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1

Effect of Adding 5-Aminotetrazole to a Modified U.S. ArmyTerephthalic Acid White Smoke Composition

Glück J., Klapötke T. M., Shaw A. P.

Central European Journal of Energetic Materials

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2017

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Vol. 14, no. 3

489--500

EN

Military visible obscuration compositions (obscurants, smokes) play an important role on today’s battlefield. For many years, the known toxicity or ageing problems of established formulations were commonly accepted since there was a lack of alternatives. Since the U.S. Army stopped producing the AN-M8 hexachloroethane (HC) smoke grenade, the M83 terephthalic acid (TA) smoke grenade has been used in its place. This cool-burning, less toxic, but also low efficiency white smoke formulation cannot compete with HC-based formulations in terms of obscuration performance. In this context, we have explored the use of 5-aminotetrazole (5-AT) as an additive and fuel in the known TA system. Remarkably, it has been found that sugar is not necessarily required in the formulations, which has implications for the future improvement of sublimation-condensation smoke compositions, including coloured smoke compositions. In small-scale tests, it was found that replacing sucrose with 5-AT in the formulations resulted in significantly improved smoke persistence.

2

Explosive Properties of 4,4’,5,5’-Tetranitro-2,2’-bi-1H-imidazole Dihydrate

Lewczuk R., Szala M., Rećko J., Cudziło S., Klapötke T. M., Trzciński W. A., Szymańczyk L.

Central European Journal of Energetic Materials

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2016

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Vol. 13, no. 3

612--626

EN

This paper reports measured explosive properties of 4,4’,5,5’-tetranitro-2,2’-bi-1H-imidazole dihydrate (TNBI•2H2O). Non-isothermal kinetics analysis, calorimetric measurements, detonability tests, small-scale shock reactivity tests (SSRT), detonation velocity measurements and cylinder tests were performed. The results of the cylinder tests were used to determine the acceleration ability of TNBI•2H2O. Some experiments were conducted also with TNT, NTO, FOX-7 and RDX. Our experimental studies have shown that TNBI•2H2O is a thermodynamically stable compound, surpassing TNT with regard to its energetic and detonation parameters. The results of the SSRT indicate that this material has better performance in small charges than RDX, FOX-7 and NTO.

3

Experimental Study on the Heat Resistant Explosive 5,5’-Bis(2,4,6-trinitrophenyl)-2,2’-bi(1,3,4-oxadiazole) (TKX-55): the Jet Penetration Capability and Underwater Explosion Performance

Klapötke T. M., Witkowski T. G., Wilk Z., Hadzik J.

Central European Journal of Energetic Materials

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2016

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Vol. 13, no. 4

821--837

EN

Ongoing research to find new explosives which are stable at high temperatures focuses on compounds which comply with the strict requirements which must be fulfilled in order for a compound to be of use in deep oil-well and gas drilling applications. Great efforts have been focused on the development of new, thermally stable explosives which are stable at even higher temperatures than hexanitrostilbene, and which also show superior performance. In the group of recently synthesized thermally stable explosives, 5,5’-bis(2,4,6-trinitrophenyl)-2,2’-bi(1,3,4-oxadiazole) (TKX-55) is one of the most promising prospective candidates for use in practical applications, due to its physicochemical properties as well as its convenient synthesis. Therefore, further investigation into the performance of TKX-55 in shaped charge applications was undertaken. This study was focused on the investigation of the jet penetration capability of conical shaped charges filled with TKX-55, in comparison with recently used other explosives. The kinetic energy of the jet depends on the brisance of the explosive which is used. In order to experimentally investigate the shattering effect of TKX-55, the Underwater Explosion Test was applied. Based on the collected data, the total energy, as the sum of the primary shock wave energy (the brisance) and the bubble gas energy (the heaving effect), was calculated.

