of then-strategic RDX. As the supply of RDX became more adequate, the mixture was shelved. - CyclotolCyclotolCyclotol is an explosive consisting of castable mixtures of RDX and TNT.It is related to the more common Composition B, which is roughly 60% RDX and 40% TNT; various compositions of Cyclotol contain from 65% to 80% RDX....
: Castable mixture of RDX (50-80%) with TNT (20-50%) designated by the amount of RDX/TNT, such as Cyclotol 70/30. - HBXHBXHBX is a family of binary explosives that are composed of RDX, TNT, powdered aluminium, and D-2 wax with calcium chloride. It is used in missile warheads and underwater ordnance....
: Castable mixtures of RDX, TNT, powdered aluminium, and D-2 waxWaxthumb|right|[[Cetyl palmitate]], a typical wax ester.Wax refers to a class of chemical compounds that are plastic near ambient temperatures. Characteristically, they melt above 45 °C to give a low viscosity liquid. Waxes are insoluble in water but soluble in organic, nonpolar solvents...
with calcium chloride. - H-6: Castable mixture of RDX, TNT, powdered aluminum, and paraffin wax.
- PBXPolymer-bonded explosiveA polymer-bonded explosive, also called PBX or plastic-bonded explosive, is an explosive material in which explosive powder is bound together in a matrix using small quantities of a synthetic polymer...
: RDX is also used as a major component of many polymer-bonded explosivePolymer-bonded explosiveA polymer-bonded explosive, also called PBX or plastic-bonded explosive, is an explosive material in which explosive powder is bound together in a matrix using small quantities of a synthetic polymer...
s (PBX). RDX-based PBX's typically consist of RDX and a polymer/co-polymer binder. Examples of RDX-based PBX formulations include, but are not limited to: PBX-9007, PBX-9010, PBX-9205, PBX-9407, PBX-9604, PBXN-106, PBXN-3, PBXN-6, PBXN-10, PBXN-201, PBX-0280, PBX Type I, PBXC-116, PBXAF-108, etc. - SemtexSemtexSemtex is a general-purpose plastic explosive containing RDX and PETN. It is used in commercial blasting, demolition, and in certain military applications. Semtex became notoriously popular with terrorists because it was, until recently, extremely difficult to detect, as in the case of Pan Am...
: (Trade name): Plastic demolition explosives containing RDX and PETNPETNPentaerythritol tetranitrate , also known as PENT, PENTA, TEN, corpent, penthrite , is the nitrate ester of pentaerythritol. Penta refers to the five carbon atoms of the neopentane skeleton.PETN is most well known as an explosive...
as major energetic components. - TorpexTorpexTorpex is a secondary explosive 50% more powerful than TNT by mass. Torpex is composed of 42% RDX, 40% TNT and 18% powdered aluminium. It was used in the Second World War from late 1942. The name is short for Torpedo Explosive', having been originally developed for use in torpedoes...
: 42% RDX, 40% TNT, and 18% powdered aluminium. The mixture was designed during World War II and used mainly in underwater ordnance.
Outside of military applications, RDX is also used in controlled demolition
Controlled demolition
Controlled demolition refers to:* Demolition, the tearing-down of buildings and other structures* Controlled Demolition, Inc., Phoenix, Maryland firm that specializes in the use of explosives to create a controlled demolition of a structure...
to raze structures. The demolition of the Jamestown Bridge
Jamestown Bridge
The Jamestown Bridge, usually referred to as the Old Jamestown Bridge to avoid confusion with its replacement, the new Jamestown Verrazzano Bridge, was a cantilever truss bridge that connected Conanicut Island to mainland North Kingstown, Rhode Island, spanning the West passage of Narragansett Bay...
in the US state of Rhode Island
Rhode Island
The state of Rhode Island and Providence Plantations, more commonly referred to as Rhode Island , is a state in the New England region of the United States. It is the smallest U.S. state by area...
is one example where RDX shaped charge
Shaped charge
A shaped charge is an explosive charge shaped to focus the effect of the explosive's energy. Various types are used to cut and form metal, to initiate nuclear weapons, to penetrate armor, and in the oil and gas industry...
s were used to remove the span.
