Hale nitrolysis reaction

The stoichiometry of the Hale nitrolysis reaction is very dependent on reaction conditions. Even so, this reaction has been postulated to conform to the stoichiometry in Equation (5.21) °° and Equation (5.22). ° Based on the assumption that one mole of hexamine produces one mole of RDX the Hale nitrolysis reaction commonly yields 75-80 % of RDX. 

Dimethylolnitramine (252) is known to be present under the conditions of the Hale nitrolysis. If the Hale nitrolysis reaction is quenched, the RDX removed by filtration and the aqueous liquors neutralized to remove DPT, the remaining filtrate can be extracted into ether and that solution evaporated over water to give an aqueous solution of dimethylolnitramine (252). ... 

In this method, first established by Herz and later studied by Hale, hexamine is introduced into fuming nitric acid which has been freed from nitrous acid. The reaction is conducted at 20-30 °C and on completion the reaction mixture is drowned in cold water and the RDX precipitates. The process is, however, very inefficient with some of the methylene and nitrogen groups of the hexamine not used in the formation of RDX. The process of nitrolysis is complex with formaldehyde and some other fragments formed during the reaction undergoing oxidation in the presence of nitric acid. These side-reactions mean that up to eight times the theoretical amount of nitric acid is needed for optimum yields to be attained. 

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