Trinitrotoluene-hexogen mixture

The explosives most frequently used at present in the synthesis of detonation diamonds are mixtures of trinitrotoluene and hexogen. Trinitrotoluene is an explosive with a high negative oxygen balance. Explosive decomposition of trinitrotoluene releases a large amount of free carbon. Therefore, trinitrotoluene is the major source of carbon for the diamond phase in trinitrotoluene-hexogen mixtures. Hexogen (trimethylenetrinitramine) is a more potent explosive than trinitrotoluene and is used to maintain the detonation parameters of the mixture at a required level. 

Figure 2.21 Reduced chromatogram. Top separation of a mixture of explosives with peaks acetone, octogen, hexogen, tetryl, trinitrotoluene, and nitropenta. Bottom reduced chromatogram which shows only the signals of to, the critical peak pair of octogen and hexogen, and the last peak of nitropenta. Conditions column, 25cm X 4.6mm i.d. stationary phase, Grom-Sil 80 ODS-7 PH, 4 im mobile phase, 1 ml min gradient from 50-70% acetonitrile in water within 8 min UV detector 220 nm.

The most frequently employed starting explosives in indnstrial-scale production of diamond by detonation synthesis are, as a rnle, trinitrotoluene (TNT) and hexogen (also called RDX = Research Department Explosive), with detonation performed in a water medium to reach a higher productivity. The most complicated stage in the industrial process is chemical isolation of NC diamond from the detonation carbon prodnced in an explosion, which is actually a mixture of micro- and nanoparticles of graphite, varions forms of sp -hybridized carbon and impurities originally contained in the explosive itself, and construction materials of the synthesis vessel. For details of the technology used in detonation diamond synthesis, the reader can be referred to Ref. 19 and Section 9.23.2 for the structure of the detonation diamond particles, their properties, and applications. 

Besides the diamond phase, the condensed products of explosion recovered from the armored chamber after the explosion of a charge contain the nondiamond modifications of carbon and metal impurities. Depending on the method of synthesis, the diamond phase in the condensed carbon products of explosion is 30 to 75% of the weight of these products. Optimization of the detonation synthesis by the ratio of trinitrotoluene and hexogen in the mixture, by the ratio of the weight of exploded charge and the volume of the chamber and also the use of special coolants enables a stable 75% yield of the diamond phase in the condensed products of explosion. 

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