Properties
The velocity of detonationExplosive velocity
Explosive velocity, also known as detonation velocity or velocity of detonation , is the velocity at which the shock wave front travels through a detonated explosive. The data listed for a specific substance is usually a rough prediction based upon gas behavior theory , as in practice it is...
of RDX at a density of 1.76 g/cm³ is 8750 m/s.
It is a colourless solid, of crystal density 1.82 g/cm³. It is obtained by reacting concentrated nitric acid
Nitric acid
Nitric acid , also known as aqua fortis and spirit of nitre, is a highly corrosive and toxic strong acid.Colorless when pure, older samples tend to acquire a yellow cast due to the accumulation of oxides of nitrogen. If the solution contains more than 86% nitric acid, it is referred to as fuming...
with hexamine
Hexamine
Hexamethylenetetramine is a heterocyclic organic compound with the formula 6N4. This white crystalline compound is highly soluble in water and polar organic solvents. It has a cage-like structure similar to adamantane. It is useful in the synthesis of other chemical compounds, e.g. plastics,...
.
- (CH2)6N4 + 10HNO3 → (CH2-N-NO2)3 + 3CH2(ONO2)2 + NH4NO3 + 3H2O
It is a heterocycle and has the molecular shape of a ring. It starts to decompose at about 170 °C and melts at 204 °C. Its structural formula is: hexahydro-1,3,5-trinitro-1,3,5-triazine or (CH2-N-NO2)3.
At room temperature
Room temperature
-Comfort levels:The American Society of Heating, Refrigerating and Air-Conditioning Engineers has listings for suggested temperatures and air flow rates in different types of buildings and different environmental circumstances. For example, a single office in a building has an occupancy ratio per...
, it is very stable. It burns rather than explodes and detonates only with a detonator
Detonator
A detonator is a device used to trigger an explosive device. Detonators can be chemically, mechanically, or electrically initiated, the latter two being the most common....
, being unaffected even by small arms
Small arms
Small arms is a term of art used by armed forces to denote infantry weapons an individual soldier may carry. The description is usually limited to revolvers, pistols, submachine guns, carbines, assault rifles, battle rifles, multiple barrel firearms, sniper rifles, squad automatic weapons, light...
fire. (This is one of the properties that make it a useful military explosive.) It is less sensitive than pentaerythritol tetranitrate (PETN
PETN
Pentaerythritol tetranitrate , also known as PENT, PENTA, TEN, corpent, penthrite , is the nitrate ester of pentaerythritol. Penta refers to the five carbon atoms of the neopentane skeleton.PETN is most well known as an explosive...
). However, it is very sensitive when crystallized, below −4 °C.
Under normal conditions, RDX has a figure of insensitivity
Figure of Insensitivity
Figure of Insensitivity is an inverse scale of measure of the impact sensitivity of an explosive substance. In this particular context the term 'Insensitivity' refers to the likelihood of initiation/detonation by accidental means e.g. impact, friction, electrostatic discharge, application of...
of exactly 80 (RDX defines the reference point.).
RDX sublimes in vacuum
Vacuum
In everyday usage, vacuum is a volume of space that is essentially empty of matter, such that its gaseous pressure is much less than atmospheric pressure. The word comes from the Latin term for "empty". A perfect vacuum would be one with no particles in it at all, which is impossible to achieve in...
, which limits its use in pyrotechnic fastener
Pyrotechnic fastener
A pyrotechnic fastener is a fastener, usually a nut or bolt, that incorporates a pyrotechnic charge that can be initiated remotely. One or more explosive charges embedded within the bolt are typically activated by an electric current, and the charge breaks the bolt into two or more pieces...
s for spacecraft
Spacecraft
A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....
.
RDX when exploded in air has about 1.5 times the explosive power of TNT per unit weight and about 2.0 times per unit volume.
