Hexamine dinitrate, nitrolysis

Compound I is formed from Hexamine Dinitrate via nitrolysis... 

RDX. Gilpin Winkler (Ref 38b) measured a heat of nitration of — 88.0kcal/mole of hexa-mine for the reaction of hexamine with 97.5% nitric acid. They also obtained a value of — 140kcal/mole of hexamine for the formation of RDX from hexamine and Bachmann reagents (acetic anhydride, acetic acid, ammonium nitrate and nitric acid). Incidentally, Gilpin Winkler interpret their results to mean that hexamine dinitrate is an intermediate in the direct nitrolysis of hexamine to give RDX, while hexamine mononitrate is an intermediate in the Bachmann process of producing RDX... 

Nitrolysis of hexamine dinitrate with nitric acid - ammonium nitrate - acetic anhydride... 

An unusual feature of the KA-process is that the reaction is conducted at 60-80 °C. Solutions of nitric acid in acetic anhydride are known to be prone to dangerous fume off at temperatures above ambient. However, a saturated solution of ammonium nitrate in fuming nitric acid can be added to warmed acetic anhydride without such danger. In fact, these reactions are commonly conducted at 60-80 °C as a matter of safety by preventing a build-up of unreacted starting material. The hexamine used in these reactions is in the form of the dinitrate salt, which is formed as a crystalline salt on addition of a saturated aqueous solution of hexamine to concentrated nitric acid below 15 °C. The use of hexamine dinitrate in this process reduces the amount of nitric acid needed for the nitrolysis. 

The nitrolysis of hexamine at low temperature has led to the synthesis of a number of cyclic nitramines. The reaction of hexamine dinitrate (241) with 88 % nitric acid at -40 °C, followed by quenching the reaction mixture onto crushed ice, leads to the precipitation of 3,5-dinitro-3,5-diazapiperidinium nitrate (242) (PCX) in good yield PCX is an explosive equal in power to RDX but is slightly more sensitive to impact. The reaction of PCX (242) with sodium acetate in acetic anhydride yields l-acetyl-3,5-dinitro-l,3,5-triazacyclohexane (82) (TAX), which on further treatment with dilute alkali in ethanol yields the bicycle (243). ... 

The reaction of hexamine dinitrate (241) with 98% nitric acid at —30°C, followed by quenching with aqueous sodium nitrate, yields the nitrosamine (244). When the same reaction is cautiously quenched with ethanol the ethoxyether (245) is obtained. Treatment of the ethoxyether (245) with cold absolute nitric acid yields the bicyclic ether (246). ° Treatment of any of the cyclic nitramines (242)-(246) with nitric acid and ammonium nitrate in acetic anhydride yields RDX. ° Hexamine dinitrate is often used in low temperature nitrolysis experiments in order to avoid the initial exotherm observed on addition of hexamine to nitric acid. 

According to the investigations of Hirst, Carruthers et al. [41] and Vroom and Winkler [42], the action of nitric acid on hexamine dinitrate (IV) results in the formation of the substance (V) by nitrolysis. 

If the nitrolysis of hexamine dinitrate (IV) is conducted at a very low temperature, e.g. -40°C, then, as reported by Hirst et ah [41] it is not cyclonite which is formed, but a dinitrate of a dinitro derivative (la) (3,5-dinitro-3,5-diazapiperidinium nitrate) ... 

The transient formation of hexamine in method 4 was confirmed by Winkler, Gillies and Williams [60] (see equation (45)) who examined the reaction mechanism of cyclonite preparation by method 4. They found that hexamine dinitrate is formed at 35°C as an intermediate product. At the same time nitric acid is evolved hence nitrolysis of hexamine dinitrate may occur, in other words the mechanism of cyclo-nite formation would be similar to that of direct nitration of hexamine with nitric acid. 

Dimethylolnitramine (252) is inevitably present as its dinitrate ester (256) under the conditions of hexamine nitrolysis. This compound is extremely sensitive to hydrolysis but can be... 

Wright et al. [46] pointed out that apart from the compound (VII) nitrolysis of hexamine may also lead to the transient formation of l-di(hydroxymethyl)-amino-methyl-3,5-dinitro-l,3,5-triazacyclohexane (XIII) [(VI) is the dinitrate of (XIII)] through the nitrolysis of the bonds K and M ... 

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