Main Page | See live article | Alphabetical index

Cyclotrimethylene trinitramine

Cyclotrimethylene trinitramine is an explosive material widely used by the military. Commonly called RDX (Royal Demolition eXplosive or incorrectly Research Department Explosive), but also cyclonite, or hexogen. Its formal name is sometimes rendered as Cyclotrimethylenetrinitramine.

In its pure synthesised state it is a white crystalline solid. As an explosive it is usually used in mixtures with other explosives and plasticizers or desensitizers. It is stable in storage and is considered the most powerful and brisant of the military high explosives.

RDX forms the base for a number of common military explosives: Composition A (wax-coated, granular explosive consisting of RDX and plasticizing wax), composition A5 (mixed with 1.5% stearic acid), composition B (castable mixtures of RDX and TNT), composition C (a plastic demolition explosive consisting of RDX, other explosives, and plasticizers), composition D, HBX (castable mixtures of RDX, TNT, powdered aluminum, and D-2 wax with calcium chloride), H-6 and Cyclotol.

Properties

It is a colourless solid, of density 1.82 g/cm. It is obtained by reacting concentrated nitric acid on hexamine. It is a heterocycle and has the shape of a ring. It starts to decompose at about 170C and melts at 204C. Its structural formula is: hexahydro-1,3,5-trinitro-1,3,5-triazine or (CH2-N-NO2)3

At room temperatures, it is a very stable product. It burns rather than explodes, and only detonates with a detonator, being unaffected even by small arms fire. It is less sensitive than pentaerytritol tetranitrate (PETN). However, it is very sensitive when crystalized, below -4C.

The manufacture of RDX can easily pollute soil and groundwater.

History

The discovery of RDX dates from the 1890s when a German (Hans Henning) offered it as a medicine. Its explosive properties were not recognized until 1920 (Herz?). In the 1920s RDX was produced by the direct nitration of hexamine. It was only in 1940 that an efficient production method was found, possibly at the McGill University Department of Chemistry (Meissner?). It was widely used during WW II, often in explosive mixtures with TNT such as Torpex (TNT (42%),RDX (40%) and aluminium (18%)). RDX was used in one of the first plastic explosives.

See also explosive.