Hexamethylene triperoxide diamine (HMTD) is a

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 exp ...

organic compound Some chemical authorities define an organic compound as a chemical compound that contains a carbon–hydrogen or carbon–carbon bond; others consider an organic compound to be any chemical compound that contains carbon. For example, carbon-co ...

. HMTD is an

organic peroxide In organic chemistry, organic peroxides are organic compounds containing the peroxide functional group (). If the R′ is hydrogen, the compounds are called hydroperoxides, which are discussed in that article. The O−O bond of peroxides easily b ...

, a

heterocyclic compound A heterocyclic compound or ring structure is a cyclic compound that has atoms of at least two different elements as members of its ring(s). Heterocyclic organic chemistry is the branch of organic chemistry dealing with the synthesis, proper ...

with a cage-like structure. It is a

primary 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 has been considered as an initiating explosive for

blasting caps A detonator is a device used to make an explosive or explosive device explode. Detonators come in a variety of types, depending on how they are initiated (chemically, mechanically, or electrically) and details of their inner working, which of ...

in the early part of 20th century, mostly because of its high initiating power (higher than that of

mercury fulminate Mercury(II) fulminate, or Hg(CNO)2, is a primary explosive. It is highly sensitive to friction, heat and shock and is mainly used as a trigger for other explosives in percussion caps and detonators. Mercury(II) cyanate, though its chemical formula ...

) and its inexpensive production. As such, it was quickly taken up as a primary explosive in mining applications. However, it has since been superseded by more (chemically) stable compounds such as dextrinated

lead azide Lead(II) azide is an inorganic compound. More so than other azides, it is explosive. It is used in detonators to initiate secondary explosives. In a commercially usable form, it is a white to buff powder. Preparation and handling Lead(II) azi ...

and DDNP (which contains no lead or mercury). HMTD is widely used in amateur-made blasting caps.

Preparation and structure

First synthesised in 1885 by the German chemist Ludwig Legler, HMTD may be prepared by the reaction of an aqueous solution of

hydrogen peroxide Hydrogen peroxide is a chemical compound with the formula . In its pure form, it is a very pale blue liquid that is slightly more viscosity, viscous than Properties of water, water. It is used as an oxidizer, bleaching agent, and antiseptic, usua ...

and

hexamine Hexamethylenetetramine (HMTA), also known as 1,3,5,7-tetraazaadamantane, is a heterocyclic organic compound with diverse applications. It has the chemical formula (CH2)6N4 and is a white crystalline compound that is highly soluble in water and p ...

in the presence of an acid

catalyst Catalysis () is the increase in rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quick ...

, such as

citric acid Citric acid is an organic compound with the formula . It is a Transparency and translucency, colorless Weak acid, weak organic acid. It occurs naturally in Citrus, citrus fruits. In biochemistry, it is an intermediate in the citric acid cycle, ...

, acetic acid or dilute

sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid (English in the Commonwealth of Nations, Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen, ...

. The hydrogen peroxide needs to be at least 12% w/w concentration, as lower concentrations lead to poor yields. Citric acid is overall superior to other acids, providing a yield of up to about 50%. The molecule adopts a cage-like structure with the nitrogen atoms having an unusual

trigonal planar In chemistry, trigonal planar is a molecular geometry model with one atom at the center and three atoms at the corners of an equilateral triangle, called peripheral atoms, all in one plane. In an ideal trigonal planar species, all three ligands a ...

geometry.

Properties as an explosive

Like other organic peroxides, such as

acetone peroxide Acetone peroxide ( also called APEX and mother of Satan) is an organic peroxide and a primary explosive. It is produced by the reaction of acetone and hydrogen peroxide to yield a mixture of linear monomer and cyclic dimer, trimer, and tet ...

(TATP), HMTD is unstable and detonated by shock, friction, static electricity discharges, concentrated sulfuric acid, strong UV radiation and heat. Cases of detonation caused by the simple act of screwing a lid on a jar containing HMTD have been reported. Common static electricity discharges have been reported to cause detonation. It is, however, less unstable than many other peroxides under normal conditions; exposure to ultraviolet light increases its sensitivity. It also reacts with most common metals, which can lead to

detonation Detonation () is a type of combustion involving a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. Detonations propagate supersonically through shock waves with ...

