Octogen

The formation of octogen in method 5 will be discussed below. 

Octogen, known in Britain as HMX, i.e. cyclotetramethylenetetramine, 1,3,5,7-tetranitro-l,3,5,7-tetrazacyclo-octane, is a white crystalline substance which occurs under several polymorphous forms differing from one another in specific gravity and sensitiveness to impact. Usually octogen is obtained in / form, which is the least sensitive to impact (Table 21). 

McCrone [69] found that octogen is polymorphic and exists in four forms I (/ ), II (a), III O ) and IV ( 5). The first three are stable at room temperature, but HMX-IV transforms very readily. 

All the crystalline forms were examined by Wright etal. [70]. They examined X-ray diffraction pattern, infra-red spectra and dielectric constants. They concluded that the HMX polymorphs are actually lattice-caged conformational modifications. 

Stability of crystalline form metastable stable metastable labile 

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Octadiene-3,5-diyne-l, 8-dimethoxy-9-octadecynoic acid Octogen (dry)... 

Octogen. Ger name for Cyclotetramethylenetetra nitramine (HMX). See Vol 3, C605-R to C610-R Refs 1) B.T. Fedoroff et al, Dictionary of Explosives, Ammunition and Weapons, German Section . PATR 2510 (1958), 89-R 2) Urbanski 3... 

Octenoic acid, physical properties, 5 31t Octocrylene, cosmetic uv absorber, 7 846t Octogen, 10 735-736... 

Cyclotetramethylentetranitramine, wetted or HMX, wetted or Octogen, wetted with not less than 15 percent water, by mass 0226... 

Ortahydro-1,3,5,7-tetranitro-l,3,5,7-tetrazodne (fl-HMX, Octogen, Cyclotetramethylene tetranitramine) Very powerful explosive used as a main high explosive... 

High melting explosive or Her Majesty s explosive (HMX) is chemically known as cyclotetramethylene tetranitramine or l,3,5,7-tetranitro-l,3,5,7-tetraazacyclooctane [Structure (2.15)]. It is also known as octogen. It was first discovered by Bachmann in 1941 by modifying the Bachmann or Combination Process which was originally discovered for RDX. The main product is HMX and subsequent purification... 

HMX is a white crystalline substance and exists in four polymorphic modifications, the P form being most stable and least sensitive. The a and forms exist at room temperature but all forms transform to 8 polymorph above 160 °C. Octogen is usually obtained in the p form which is less sensitive to impact and has a density of 1.91 gem-3 and m.p. of 291 °C. HMX and RDX are almost alike in chemical reactivity. It is non-hygroscopic, insoluble in water and soluble in organic solvents similar to RDX. They differ only in that ... 

Explosives such as RDX (hexogen) and HMX (octogen) are important military explosives and generally a binder is used along with these explosives for two reasons ... 

It also provides a method of obtaining a chemically pure preparation, free from octogen. The reaction proceeds stepwise. It will be discussed more fully on p. 123 (Brockmann, Downing and Wright [12]). 

Nitrolysis of the compound (V) may also lead to the formation of the substance (XI) containing an eight-membered ring, called octogen (HMX) (see p. 117) which always accompanies cyclonite, but slightly reduces its power. 

It appears that apart from cyclonite, octogen (XI), a N-acetyl derivative (XXX) and a number of nitramines, mainly chain compounds, less stable than cyclonite, are also formed by this method, in side-reactions. Hence the cyclonite obtained has a relatively low melting point (190-195°C) and may be less stable than that prepared by other methods. The conduct of the reaction in the presence of boron fluoride reduces the number of by-products formed. 

In method 5, as in method 1, nitrolysis of hexamethylenetetramine occurs, the alcohol groups so produced being esterified with acetic anhydride and not with nitric anhydride as in method 1. The most important by-product formed to the extent of nearly 10% by method 5 is octogen (XI). It is produced as outlined above, as a result of hexamine nitrolysis (p. 90). 

On synthesis of cyclonite from paraformaldehyde, ammonium nitrate and acetic acid (method 4), products with cyclic structure, chiefly cyclonite and octogen, may arise due to the polymerization of the transiently-formed, hypothetical methylene-nitramine (XXVIII) [67] ... 

A mixture of cyclonite and octogen, rich in octogen, is best prepared by method 5, i.e. from hexamine nitrate, ammonium nitrate and acetic anhydride. A particularly large amount of octogen is formed when the product is prepared by Bachmann s method at temperatures ranging from 73 to 78°C and the mixture is then cooled to 25°C and filtered. This mixture m.p. 191-202°, contains approximately 10% of octogen. 

The ratio of cyclonite to octogen produced by method 5 was examined by Epstein and Winkler [72]. They found that in general reduction in the amount of ammonium nitrate used for the reaction reduces the yield of cyclonite and increases that of octogen. 

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