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2 Central European Journal of Energetic Materials

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Relationship Between Electronic Charges at Nitrogen Atoms of Nitro Groups and Onsets of Thermal Decomposition of Polynitro Arenes

100%

Zeman S. , Friedl Z.

tom Vol. 1, nr 1

3-21

Thermal stability of twenty-five polynitro arenes has been examined by means of non-isothermal differential thermal analysis (DTA), and it was expressed as an onset of thermal decomposition, TD. Electronic charges, qN, at nitrogen atoms of the polynitro arene molecules were calculated by means of the ab initio DFT B3LYP/6-31G** method. The relationship was confirmed between the onsets TD and squares of the qN values for the nitro groups that are primarily split off. In the sense of this relationship, the compounds studied fall into five groups. The reason of this diversification and principle of the relationship existence are discussed. It is stated that stabilising influence of the crystal lattice of the studied polynitro arenes can be evaluated by DTA of solutions of these compounds in 1,3,5-trinitrobenzene (TNB).

A Relationship between 15N NMR Chemical Shifts and Detonation Characteristics of Polynitro Derivatives of Arenes and Polyazaarenes

88%

Zeman S. , Pešková M.

2005

tom Vol. 2, nr 3

71-84

The 15N NMR chemical shifts of eighteen polynitro arenes have been determined. The relationships were found and discussed between the characteristics of detonation and thermal decomposition, on the one hand, and 15N NMR chemical shifts of nitrogen atoms of the primarily split off nitro groups, on the other hand. Also the relationships are specified between the 15N NMR chemical shifts in the solid state of some polynitro derivatives of aminopyridines and aminopyrimidines, on the one hand, and squares of their detonation velocities, on the other. It has been stated that the chemical micromechanisms of primary fission processes of molecules of the studied compounds in the initiation by shock should be the same as in the case of their low-temperature thermal decomposition. Also mentioned is relevance of the modified Evans-Polanyi-Semenov relationship. On the basis of the findings presented it also has been stated that the detonation transformation itself of these polynitro compounds should be preceded by an induction period.