4

A New Energetic Binder: Glycidyl Nitramine Polymer

Betzler F. M., Hartdegen V. A., Klapötke T. M., Sproll S. M.

Central European Journal of Energetic Materials

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2016

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Vol. 13, no. 2

289--300

EN

A new energetic glycidyl-based polymer containing nitramine groups (glycidyl nitramine polymer, GNAP) was synthesized using glycidyl azide polymer (GAP) as the starting material. The synthesis involved Staudinger azide-amine conversion, followed by carbamate protection of the amino group, nitration with nitric acid (100%) and trifluoroacetic anhydride and was concluded by deprotection with aqueous ammonia. The products obtained were characterized by elemental analysis and vibrational spectroscopy (IR). The energetic properties of GNAP were determined using bomb calorimetric measurements and calculated with the EXPLO5 V6.02 computer code, showing better values regarding the energy of explosion (ΔEU = −4813 kJ kg−1), the detonation velocity (VDet = 7165 m•s−1), as well as the detonation pressure (pCJ = 176 kbar), than the comparable polymers GAP and polyGLYN. The explosion properties were tested by impact sensitivity (IS), friction sensitivity (FS), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and electrostatic discharge (ESD) equipment. The results revealed GNAP to be insensitive towards friction and electrostatic discharge, less sensitive towards impact (40 J) and a decomposition temperature (170 °C) in the range of polyGLYN.

5

Preparation and Characterization of 1-(5-Azido-1H-1,2,4-triazol-3-yl)tetrazole

Izsák D., Klapötke T. M.

Central European Journal of Energetic Materials

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2015

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Vol. 12, no. 3

403--416

EN

This study presents the preparation of 1-(5-azido-1H-1,2,4-triazol-3yl)tetrazole (5) from commercially available chemicals in a five step synthesis. The energetic title compound was comprehensively characterized by various means, including vibrational (IR, Raman) and multinuclear (1H, 13C, 14N, 15N) NMR spectroscopy, mass spectrometry and differential scanning calorimetry. The sensitivities towards various outer stimuli (impact, friction) were determined according to BAM standards. The enthalpy of formation was calculated at the CBS-4M level of theory.

6

Highly Energetic Salts of 3,6-Bishydrazino-1,2,4,5-tetrazine

Klapötke T. M., Preimesser A., Schedlbauer S., Stierstorfer J.

Central European Journal of Energetic Materials

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2013

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Vol. 10, no. 2

151--170

EN

3,6-Bishydrazino-1,2,4,5-tetrazine was synthesized as described by hydrazinolysis of 3,6-bis-(3,5-dimethylpyrazolyl)-1,2,4,5-tetrazine. Doubly protonated 1:1 and 1:2 salts of the highly energetic anions were synthesized. These are bishydrazinium-tetrazine dichloride dihydrate (1:2) (BHT-2HCl•2H2O) (2), bishydrazinium-tetrazine (5,5´-azotetrazolate) dihydrate (1:1) (BHT-ATz•2H2O) (3), bishydrazinium-tetrazine bis (3,5-dinitrotriazolate) dihydrate (1:2) (BHT(DNT)2•2H2O) (4), bishydrazinium-tetrazine bis (5-nitrotetrazolate) (1:2) (BHT(NT)2) (5), bishydrazinium-tetrazine (5,5´-bistetrazolate) dihydrate (1:1) (BHTBT•2H2O) (6), bishydrazinium-tetrazine bistetrazolylamine (1:1) (BHT-BTA) (7), bishydrazinium-tetrazine bis (3-amino-5-nitrotriazolate) (1:2) (BHT-(ANTA)2) (8) and bishydrazinium-tetrazine 4,4´,5,5´-tetranitro-2,2´-bisimidazolate (1:1) (9). Compounds 2-6 could be characterized by low temperature X-ray diffraction. All of the compounds were suffciently analyzed by 1H and {1H}13C and 14N NMR spectroscopy, elemental analysis (CHN), mass spectroscopy (FAB)) and vibrational spectroscopy (IR and Raman). The detonation parameters of the most promising candidates 5 and 9 in terms of energetic applications were calculated using the EXPLO5 V5.05 computer code. The energies of formation were calculated using CBS-4M electronic enthalpies and the atomization method. Furthermore, since all of the compounds are energetic materials, sensitivity tests towards impact (IS), friction (FS) and electrostatical discharge (ESD) were carried out. In addition their thermal stabilities were determined using a differential scanning calorimeter with a heating rate of 5 °C min-1.

