DADN

DADNE, ein relative neuer, wenig empfindlicher Hochleistungsexplo-sivstoff, wurde von der Schwedischen FOI entwickelt. DADNE ist unloslich in Wasser, wenig loslich in Acetonitril und Cyclohexanon und loslich in DMSO, Dimethylformamid und N-Methylpyrrolidon. Es kann zu allergischen Hautreaktionen ftihren. 

The nitrolysis of cyclic polyamides offers a possible alternative industrial synthesis of HMX. The nitrolysis of l,3,5,7-tetraacetyl-l,3,5,7-tetraazacyclooctane (TAT) (79) and 1,5-diacetyl-3,7-dinitro-l,3,5,7-tetraazacyclooctane (DADN) (80) with a solution of dinitrogen pentoxide in anhydrous nitric acid gives HMX in 79 % and 98 % yields, respectively. Interestingly, the same reactions with nitric acid-acetic anhydride fail at room temperature. 

FOX-7 FOX-7 or l,l-diamino-2,2-dinitroethylene, (DADE/DADNE) [Structure (2.57)] is manufactured on a pilot-plant scale in Sweden by the nitration of 2-methyl-4,6-pyrimidinedione with mixed acids followed by aqueous hydrolysis. The outline of the method is as follows (Scheme 2.12) where the yield is around 80%. 

DADN Ph see 4,6-Dinitrobenzene-2-diazo-l-, oxide 2 B59 5 D1160-D1163... 

In the last several decades, the major advances in energetic materials have been the development of energetic polymers and a number of mono-molecular energetic compounds which do not fit neatly into the above categories [64]. These are in various stages of development, and it is difficult to predict which will become useful explosives or propellants. One unusual mixed functionality species is 1,1-diamino-2,2-dinitroethylene (FOX-7 or DADNE) (Fig. 11). It was synthesized in 1998, and several... 

II, for the simulation of molecular decomposition. The aim of the present work is to reveal step by step the mechanism of explosion and to find the way of reliable characterization of explosive materials using classical molecular dynamics simulations of the uni-molecular decomposition process. The structure of four molecules selected for dynamic simulations are reported in Ref. 12-15, for RDX, P-HMX, DADNE and NQ. Molecular structures are shown in the Fig. la-d. 

Analysis of dynamic trajectories revealed the mechanism of the molecular decomposition for selected molecules RDX, P-HMX, DADNE and NQ. The time dependence of the kinetic energy for these molecules is in the Fig. 3-7. The course of dynamic trajectories showed the similar character of the decomposition process for molecules of the I.group i.e. RDX, and P-HMX. Molecules of the Il.group - DADNE and NQ also exhibit similar features during decomposition process, however the character of the dynamic trajectories and... 

The course of dynamic trajectory for DADNE and NQ is very different from that for RDX and P-HMX, as one can see from the comparison of Fig. 3 -7. The difference is in the time dependence of kinetic energy after the start of decomposition process. In case of RDX and P-HMX the kinetic energy starts to increase dramatically during the decomposition, anyway the increase is monotonous. Decomposition of DADNE and NQ starts with the rupture of N-H bond followed by the rupture of C-N bond. However in this case the decomposition is accompanied with the large fluctuations of kinetic energy, as one can see in the Fig. 6 and 7. 

Classical molecular dynamics simulations revealed in details the mechanism of the molecular decomposition for four selected molecules RDX, P HMX, DADNE and NQ. Parameters obtained from dynamic trajectories agree with the experimental characteristics h, describing the impact sensitivity and with calculated values of detonation energy for all investigated molecules. The parameters obtained from dynamics simulations could be used for fast effective testing of explosive materials. Anyway the method of testing based on dynamic simulations still needs to be worked out more preciously. That means ... 

Thus Swedish scientists (at FOI) have very quickly synthesized, and established by their laboratory studies the favorable physical and chemical properties of DADNE, including its high performance and low sensitivity, resulting in a widely recognized useful new insensitive munition. Indeed, DADNE is now manufactured in quantity at NEXPLO-Bofors AB in Karlskoga. 

The decomposition mechanism for DADNE can be expected to be quite different from that for RDX and HMX. Even though DADNE has the same stoichiometry as RDX and HMX, structurally it bears little similarity to these molecules. Thus, possible reaction pathways involving unimolecular decomposition of these compounds would differ from those studied in DADNE. Instead of C-N02, N-N02 bond dissociation would occur, and the ring geometries would present the possibility of symmetric ring fission. 

In what follows we discuss first our studies of the simpler molecule nitroethylene, and subsequently proceed to calculations on the more complicated molecule DADNE. 

Having obtained a satisfactory description of nitroethylene decomposition, and a calibration of how modest basis DFT calculations fared in comparison to higher level calculations, we set out to apply them to the unimolecular decomposition of DADNE, which we consider next. 

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