TKX-50

  1. Home
  2. Wiki
TKX-50
Names
IUPAC name
Dihydroxylammonium-5,5′-bistetrazolyl-1,1′-diolate
Other names
Dihydroxylammonium-5,5′-bistetrazolyl-1,1′-diolate, Dihydroxylammonium-5,5′-bistetrazolyl-1,1′-dioxide,
Identifiers
3D model (JSmol)
  • InChI=1S/C2N8O2.2H4NO/c11-9-1(3-5-7-9)2-4-6-8-10(2)12;2*1-2/h;2*2H,1H3/q-2;2*+1
    Key: UHTGTYVZCBKFMU-UHFFFAOYSA-N
  • [NH3+]O.[NH3+]O.[O-]N1N=NN=C1C2=NN=NN2[O-]
Properties
C2H8N10O4
Molar mass 236.15 g/mol
Appearance colorless crystals
Density 1.92 g/cm3
Explosive data
Shock sensitivity 20 J
Friction sensitivity 120 N
Detonation velocity 9698 m/s
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

TKX-50 is the chemical compound with the formula C2H8N10O4. It is a hydroxylammonium salt of 5,5′-bistetrazolyl-1,1′-diolate. It forms colorless crystals. It is a high-performing explosive with performances higher than RDX and HMX while being safer towards mechanical stimuli. It is also considered an environmentally-friendly replacement for several conventional explosives.[1][2] As of 2014, the US Army was preparing it in 20 kg batches in order to evaluate it as an explosive.[3] It was invented by Niko Fischer, Dennis Fischer, Davin G. Piercey, Thomas M. Klapötke and Jörg Stierstorfer in the research group of Thomas M. Klapötke at the Ludwig Maximilians-Universität München.[4] Its development was funded by the Ludwig-Maximilian University of Munich (LMU), the U.S. Army Research Laboratory (ARL), the Armament Research, Development and Engineering Center (ARDEC), the Strategic Environmental Research and Development Program (SERDP) and the Office of Naval Research (ONR).

Synthesis

[edit]

The compound is prepared by reacting 5,5′-bistetrazolyl-1,1′-diol (BTO) with hydroxylamine. The starting compound BTO can be obtained relatively easily from glyoxal, hydroxylamine, chlorine, and sodium azide.[5] [6]

TKX-50 synthesis

Since the initial synthesis of TKX-50 multiple research groups have improved the synthesis to make it more suitable for mass production including by adding protecting groups to make intermediates safer[7] and the United States Army Research Laboratory by performing multiple steps of the synthesis in a 1-pot reaction.[8]

Characteristics

[edit]

TKX-50 is a crystalline solid with no melting point. The compound occurs in two polymorphic crystal forms. At about 180 °C, a second-order phase transition with a small heat capacity change of about 0.3 J Mol−1·K−1is observed, resulting in a transformation from the low-temperature to a high-temperature crystal form. The crystal system changes from monoclinic with the space group P 2 1 /c to triclinic with the space group P 1.[9] The compound is thermally unstable. DSC measurements show an exothermic decomposition reaction above 215 °C with a latent heat of decomposition of −2200 kJ kg −1 and −520 kJ mol −1, respectively.[10][11] The standard enthalpy of formation based on combustion calorimetry measurements is 473 kJ mol−1.[12]

Explosive uses

[edit]

TKX-50 has been found to lead to melt-cast formulations with higher performance than those with HMX.[13]

References

[edit]
  1. ^ D. M. Badgujar, M. B. Talawar, P. P. Mahulikar (2017), "Review of Promising Insensitive Energetic Materials", Central European Journal of Energetic Materials, vol. 14, no. 4, pp. 821–843, doi:10.22211/cejem/68905{{citation}}: CS1 maint: multiple names: authors list (link)
  2. ^ "Safer Explosives Still Pack a Punch". 21 January 2025.
  3. ^ "Boom!".
  4. ^ Niko Fischer, Dennis Fischer, Thomas M. Klapötke, Davin G. Piercey, Jörg Stierstorfer (2012), "Pushing the limits of energetic materials – the synthesis and characterization of dihydroxylammonium 5,5′-bistetrazole-1,1′-diolate", Journal of Materials Chemistry, vol. 22, no. 38, pp. 20418–20422, doi:10.1039/C2JM33646D{{citation}}: CS1 maint: multiple names: authors list (link)
  5. ^ Fischer, N.; Klapötke, T.M.; Reymann, M.; Stierstorfer, J.: Nitrogen-Rich Salts of 1H,1'H-5,5'-Bitetrazole-1,1'-diol: Energetic Materials with High Thermal Stability in Eur. J. Inorg. Chem. 2013, 2167–2180, doi:10.1002/ejic.201201192.
  6. ^ US patent 9296664, Thomas M. Klapötke, Niko Fischer, Dennis Fischer, Davin G. Piercey, Jörg Stierstorfer, Marius Reymann, "Energetic active composition comprising a dihydroxylammonium salt or diammonium salt of a bistetrazolediol", issued 2016-03-29 
  7. ^ Kwon, K.; Kim, S.; Lee, S.; Lee, W. H.: Safe and Scale-up-friendly Synthesis of TKX-50 in Propellants Explos. Pyrotech. 2025, e12073, doi:10.1002/prep.12073.
  8. ^ US patent 9643937B1, Reddy Damavarapu, Raja Duddu, "One-pot process for preparation of ammonium and hydroxyl ammonium derivatives of bis 5,5′-tetrazole-1,1′-dihydroxide", issued 2017-05-09 
  9. ^ Zhipeng Lu, Xianggui Xue, Liya Meng, Qun Zeng, Yu Chi, Guijuan Fan, Hongzhen Li, Zengming Zhang, Fude Nie, Chaoyang Zhang: Heat-Induced Solid−Solid Phase Transformation of TKX-50 in J. Phys. Chem. C 121 (2017) 8262–8271, doi:10.1021/acs.jpcc.7b00086.
  10. ^ Hu Niu, Shusen Chen, Qinghai Shu, Lijie Li, Shaohua Jin (2017-09-15), "Preparation, characterization and thermal risk evaluation of dihydroxylammonium 5, 5′-bistetrazole-1, 1′-diolate based polymer bonded explosive", Journal of Hazardous Materials, vol. 338, pp. 208–217, doi:10.1016/j.jhazmat.2017.05.040, PMID 28558326{{citation}}: CS1 maint: multiple names: authors list (link)
  11. ^ Dilip Badgujar, Mahadev Talawar (2017), "Thermal and Sensitivity Study of Dihydroxyl Ammonium 5,5′-Bistetrazole-1,1′-diolate (TKX-50)-based Melt Cast Explosive Formulations", Propellants, Explosives, Pyrotechnics, vol. 42, no. 8, pp. 883–888, doi:10.1002/prep.201600168
  12. ^ D. Fischer, V. Golubev, T. M. Klapötke, J. Stierstorfer: Synthesis and Characterization of Novel High-Nitrogen Secondary Explosives. In: Tagungsband die 21. Kalorimetrietage : Braunschweig, 27.-29. Mai 2015 / Veranstalter Gesellschaft für Thermische Analyse e. V., Physikalisch-Technische Bundesanstalt. ISBN 978-3-944659-02-2 (Abstract).
  13. ^ Yu, Y.; Chen, S.; Li, T.; Jin, S.; Zhang, G.; Chen, M.; Li, L.: Study on a novel high energetic and insensitive munitions formulation: TKX-50 based melt cast high explosive in RSC Advances 2017, 31485-31492, doi:10.1039/C7RA05182D.