7

Energetic Nitrogen-Rich Polymers Based on Cellulose

Betzler F. M., Klapötke T. M., Sproll S.

Central European Journal of Energetic Materials

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2011

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Vol. 8, nr 3

157-171

EN

New nitrogen-rich polymers, based on cellulose, were synthesized using common procedures. The point of interest was the introduction of tetrazole and nitramine moieties. The polymers were characterized by elemental analysis and vibrational spectroscopy (IR). The energetic properties were investigated using differential scanning calorimetry and bomb calorimetric measurements. Several detonation parameters, such as the detonation pressure, velocity, energy and temperature were computed using the EXPLO5 code. In addition, the sensitivities towards impact and friction were tested using the BAM drophammer as well as a friction tester.

8

5,5'-Dinitrimino-3,3'-methylene-1H-1,2,4-bistriazole - a Metal Free Primary Explosive Combining Excellent Thermal Stability and High Performance

Dippold A. A., Feller M., Klapötke T. M.

Central European Journal of Energetic Materials

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2011

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Vol. 8, nr 4

261-278

EN

The synthesis of 5,5´-dinitrimino-3,3'-methylene-1H-1,2,4-triazole (1) and selected nitrogen rich salts are presented. All compounds were fully characterized in terms of sensitivity and energetic properties. Besides a chemical characterization including multinuclear magnetic resonance study (1H, 13C, 14N) and vibrational analysis (IR, Raman), X-Ray diffraction was performed. Thermal stability was determined using differential scanning calorimetry. Detonation parameters were calculated using the EXPLO5.4 code based on CBS-4M computed heats of formation. The presented compound 5,5´-dinitrimino-3,3´-methylene- 1H-1,2,4-bistriazole shows excellent thermal stabilities in combination with high sensitivities and therefore is of interest for possible applications as metal free primary.

9

Nanoscale Aluminum - Metal Oxide (Thermite) Reactions for Application in Energetic Materials

Piercey D. G., Klapötke T. M.

Central European Journal of Energetic Materials

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2010

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Vol. 7, nr 2

115-129

EN

Energetic materials fnd use in both military and civilian applications, however many commonly used materials suffer from serious defciencies including toxicity and high sensitivity. Nanothermites exhibit vastly differing characteristics compared to their well known micron scale relatives and through the use of various preparatory chemical techniques can be tailored to have a wide spectra of chemical and energetic properties. This may allow use as superior replacements of conventional energetic materials in various applications.

10

Less Sensitive Transition Metal Salts of the 5-Nitrotetrazolate Anion

Klapötke T. M., Sabaté C. M.

Central European Journal of Energetic Materials

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2010

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Vol. 7, nr 2

161-173

EN

Transition metal (silver and copper) salts of the 5-nitrotetrazolate (NT) anion (1 and 2) have been synthesized and characterized by analytical and spectroscopic methods. Standard BAM tests revealed extremely high sensitivity values for these compounds. The combination with the ethylenediamine ligand in salts 3 and 4 decreases the sensitivities in comparison to salts 1 and 2 making for much less hazardous handling and rendering the synthesis of NT salts more accessible for up-scaling. Additionally, a copper ammonia adduct of the NT anion (5) was synthesized, which shows the particularity of being able to be initiated by a laser beam, thus, decreasing the risk of accidental initiation, which often accompanies the use of primary explosives.

