HMX

• Cyclotetramethylenetetranitramine
• HMX
• LX 14-0
• HW 4

Colorless crystals

Fixed

273-281 ° C ( decomposition)

Soluble in DMSO ( 455 g · kg -1 DMSO at 40 ° C)

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HMX is the common name for the explosive Cyclotetramethylenetetranitramine which belongs to the group of nitramines. In U.S. parlance it is called Homocyclonite or HMX ( high- molecular -weight RDX). The systematic name of HMX is 1,3,5,7- tetranitro -1 ,3,5,7 - tetrazoctan.

History

The substance was isolated in 1942 in Germany as a by- product of industrial synthesis of Hexogens (KA ) method, characterized chemically and by blasting examined, it showed no advantages over the RDX. About the same time it was separated in the U.S. analog as a by- product of the identical new Bachmann method, and evaluated. In the manufacture of the structurally similar octogen QDX formed.

Representation and extraction

The synthesis of HMX proceeds from Hexamethylentetramindinitrat, which is reacted in a first step by the action of acetic anhydride to give 1,5 -methylene- 3 ,7 -dinitro -1 ,3,5,7 - tetraazacyclooctan. Analogous to Bachmann method for preparing is carried out in the second step, the hexogen preparing the object compound by acetic acid, nitric acid and ammonium nitrate.

Properties

Physical Properties

It exists in four polymorphic forms, of which only the β - form has practical significance. This form has a necessary for a high detonation velocity particularly high density. It forms white crystals which decompose at 273-282 ° C. The compound is virtually insoluble in water. Solubilities in different solvents can be compared with those of hexogen.

For the detonation velocity values ​​are given at 9.110 m · s- 1 at a compressed density of 1.89 g · cm -3; it is thus slightly higher than that of RDX ( 8.750 m · s -1). In comparison, TNT detonates only with about 6,900 m · s -1. The heat of explosion is 5680 kJ / kg; it caused 920 l / kg combustion gases (Normal gas volume). The lead block expansion is 480 ml/10 g, the limiting diameter in steel sleeve test is 8 mm. The connection is impact and friction sensitive. The monkey test shows with an impact energy of 7.5 joules and the rubbing test with a pin load of 12 kp a positive result.

Chemical Properties

HMX is a heterocyclic eight-membered ring. His resistance to sulfuric acid and sodium hydroxide against is greater than that of Hexogens, presumably due to lower solubility so that it separation methods were developed. The solubility in acetone is much less than that of hexogen, whereby the separation of the hexogen HMX is possible by fractional crystallisation. For recrystallization dimethyl sulfoxide or nitromethane is suitable.

Toxicology of nitramines

RDX has no nitrite effects, it is slowly from the gastrointestinal tract and probably not absorbed by the skin. The minimum lethal dose for rats ( orally ) is 200 mg / kg. But be 50-100 mg / kg daily of rats, 50 mg / kg daily of dogs for several weeks tolerated with no blood changes, only some hyperexcitability was observed. Repeated exposure of RDX ( dust) or from impurities in the manufacturing process occurred in people seizures, eye and skin irritation.

About the toxicity of HMX is not known. However, it is likely similar central stimulant and convulsant effect as RDX.

Use

An exchange of RDX to HMX causes a gain in power for high power loads ( eg, shaped charges ). It can be used also called Octol mixtures with proportions of 25% or 30 % of trinitrotoluene.