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Electric Spark Sensitivity of Polynitro Arenes. Part II. Aspects of the Molecular Structure with Utilization of the Net Charges of Nitro Groups

Zeman S., Friedl Z., Kočí J.

Central European Journal of Energetic Materials

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2007

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Vol. 4, nr 4

23-31

EN

An ESZ KTTV instrument of a new, relatively simple construction has been applied to the determination of electric spark sensitivity (EES) of 31 polynitro arenes and their derivatives. Results obtained are compared with the theoretical DFT B3LYP/6-31G(d,p) Mulliken net charges of nitro groups, QNO2, which primarily react in the initiation by the spark. On the basis of analysis of the results obtained it is shown that intermolecular interaction plays in this initiation a considerable role. However, generally accepted presumption, that most positive QNO2 value represents a sensitivity of the given molecule, is not valid without reserve. If the polynitro aromatic molecule contains several potential reaction centres, the proper initiation might then be realized selectively (depending on the kind of initiation impulse).

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Electric Spark Sensitivity of Polynitro Arenes Part I. A Comparison of Two Instruments

Zeman S., Majzlík J., Kočí J.

Central European Journal of Energetic Materials

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2007

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Vol. 4, nr 3

15-24

EN

An ESZ KTTV instrument of a new, relatively simple construction has been applied to determination of electric spark sensitivity (EES) of 34 polynitro arenes and their derivatives. Results obtained are compared with those from measurements by means of older RDAD instrument. The analysis of relationship between the EES values obtained by measurements on the two instruments revealed that the relationship is not unequivocal. It is possible to come to the conclusion that the mechanisms of spark energy transfer into the reaction centre of molecule should be different in measurement on the two alternative instruments. Measurement by means of the ESZ KTTV system is more sensitive to molecular structure of the studied polynitro compounds.

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Electric Spark Sensitivity of Nitramines. Part II. A Problem of "Hot Spots"

Zeman S., Pelikán W., Majzlík J., Kočí J.

Central European Journal of Energetic Materials

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2006

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Vol. 3, nr 3

45-51

EN

Attention was focused on the influence of grain size upon the electric spark sensitivity of 1,3,5-trinitro-1,3,5-triazinane (hexogen) and 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (octogen). Also the dependence of this sensitivity is monitored upon the addition of hard and fine admixtures (crushed glass or diamond dust) to these compounds and sample of ?-HNIW. It was found that this artificial introduction of the said admixtures decreases the electric spark sensitivity of corresponding mixtures because the number of intergrain contact points of the nitramines grains in the volume unit is decreased by implementation of the foreign particles. It was also suggested that dislocations in the crystals should play some role here. It is stated that an impact component absents in relevant electric discharge.

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Electric Spark Sensitivity of Nitramines. Part I. Aspects of Molecular Structure

Zeman S., Pelikán W., Majzlík J., Friedl Z., Kočí J.

Central European Journal of Energetic Materials

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2006

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Vol. 3, nr 3

27-44

EN

An ESZ KTTV instrument of a new, relatively simple construction has been applied to determination of electric spark sensitivity (EES) of 16 nitramines. Results obtained are compared with those from measurements by means of an older RDAD instrument. Attention was focused both on the relationships between the EES values from both the instruments and theoretical B3LYP/6-311+G(d,p) N-NO2 bond dissociation energies, B3LYP/6-31G(d,p) Mulliken net charges of the nitro group, heats of fusion and 15N NMR chemical shifts of the nitrogen atoms of the most reactive nitro groups, respectively. It is stated a larger difference between results of both instruments. The EES values from both the instruments correlate with such characteristics of molecular structure which correspond to the primarily leaving nitro group in the nitramine molecule. It has been found that these relationships for ESZ KTTV results are strongly affected by molecular structure factors. It is also pointed out that the dislocations in the crystals should have some relation to electric spark sensitivity.