History
RDX was used by both sides in World War IIWorld War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
. The US produced about 15000 long ton per month during WW II and Germany about 7000 long ton per month. RDX had the major advantages of possessing greater explosive power than TNT used in the First World War, and requiring no additional raw materials for its manufacture.
Germany
The discovery of RDX dates from 1898 when Georg Friedrich Henning obtained a GermanGermany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
patent
Patent
A patent is a form of intellectual property. It consists of a set of exclusive rights granted by a sovereign state to an inventor or their assignee for a limited period of time in exchange for the public disclosure of an invention....
(patent No. 104280) for its manufacture, by nitrating
Nitration
Nitration is a general chemical process for the introduction of a nitro group into a chemical compound. The dominant application of nitration is for the production of nitrobenzene, the precursor to methylene diphenyl diisocyanate...
hexamine nitrate (hexamethylenetetramine nitrate) with concentrated nitric acid. In this 1898 patent, its properties as a medical compound were mentioned; however, three further German patents obtained by Henning in 1916 proposed its use in smokeless propellants. The German military started investigating its use in 1920 and referred to it as hexogen. Research and development findings were not published further until Edmund von Herz, described as an Austrian and later a German citizen, obtained a British patent in 1921 and a US patent in 1922. Both patent claims were initiated in Austria; and described the manufacture of RDX by nitrating hexamethylenetetramine. The British patent claims included the manufacture of RDX by nitration, its use with or without other explosives, and its use as a bursting charge and as a initiator. The US patent claim was for the use of a hollow explosive device containing RDX and a detonator cap containing RDX. In the 1930s, Germany developed improved production methods.
During the Second World War, Germany used the code names W Salt, SH Salt, K-method, the E-method and the KA-method. These represented the names of the developers of the various chemical processes used to prepare RDX. The W-method was developed by Wolfram in 1934 and gave RDX the code name "W-Salz". It used sulphamic acid, formaldehyde and nitric acid. SH-Salz (SH salt) was from Schnurr who developed a batch-process in 1937–38 based on nitrating hexamine. The K-method was from Knõffler and was based on adding ammonium nitrate to the hexamine / nitric acid process. The E-method was developed by Ebele, in Germany, and turned out to be identical to the Ross and Schiessler process described later. The KA-method was developed by Knöffler, in Germany, and turned out to be identical to the Bachmann process described later.
UK
In the United KingdomUnited Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
(UK), RDX was manufactured from 1933 by the Research Department in a pilot plant at the Royal Arsenal
Royal Arsenal
The Royal Arsenal, Woolwich, originally known as the Woolwich Warren, carried out armaments manufacture, ammunition proofing and explosives research for the British armed forces. It was sited on the south bank of the River Thames in Woolwich in south-east London, England.-Early history:The Warren...
in Woolwich
Woolwich
Woolwich is a district in south London, England, located in the London Borough of Greenwich. The area is identified in the London Plan as one of 35 major centres in Greater London.Woolwich formed part of Kent until 1889 when the County of London was created...
, London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...
; a larger pilot plant being built at the RGPF Waltham Abbey
Waltham Abbey Royal Gunpowder Mills
The Royal Gunpowder Mills, Waltham Abbey, an Anchor Point of the European Route of Industrial Heritage, , set in of parkland and containing 21 buildings of major historical importance, mixes history, science, and attractive surroundings...
just outside London in 1939. In 1939 a twin-unit industrial-scale plant was designed to be installed at a new 700 acres (283.3 ha) site, ROF Bridgwater
ROF Bridgwater
Royal Ordnance Factory Bridgwater was a factory which produced high explosives for munitions. It was located between the villages of Puriton and Woolavington in the Sedgemoor district of Somerset, UK; but was always known as ROF Bridgwater, after the nearest town...
, away from London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...
; and production of RDX started at Bridgwater on one unit in August 1941. The ROF Bridgwater plant brought in ammonia and methanol as raw materials: the methanol was converted to formaldehyde and some of the ammonia converted to nitric acid, which was concentrated for RDX production. The rest of the ammonia was reacted with formaldehyde to produce hexamine. The hexamine plant was supplied by Imperial Chemical Industries
Imperial Chemical Industries
Imperial Chemical Industries was a British chemical company, taken over by AkzoNobel, a Dutch conglomerate, one of the largest chemical producers in the world. In its heyday, ICI was the largest manufacturing company in the British Empire, and commonly regarded as a "bellwether of the British...
