RDX and HMX Production

Both RDX and HMX are white, stable, crystalline solids. Both are much less toxic than TNT and may be handled with no physiological effect if appropriate precautions are taken to assure cleanliness of operations. Both RDX and HMX detonate to form mostly gaseous, low molecular weight products with little intermediate formation of solids. The calculated molar detonation products of RDX are 3.00 H2O, 3.00 N2,1.49 CO2, and 0.02 CO. RDX has been stored for as long as 10 months at 85°C without perceptible deterioration. 

At present, HMX is the highest-energy solid explosive produced on a large scale, primarily for military use. It exists in four polymorphic forms of which the beta form is the least sensitive and most stable and the type required for military use. The mole fraction products of detonation of HMX in a calorimetric bomb are 3.68 N2, 3.18 H2, 1.92 CO2, 1.06 CO, 0.97 C, 0.395 NH3, and 0.30 H2. 

Both RDX and HMX are substantially desensitized by mixing with TNT to form cyclotols (with RDX) and octols (with HMX) or by coating with waxes, synthetic polymers, and elastomeric binders. 

The two most common processes for making RDX and HMX use hexamethylenetetramine (hexamine) as starting material. The Bachmann process, now used exclusively in the United States, is a simplification of a series of complex reactions that may be summarized as follows  

In the Bachmann process, the reactants are mixed, and the slurry aged to complete the reaction and increase the 5ueld. The reaction vessels are stainless steel, jacketed, and temperature controlled. A solution of one part hexamine in 1.65 parts of acetic acid, and a solution of 1.50 parts of ammonium nitrate dissolved in 2.0 parts of nitric acid and 5.20 parts of acetic anhydride are added continuously to each of two reactors that are maintained at 65-72°C. The mixture is cycled in a loop in about 15 s from the reactor through a temperature-controlled jacketed reactor 

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Oxidizers. The characteristics of the oxidizer affect the baUistic and mechanical properties of a composite propellant as well as the processibihty. Oxidizers are selected to provide the best combination of available oxygen, high density, low heat of formation, and maximum gas volume in reaction with binders. Increases in oxidizer content increase the density, the adiabatic flame temperature, and the specific impulse of a propellant up to a maximum. The most commonly used inorganic oxidizer in both composite and nitroceUulose-based rocket propellant is ammonium perchlorate. The primary combustion products of an ammonium perchlorate propellant and a polymeric binder containing C, H, and O are CO2, H2, O2, and HCl. Ammonium nitrate has been used in slow burning propellants, and where a smokeless exhaust is requited. Nitramines such as RDX and HMX have also been used where maximum energy is essential. 

Numerous experimental studies have investigated the atomistic details of HE decomposition by examining the net products after thermal (low-pressure) decomposition (see, for example, Ref. 54). For RDX and HMX, the rate limiting reaction is most likely NO2 dissociation and a plethora of final products in the decomposition process have been isolated. Several theoretical studies have also... 

The decomposition reactions of RDX and HMX are stoichiometrically balanced-when it is assumed that CO, rather than COj, is formed as a combustion product ... 

NTO is being developed in many areas these include i) a substitute for ammonium perchlorate or ammonium nitrate in solid rocket propellants, since it does not liberate undesirable products such as HC1 and has quite a high burn rate compared to ammonium perchlorate and ammonium nitrate, ii) used as a burning rate modifier for composite propellants, iii) replacing RDX and HMX in composite solid propel-... 

The analysis of TNT in wastewaters is made simple and direct by LC using a UV detector at 220nm (Refs 81 158). An LC method suitable for the low level determination of Tetrvl in the presence of TNT, RDX and HMX is described (Ref 91). The adsorptive LC of TNT was demonstrated using poly(styrene-divinyl benzene) adsorbent and ethanol as the moving phase (Ref 112). HPLC was used for the separation of TNT from purification by-products of hexanitro-bibenzyl (Ref 69). Enzymatic action on TNT was supported by HPLC (Ref 155). HPLC chromatograms of TNT are included, together with data on TLC and color reactions of TNT in mixts (Ref 153). Pollutants in wastewater... 

Scope. The three major military expls (TNT, RDX and HMX), the four most important military proplnt materials (Nitrocellulose, Nitroglycerin, Nitroguanidine and Dinitrotoluene) and two volatile and expl by-products (Tetranitro-methane from TNT manufg and Methyl nitrate from RDX/HMX manufg) are discussed here. 

Methyl nitrate, a by-product of RDX and HMX manuf, boils at 65°C, and is quite volatile. It is extremely shock-sensitive. Methyl nitrate is apparently much weaker in its physiological effects than NG. Four-hour inhalation toxicity studies of its vapors gave LC50 values of... 

We examined the thermal decomposition of a number of nitramines in dilute solution and in the melt phase. The nitramines included acyclic dialkyl mononitramines, where the dialkyls were methyl, ethyl, propyl and isopropyl cyclic mononitramines (N-nitro-pipeiidine and N-nitropyrrolidine) and cycle multifunctional nitramines (N-dinitropiperazhe l,3-dinitro-l,3-diazacyclo-pentane l,3-dinitro-l,3-diazacycbhexane RDX and HMX). For all nitramines, the predominant condensed-phase product was the nitrosamine though the amount formed depending on the nitramine and the phase of the thermolysis. The common trigger in the decompositions was N-N02 ho mo lysis, but the fate of the resultant amine radical depended on the phase. In solution the radical was stabilized sufficiently so that it resisted further decomposition and, instead, reacted with NO to form nitrosamine. In vapor or condensed phase, the amine radical underwent further reaction therefore,... 

Nitration represents a major chemical reaction that plays an essential role in the production of most explosives. A variety of nitrocompounds ranging from C-nitrocompounds such as TNT to N-nitrocompounds such as RDX and HMX to 0-nitrocompounds such as trinitroglycerol are considered among the most energetic compounds. The preparation of these explosives is thus of substantial importance [8]. 

The decomposition products of RDX and HMX contain relatively high concentrations of N02 at the initial stage. Exothermic reaction between the N02 and other... 

The wide use of nitro organic based energetic chemicals (NOCs), such as the aromatic TNT, and the nonaromatic cyclic nitramines RDX and HMX has resulted in the contamination of terrestrial and aquatic systems. Several reports (see Chapters 3-5 and 7-9 of this book) described the toxic and carcinogenic effects of explosives and their degradation products to various terrestrial, aquatic, and avian receptors. However, to determine the true identity of the chemicals that cause toxicity, the transport and transformation mechanisms of these chemicals must be understood. 

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