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1

Novel High-Nitrogen Content Energetic Compounds with High Detonation and Combustion Performance for use in Plastic Bonded Explosives (PBXs) and Composite Solid Propellants

Keshavarz M. H., Abadi Y. H., Esmaeilpour K., Damiri S., Oftadeh M.

Central European Journal of Energetic Materials

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2018

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Vol. 15, no. 2

364--375

EN

Five novel high-nitrogen content (N>50%) derivatives of tetrazole are introduced in the study reported here. The assessment of various properties of these compounds were performed, which include physicothermal properties (crystal density, condensed phase heat of formation, melting point, enthalpy of fusion and entropy of fusion), detonation performance (velocity and pressure of detonation, detonation temperature and power), sensitivity with respect to external stimuli (impact, shock, friction and electric spark) and combustion performance (specific impulse). The predicted results of these compounds are compared with dihydroxylammonium 5,5’-bistetrazole-1,1’-diolate (TKX-50) and octanitro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) as a high performance ionic salt and a neutral explosive, respectively. The novel energetic compounds were found to have higher detonation and combustion performance than either TKX-50 or HMX. The new explosives are therefore good candidates to obtain high detonation and combustion performance in plastic bonded explosives (PBXs) and composite solid propellants, respectively.

2

Modelling of the Effect of Concentrated Nitration Conditions on the Efficiency of the Production of ,7-Dinitro-1,3,5,7-tetraazabicyclo[3,3,1]nonane (DPT)

Hadi Z., Esmaeilpour K., Damiri S., Afzali A., Keshavarz M. H.

Central European Journal of Energetic Materials

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2018

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Vol. 15, no. 1

72--84

EN

3,7-Dinitro-1,3,5,7-tetraazabicyclo[3,3,1]nonane (DPT) is one of the most important intermediates in the synthesis of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX). A suitably modified Bachmann process, nitrolysis of solid hexamine in the presence of ammonium nitrate-nitric acid and acetic anhydride on a laboratory scale, is introduced to increase the efficiency, production capacity and purity of the DPT produced. Various quantitative and qualitative analytical methods were used for the identification and quality control of the product. A central composite design (CCD) of experiments was used to optimize the production process, increasing the production capacity, reducing the amount of acetic acid as the reaction medium to a suitable limit, and examining the effects of the main factors impacting on the efficiency of the nitration, e.g. the volume of ammonium nitrate-nitric acid solution, nitration temperature reactor addition time and volume of acetic anhydride. The overall results indicated that DPT was obtained with an efficiency of 64.58% and a production capacity of 20.77 (100 g·mL−1).

3

Accurate Prediction of the Condensed Phase (Solid or Liquid) Heat of Formation of Triazolium-based Energetic Ionic Salts at 298.15 K

Jafari M., Davtalab M., Keshavarz M. H., Esmaeilpour K., Mosaviazar A., Ghasemi M. A., Amini M.

Central European Journal of Energetic Materials

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2018

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Vol. 15, no. 3

501--515

EN

A novel method is introduced for the reliable prediction of the condensed phase (solid or liquid) heat of formation (Δf H θ (c)) of triazolium-based energetic ionic salts (EISs) at 298.15 K. It is based on the influence of some specific elemental compositions of cations and anions as additive parts. Two correcting functions, as non-additive quantities, are also used to adjust the first part. The coefficients of the specific elemental compositions of cations and anions in the new correlation, with a negative sign as well as a negative correcting function in the triazolium-based EISs, can decrease the value of Δf H θ (c) for the corresponding EISs. The reported Δf H θ (c) values of 57 different triazolium-based EISs were used to derive the new model. For 34 triazolium-based EISs, where the outputs of quantum mechanical methods were available, the Root Mean Squared Error (RMSE) of the new model was 156.0 kJ/mol. Meanwhile, the RMSE of complicated quantum mechanical methods is very large, i.e. 298.0 kJ/mol. The high reliability of the new model was also confirmed for a further 5 complex triazolium-based EISs as compared to the results of quantum mechanical calculations.