; and it incorporated some features based on data obtained from the United States (US). RDX was produced by continually adding hexamine and concentrated nitric acid to a cooled mixture of hexamine and nitric acid in the nitrator. The RDX was purified and processed for its intended use; and recovery and reuse of some methanol and nitric acid was also carried out. The hexamine-nitration and RDX purification plants were duplicated (i.e. twin-unit) to provide some insurance against loss of production due to fire, explosion or air attack.
The United Kingdom and British Empire
British Empire
The British Empire comprised the dominions, colonies, protectorates, mandates and other territories ruled or administered by the United Kingdom. It originated with the overseas colonies and trading posts established by England in the late 16th and early 17th centuries. At its height, it was the...
were fighting without allies against Nazi Germany
Nazi Germany
Nazi Germany , also known as the Third Reich , but officially called German Reich from 1933 to 1943 and Greater German Reich from 26 June 1943 onward, is the name commonly used to refer to the state of Germany from 1933 to 1945, when it was a totalitarian dictatorship ruled by...
until the middle of 1941 and had to be self-sufficient. At that time (1941), the UK had the capacity to produce 70 long ton (160,000 lb) of RDX per week; both Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, an allied country and self-governing dominion within the British Empire, and the US were looked upon to supply ammunition and explosives, including RDX. By 1942 the Royal Air Force
Royal Air Force
The Royal Air Force is the aerial warfare service branch of the British Armed Forces. Formed on 1 April 1918, it is the oldest independent air force in the world...
's annual requirement was forecast to be 52000 long ton of RDX, much of which came from North America (Canada and the US).
Canada
A different method of production to the Woolwich process, was found and used in Canada, possibly at the McGill UniversityMcGill University
Mohammed Fathy is a public research university located in Montreal, Quebec, Canada. The university bears the name of James McGill, a prominent Montreal merchant from Glasgow, Scotland, whose bequest formed the beginning of the university...
Department of Chemistry. This was based on reacting paraformaldehyde and ammonium nitrate in acetic anhydride
Acetic anhydride
Acetic anhydride, or ethanoic anhydride, is the chemical compound with the formula 2O. Commonly abbreviated Ac2O, it is the simplest isolatable acid anhydride and is a widely used reagent in organic synthesis...
. A UK patent application was made by Robert Walter Schiessler, Pennsylvania State College and James Hamilton Ross, at McGill, Canada, in May 1942 and the UK patent was issued in December 1947. Gilman states that the same method of production had been independently discovered by Ebele in Germany prior to Schiessler and Ross, but that this was not known by the Allies. Urbański provides details of five methods of production: this is listed as the (German) E-method.
UK, US and Canadian production and development
At the beginning of the 1940s, the major US explosive manufacturers, E. I. du Pont de Nemours & CompanyDuPont
E. I. du Pont de Nemours and Company , commonly referred to as DuPont, is an American chemical company that was founded in July 1802 as a gunpowder mill by Eleuthère Irénée du Pont. DuPont was the world's third largest chemical company based on market capitalization and ninth based on revenue in 2009...
and Hercules
Hercules Inc.
Hercules, Inc., was a chemical and munitions manufacturing company based in Wilmington, Delaware, which was formed in 1912 as the Hercules Powder Company. Hercules was spun-off from the DuPont Corporation as a result of U.S. federal government actions in the field of antitrusts...
had several decades of experience of manufacturing Trinitrotoluene (TNT) and had no wish to experiment with new explosives; a view also held by the US Army Ordnance, who proposed to continue using TNT. RDX had been tested by Picatinny Arsenal
Picatinny Arsenal
The Picatinny Arsenal is an American military research and manufacturing facility located on a lot in northern New Jersey near Lake Denmark. The Arsenal is the headquarters of the United States Army Armament Research, Development and Engineering Center...
in 1929 and it was regarded as too expensive and too sensitive. The Navy proposed to continue using ammonium picrate. In contrast, the view that new explosives were unnecessary was not shared by the National Defense Research Committee
National Defense Research Committee
The National Defense Research Committee was an organization created "to coordinate, supervise, and conduct scientific research on the problems underlying the development, production, and use of mechanisms and devices of warfare" in the United States from June 27, 1940 until June 28, 1941...