11

5-Aminotetrazoles and Silver-based Primary Explosives

Delalu H., Karaghiosoff K., Klapötke T. M., Miró Sabaté C.

Central European Journal of Energetic Materials

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2010

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Vol. 7, nr 3

197-216

EN

Several silver nitrate and perchlorate salts with 5-aminotetrazole-based ligands have been synthesized and characterized by elemental analysis, mass spectrometry, IR, Raman and multinuclear NMR spectroscopy. In addition, several of the new compounds were characterized by X-ray structure analysis. The energetic properties of the materials were assessed by differential scanning calorimetry (DSC) analysis in combination with standard impact and friction BAM tests. The compounds synthesized have good thermal stabilities above 225 C and in some instances the high sensitivities of the materials towards impact and friction make them fall under the category of primary explosives. Some of the compounds might present prospective use in initiation devices for civil and military applications.

12

Primary Nitramines Related to Nitroglycerine: 1-Nitramino-2,3-dinitroxypropane and 1,2,3-Trinitraminopropane

Altenburg T., Klapötke T. M., Penger A.

Central European Journal of Energetic Materials

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2009

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Vol. 6, nr 3-4

255-275

EN

The title compounds 1-nitramino-2,3-dinitroxypropane (NG-N1) and 1,2,3-trinitraminopropane (NG-N3) were formed by multi-step reaction from the corresponding amine. Both compounds were fully characterized by means of multinuclear NMR (1 H, 13 C, 14 N) N), vibrational spectroscopy, elemental analysis and mass spectrometry. For prediction of the energetic properties ΔHc values are determined by oxygen bomb calorimetry and validated by quantum theoretical methods. Both compounds are superior in their performance data to nitroglycerine (NG) and pentaerythritol tetranitrate (PETN). In comparison to nitroglycerine the sensitivities towards mechanical stimuli is greatly reduced. X-ray diffraction elucidated the molecular structure of both compounds. NG-N1 crystallizes in the monoclinic space group P21 with a density of 1.799 g/cm(3), NG-N3 in the orthorhombic space group Pnma with a density of 1.783 g/cm(3). The thermal behavior and long term stabilities were checked using differential scanning calorimetry and thermogravimetric measurements. NG-N1, shows for primary nitramines, exceptional stability in the molten phase making this compound suitable for melt-cast application (Tmp: 65 C, Tdec: 170 C).

13

Synthesis and Characterization of the Energetic Compounds Aminoguanidinium-, Triaminoguanidiniumand Azidoformamidinium Perchlorate

Klapötke T. M., Stierstorfer J.

Central European Journal of Energetic Materials

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2008

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Vol. 5, nr 1

13-30

EN

Aminoguanidinium perchlorate (2, AGClO4) was formed by the reaction of aminoguanidinium bicarbonate (1) with aqueous perchloric acid solution. Triaminoguanidinium perchlorate (3, TAGClO4) was synthesized by nucleophilic attack of aqueous hydrazine solution on aminoguanidinium perchlorate under release of ammonia. The new and highly explosive azidoformamidinium perchlorate (4, AFClO4) was formed by the reaction of aminoguanidinium perchlorate with potassium nitrite under acidic conditions. The structures of the perchlorate salts in the crystalline state were determined using low temperature single crystal X-ray diffraction yielding monoclinic as well as orthorhombic structures. The compounds were characterized comprehensively using vibrational spectroscopy (IR and Raman), multinuclear (1H, 13C and 15N) NMR spectroscopy, elemental analysis and mass spectrometry. The thermal behavior as well as the decompositions were investigated using DSC (differential scanning calorimetry) and the heats of formation were calculated using heats of combustion determined by bomb calorimetric measurements. In addition, the sensitivities were evaluated using BAM methods (drophammer and friction tester), whereby the perchlorate salts are all sensitive towards impact as well as friction.