. HMTD is chemically very stable when pure (free of acids, bases, and metal ions) and does not quickly sublime like its acetone counterparts. HMTD is a more powerful initiating explosive than mercury fulminate, but its poor thermal and chemical stability prevents its use in

detonator A detonator is a device used to make an explosive or explosive device explode. Detonators come in a variety of types, depending on how they are initiated (chemically, mechanically, or electrically) and details of their inner working, which of ...

s. Nevertheless, HMTD is one of the three most widely used primary explosives in improvised, amateur made blasting caps, the others being

TATP Acetone peroxide ( also called APEX and mother of Satan) is an organic peroxide and a primary explosive. It is produced by the reaction of acetone and hydrogen peroxide to yield a mixture of linear monomer and cyclic dimer, trimer, and tetram ...

and

silver acetylide Silver is a chemical element; it has Symbol (chemistry), symbol Ag () and atomic number 47. A soft, whitish-gray, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. ...

. HMTD is a common source of injury, particularly finger amputations, among amateur chemists. Most of these injuries are caused by small amounts of HMTD that inadvertently detonate in close proximity of fingers, since small amounts (grams) are generally not powerful enough to amputate fingers from distances larger than 5 – 10 cm. Calculated (Explo5) detonation pressure P_cj at crystal density 1.597 g/cm³ is 218 kbar with velocity of detonation VoD = 7777 m/s. Explosion temperature is 3141 K, energy of explosion is 5612 kJ/kg (or 3400 - 4000 kJ/kg per various sources) and volume of explosion gases at STP is calculated to be 826 L/kg. Loose powder has density close to 0.4 g/cm³, hence the common detonation velocities are closer to 3000 m/s and P_cj is closer to 15 kbar.

Sensitivity

HMTD is overall slightly more sensitive than fresh TATP and can be considered to be slightly more dangerous than an average primary explosive. The variance of friction force between different surfaces (e.g. different kinds of paper) is often greater than the variance between the friction sensitivity of a given pair of primary explosives. This leads to different values for friction sensitivity measured at different laboratories.

Terrorism

Despite no longer being used in any military application, and despite its shock sensitivity, HMTD remains a common home-made explosive and has been used in a large number of

suicide bombing A suicide attack (also known by a wide variety of other names, see below) is a deliberate attack in which the perpetrators knowingly sacrifice their own lives as part of the attack. These attacks are a form of murder–suicide that is ofte ...

s and other attacks throughout the world. For example, it was one of the components in the explosives intended to bomb Los Angeles International Airport in the

2000 millennium attack plots A series of Islamist terrorist attacks linked to al-Qaeda were planned to occur on or near January 1, 2000, in the context of millennium celebrations, including bombing plots against four tourist sites in Jordan, the Los Angeles International Ai ...

and the

2016 New York and New Jersey bombings On September 17–19, 2016, a series of three constructed bombs exploded and several unexploded devices were discovered in the New York metropolitan area alongside a shooting in Linden, New Jersey following a subsequent manhunt. The bombings an ...

, as well as one of the components of the explosives attempted to be made by the

neo-Nazi Neo-Nazism comprises the post–World War II militant, social, and political movements that seek to revive and reinstate Nazism, Nazi ideology. Neo-Nazis employ their ideology to promote hatred and Supremacism#Racial, racial supremacy (ofte ...

terrorist organization

Atomwaffen Division The Atomwaffen Division (''Atomwaffen'' meaning "atomic weapons" in GermanModern standard German prefers ''Kernwaffen'' () for the concept.), also known as the National Socialist Resistance Front, was an international far-right extremist and ...

in the United States.

References

{{DEFAULTSORT:Hexamethylene Triperoxide Diamine Organic peroxides Explosive chemicals Diamines Organic peroxide explosives