(NDRC), who had visited The Royal Arsenal, Woolwich. James B. Conant, chairman of Division B, wished to involve academic research into this area. Conant therefore set up an Experimental Explosives Research Laboratory at the Bureau of Mines, Bruceton, Pennsylvania using direct Office of Scientific Research and Development
Office of Scientific Research and Development
The Office of Scientific Research and Development was an agency of the United States federal government created to coordinate scientific research for military purposes during World War II. Arrangements were made for its creation during May 1941, and it was created formally by on June 28, 1941...
(OSRD) funding.
In 1941, the UK's Tizard Mission
Tizard Mission
The Tizard Mission officially the British Technical and Scientific Mission was a British delegation that visited the United States during the Second World War in order to obtain the industrial resources to exploit the military potential of the research and development work completed by the UK up...
visited the US Army and Navy departments and part of the information handed over included details of the "Woolwich" method of manufacture of RDX and its stabilisation by mixing it with beeswax
Beeswax
Beeswax is a natural wax produced in the bee hive of honey bees of the genus Apis. It is mainly esters of fatty acids and various long chain alcohols...
. The UK was asking that the US and Canada, combined, supply 220 short ton (440,000 lb) of RDX per day. A decision was taken by William H. P. Blandy
William H. P. Blandy
William Henry Purnell Blandy , known to friends as "Spike", was an admiral in the United States Navy during World War II.-Biography:...
, Chief of the Bureau of Ordnance
Bureau of Ordnance
The Bureau of Ordnance was the U.S. Navy's organization responsible for the procurement, storage, and deployment of all naval ordnance, between the years 1862 and 1959.-History:...
to adopt RDX for use in mines and torpedoes. Given the immediate need for RDX, the US Army Ordnance, at Blandy's request, built a plant that just copied the equipment and process used at Woolwich. The result was the Wabash River Ordinance Works
Newport Chemical Depot
The Newport Chemical Depot, previously known as the Wabash River Ordinance Works and the Newport Army Ammunition Plant, was a bulk chemical storage and destruction facility in west central Indiana, thirty miles north of Terre Haute operated by the United States Army...
run by E. I. du Pont de Nemours & Company. This works had the largest nitric acid plant in the world, at that time. The Woolwich process was expensive; it needed 11 pounds (5 kg) of strong nitric acid for every pound of RDX.
By early 1941, the NDRC was researching new processes. The Woolwich or direct nitration process has at least two serious disadvantages: (1) it used large amounts of nitric acid and (2) at least one-half of the formaldehyde is lost. One mole of hexamethylenetetramine could produce at most one mole of RDX. At least three laboratories with no previous explosive experience were tasked to develop better production methods for RDX; they were based at Cornell
Cornell University
Cornell University is an Ivy League university located in Ithaca, New York, United States. It is a private land-grant university, receiving annual funding from the State of New York for certain educational missions...
, Michigan and Penn State
Pennsylvania State University
The Pennsylvania State University, commonly referred to as Penn State or PSU, is a public research university with campuses and facilities throughout the state of Pennsylvania, United States. Founded in 1855, the university has a threefold mission of teaching, research, and public service...
universities. Werner Emmanuel Bachmann
Werner Emmanuel Bachmann
Werner Emmanuel Bachmann was a U.S. chemist. Bachmann was born in Detroit, Michigan where he studied chemistry and chemical engineering at Wayne State University and later at the University of Michigan in Ann Arbor nearby...