4

A Novel Method for the Prediction of the Impact Sensitivity of Quaternary Ammonium-based Energetic Ionic Liquids

Keshavarz M. H., Esmaeilpour K., Khoshandam H., Keshavarz Z., Atabak H. H., Damiri S., Afzali A.

Central European Journal of Energetic Materials

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2017

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Vol. 14, no. 3

520--533

EN

Impact sensitivity is an important safety parameter for the assessment of the hazards of working with new energetic compounds including ionic molecular energetic materials. This paper introduces two novel simple correlations to assess the impact sensitivity of quaternary ammonium-based energetic ionic liquids, which are based on the elemental composition of cations and anions divided by the molecular weight of a desired ionic liquid as well as the contribution of specific cations and anions. For 72 ionic molecular systems as a training set, the root mean square (rms) deviations of predictions for these models relative to experiment are 11 J and 6 J, respectively. The reliability of the models has also been tested for a further three ionic compounds containing complex structures, which give rms deviations of 12 J and 6 J, respectively, with respect to the measured data. The results of the current study indicate that the accuracy of this novel method for the prediction of the impact sensitivity of quaternary ammonium-based energetic ionic liquids is not necessarily enhanced by greater complexity.

5

Increasing the Efficiency of the Production of 1,3,5,7-Tetranitro-1,3,5,7-tetrazocane (HMX)

Afzali A., Esmaeilpour K., Damiri S., Hadi Z., Keshavarz M. H.

Central European Journal of Energetic Materials

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2016

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Vol. 13, no. 4

845--858

EN

This work introduces a suitable method for the optimization of selective synthesis of 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX), as one of the most well-known high explosives, from the aspects of production capacity and efficiency, by nitration of 3,7-dinitro-1,3,5,7-tetraazabicyclo[3,3,1]nonane (DPT). The effective factors in the productive capacity of HMX and the synthesis of a product from raw DPT with high capacity, purity, and efficiency have been identified. The required qualitative and quantitative analyses were performed for the identification and confirmation of the product quality. In order to optimize the process of increasing the capacity of HMX production and evaluation of the effects of different factors on the production capacity, a series of experiments were designed and performed by using central composite design (CCD). Practical studies and statistical analyses showed good conformity between the model presented and the actual results, allowing the selective production of HMX with an efficiency of greater than 70% and a high production capacity.

6

A New Thermally-stable Insensitive High Explosive:N,N′-Bis(1,2,3,4-tetrazol-5-yl)-4,4′-diamino-2,2′,3,3′,5,5′,6,6′-octanitroazobenzene (BTeDAONAB)

Mousavi S., Esmaeilpour K., Keshavarz M. H.

Central European Journal of Energetic Materials

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2013

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Vol. 10, no. 4

455--465

EN

A novel high performance explosive compound, N,N′-bis(1,2,3,4-tetrazol5-yl)-4,4′-diamino-2,2′,3,3′,5,5′,6,6′-octanitroazobenzene( BTeDAONAB), is introduced which is a thermally stable, insensitive high explosive. The presence of −NH2, −N=N− groups and the tetrazole ring simultaneously in the BTeDAONAB unit surprisingly increases its thermal stability. For the identification and characterization of BTeDAONAB, different analytical techniques have been used, including melting point, IR, 1H NMR, 13C NMR spectroscopy, elemental analysis, differential thermal analysis (DTA), thermogravimetry (TG), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The sensitivity and detonation properties of BTeDAONAB were compared with 2,4,6-triamino1,3,5-trinitrobenzene (TATB) and N,N′-bis(1,2,4-triazol-3-yl-)-4,4′-diamino2,2′,3,3′,5,5′,6,6′-octanitroazobenzene (BTDAONAB), two well-known, thermally stable, insensitive high explosives, as well as hexanitrostilbene (HNS). These studies show that BTeDAONAB has favorable thermal stability with high performance.