14

Hydrazinium 5-Aminotetrazolate: an Insensitive Energetic Material Containing 83.72% Nitrogen

Fischer N., Klapötke T. M., Scheutzow S., Stierstorfer J.

Central European Journal of Energetic Materials

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2008

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Vol. 5, nr 3-4

3-18

EN

Hydrazinium 5-aminotetrazolate (2) was synthesized via two facile routes. Both the reaction of 5-amino-1H-tetrazole (1) with hydrazine hydrate in aqueous solution and the reaction of 1 with diluted hydrazine solution in THF yield 2 in excellent purities and yields. 2 was characterized comprehensively by X-ray diffraction, IR, Raman and multinuclear NMR spectroscopy, mass spectrometry, elemental analysis and differential scanning calorimetry. The heat of formation was calculated (CMS-4M) using the atomization method to be 373 kJ mol-1. With this value and the X-ray density several detonation parameter (heats of explosion, detonation pressure, detonation velocity, explosion temperature) were calculated with the EXPLO5 computer software. An incredible high value (9516 m s-1) was obtained for the detonation velocity. Therefore experimentally tests to determine the velocity of detonation were performed. In addition the use of 2 in solid propellant compositions was calculated and tested in combination with oxidizers, e.g. ammonium dinitramide. Lastly the sensitivities towards impact, friction and electrostatic discharge were determined with the BAM drophammer, friction tester and an ESD machine.

15

The Elimination of NO2 from Mixtures of the Nitramines HMX, RDX and CL20 with the Energetic Binder Glycidyl Azide Polymer (GAP) - A Computational Study I

Bohn M. A., Hammerl A., Harris K., Klapötke T. M.

Central European Journal of Energetic Materials

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2005

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Vol. 2, nr 2

29-44

EN

The energetic plasticizer glycidyl azide polymer (GAP) is used for new types of rocket propellants which are formulated with the objective of achieving higher burning rates. The reaction profiles for several possible initial steps in the decomposition of mixtures of the nitramines octahydro-1,3,5,7-tetranitro-1,3,5,7- tetrazacyclooctane (HMX), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and hexanitrohexaazaisowurtzitane (CL20) with a monomer of GAP-diol have been examined computationally. Comparison of the activation energies for the decomposition of the mixtures with those for the decomposition of the isolated nitramines shows that the presence of GAP-diol decreases the activation energy for the elimination of NO2 by at least to 8 kJ mol-1 for CL20, wheras the NO2 elimination from HMX is only favored by 1 kJ mol-1 and NO2 elimination from RDX is inhibited in the presence of GAP-diol by 2 kJ mol-1.

16

Further Decomposition Pathways of Mixtures of the Nitramines HMX, RDX and CL20 with the Energetic Binder Glycidyl Azide Polymer (GAP) - A Computational Study II

Bohn M. A., Hammerl A., Harris K., Klapötke T. M.

Central European Journal of Energetic Materials

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2005

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Vol. 2, nr 3

3-19

EN

The energetic plasticizer glycidyl azide polymer (GAP) is used for new types of rocket propellants which are formulated with the objective of achieving higher burning rates. While the homolytic fission of an N-NO2 bond, which we discussed previously, is energetically favored as the initial decomposition step, experiments show that the decomposition of mixtures of the nitramines octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazacyclooctane (HMX), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and hexanitrohexaazaisowurtzitane (CL20) with a monomer of GAP-diol is more complex. Therefore we investigated further possible decomposition pathways. Comparison of the calculated activation energies for the decomposition of the mixtures with those for the decomposition of the isolated nitramines shows that the presence of GAP-dioldecreases the activation energies of certain decomposition steps by up to 20 kJ mol-1. GAP-diol facilitates the decomposition of CL20 and RDX to a larger extent than the decomposition of HMX. However, the investigated decomposition pathways of GAP-diolwere inhibited by the presence of the nitramines.