, from Michigan, successfully developed the "combination process" by combining the Canadian process with direct nitration. The combination process required large quantities of acetic anhydride instead of nitric acid in the old British "Woolwich process". Ideally, the combination process could produce two moles of RDX from each mole of hexamethylenetetramine.
Vast increases in production of RDX could not continue to rely on the use of the beeswax, first used in the Woolwich process, to desensitize the RDX. A substitute based on petroleum was developed at the Bruceton Explosives Research Laboratory.
Bachmann process
The NDRC tasked three companies to develop pilot plants. They were the Western Cartridge Company, E. I. du Pont de Nemours & Company and Tennessee Eastman CompanyEastman Chemical Company
Eastman Chemical Company is a United States based chemical company, engaged in the manufacture and sale of chemicals, fibers, and plastics. Eastman has 11 manufacturing sites in seven countries, supplying its products throughout the world...
, part of Eastman Kodak. The Eastman Chemical Company (TEC), Kingsport
Kingsport, Tennessee
Kingsport is a city located mainly in Sullivan County with some western portions in Hawkins County in the US state of Tennessee. The majority of the city lies in Sullivan County...
, Tennessee
Tennessee
Tennessee is a U.S. state located in the Southeastern United States. It has a population of 6,346,105, making it the nation's 17th-largest state by population, and covers , making it the 36th-largest by total land area...
, a leading manufacturer of acetic anhydride, Werner Emmanuel Bachmann
Werner Emmanuel Bachmann
Werner Emmanuel Bachmann was a U.S. chemist. Bachmann was born in Detroit, Michigan where he studied chemistry and chemical engineering at Wayne State University and later at the University of Michigan in Ann Arbor nearby...
successfully developed a continuous-flow manufacturing process for RDX. RDX was crucial to the war effort and the current batch-production process could not keep up. In February 1942, TEC built the Wexler Bend pilot plant and began producing small amounts of RDX. This led to the US government authorizing TEC to design and build Holston Ordnance Works (H.O.W.) in June 1942. By April 1943, RDX was being manufactured there. At the end of 1944, the Holston plant and the Wabash River Ordinance Works
Newport Chemical Depot
The Newport Chemical Depot, previously known as the Wabash River Ordinance Works and the Newport Army Ammunition Plant, was a bulk chemical storage and destruction facility in west central Indiana, thirty miles north of Terre Haute operated by the United States Army...
(which used the Woolwich process) were making 25000 short ton (50 million pounds) of Composition B
Composition B
Composition B, colloquially "comp B", is an explosive consisting of castable mixtures of RDX and TNT. It is used as the main explosive filling in artillery projectiles, rockets, land mines, hand grenades, sticky bombs and various other munitions...
per month.
The US Bachmann process for RDX was found to be richer in HMX
HMX
HMX, also called octogen, is a powerful and relatively insensitive nitroamine high explosive, chemically related to RDX. Like RDX, the name has been variously listed as High Melting eXplosive, Her Majesty's eXplosive, High-velocity Military eXplosive, or High-Molecular-weight rdX.The molecular...
than the United Kingdom's RDX. This later led to a RDX plant using the Bachmann process being set up at ROF Bridgwater in 1955, to produce both RDX and HMX.
Military compositions
The United Kingdom's intention in World War II was to use "desensitised" RDX: in the original Woolwich process RDX coated with beeswax, but changed to a RDX coated with petroleum-based product, based on the work carried out at Bruceton. In the event the UK was unable to obtain sufficient RDX to meet its needs. Some of this shortfall was met by substituting a mixture of ammonium nitrate and TNT.Karl Dönitz
Karl Dönitz
Karl Dönitz was a German naval commander during World War II. He started his career in the German Navy during World War I. In 1918, while he was in command of , the submarine was sunk by British forces and Dönitz was taken prisoner...
was reputed to have claimed that "an aircraft can no more kill a U-boat than a crow can kill a mole
Mole (animal)
Moles are small cylindrical mammals adapted to a subterranean lifestyle. They have velvety fur; tiny or invisible ears and eyes; and short, powerful limbs with large paws oriented for digging. The term is especially and most properly used for the true moles, those of the Talpidae family in the...
". However, by May 1942 Wellington bombers
Vickers Wellington
The Vickers Wellington was a British twin-engine, long range medium bomber designed in the mid-1930s at Brooklands in Weybridge, Surrey, by Vickers-Armstrongs' Chief Designer, R. K. Pierson. It was widely used as a night bomber in the early years of the Second World War, before being displaced as a...
began to deploy depth charge
Depth charge
A depth charge is an anti-submarine warfare weapon intended to destroy or cripple a target submarine by the shock of exploding near it. Most use explosives and a fuze set to go off at a preselected depth in the ocean. Depth charges can be dropped by either surface ships, patrol aircraft, or from...
s containing Torpex
Torpex
Torpex is a secondary explosive 50% more powerful than TNT by mass. Torpex is composed of 42% RDX, 40% TNT and 18% powdered aluminium. It was used in the Second World War from late 1942. The name is short for Torpedo Explosive', having been originally developed for use in torpedoes...
, a mixture of RDX, TNT and aluminium, which had up to 50 percent more destructive power than TNT-filled depth charges. Considerable quantities of the RDX–TNT mixture were produced at the Holston Ordnance Works, with Tennessee Eastman developing an automated mixing and cooling process based around the use of stainless steel conveyor belt
Conveyor belt
A conveyor belt consists of two or more pulleys, with a continuous loop of material - the conveyor belt - that rotates about them. One or both of the pulleys are powered, moving the belt and the material on the belt forward. The powered pulley is called the drive pulley while the unpowered pulley...
s.
Terrorism
The 1993 Bombay bombings were the first terrorist blasts in Mumbai which used RDX by placement into several vehicles as bombs. RDX was main component used for the 2006 Mumbai train bombings11 July 2006 Mumbai train bombings
The 11 July 2006 Mumbai train bombings were a series of seven bomb blasts that took place over a period of 11 minutes on the Suburban Railway in Mumbai, the capital of the Indian state of Maharashtra and the nation's financial capital. The bombs were set off in pressure cookers on trains...
and the Jaipur bombings in 2008. It is also believed to be the explosive in the 1999 Russian apartment bombings, 2004 Russian aircraft bombings, and 2010 Moscow Metro bombings
2010 Moscow Metro bombings
The 2010 Moscow Metro bombings were suicide bombings carried out by two womenduring the morning rush hour of March 29, 2010, at two stations of the Moscow Metro , with roughly 40 minutes interval between...
.
Ahmed Ressam
Ahmed Ressam
Ahmed Ressam is an Algerian al-Qaeda member who lived in Montreal, Canada.He was convicted of attempting to bomb the Los Angeles International Airport on New Year's Eve 1999, as part of the foiled 2000 millennium attack plots...
, the al-Qaeda
Al-Qaeda
Al-Qaeda is a global broad-based militant Islamist terrorist organization founded by Osama bin Laden sometime between August 1988 and late 1989. It operates as a network comprising both a multinational, stateless army and a radical Sunni Muslim movement calling for global Jihad...
Millennium Bomber, used a small quantity of RDX as one of the components in the explosives that he prepared to bomb Los Angeles International Airport on New Year's Eve
New Year's Eve
New Year's Eve is observed annually on December 31, the final day of any given year in the Gregorian calendar. In modern societies, New Year's Eve is often celebrated at social gatherings, during which participants dance, eat, consume alcoholic beverages, and watch or light fireworks to mark the...
1999/2000; the combined explosives could have produced a blast forty times greater than that of a devastating car bomb
Car bomb
A car bomb, or truck bomb also known as a Vehicle Borne Improvised Explosive Device , is an improvised explosive device placed in a car or other vehicle and then detonated. It is commonly used as a weapon of assassination, terrorism, or guerrilla warfare, to kill the occupants of the vehicle,...
.
External links
- ADI Limited (Australia). Archive.org leads to Thales group products page that shows some military specifications.
- NLM Hazardous Substances Databank (US) – Cyclonite (RDX)