Synthesis and Investigation of Energetic Boron Compounds for Pyrotechnics

Abstract

The energetic boron esters tris(1-ethyl-5-aminotetrazolyl) borate, tris(2-ethyl-5-aminotetrazolyl) borate, tris(1-ethyltetrazolyl) borate, tris(2-ethyltetrazolyl) borate, and tris(2-(3-nitro-1,2,4-triazolyl)ethyl) borate were synthesized and analyzed by NMR and IR spectroscopy, elemental analysis, and mass spectrometry. Two tetracoordinate borates potassium tetrakis(3-nitro-1,2,4-triazolyl)borate and potassium bis(4,4Ј,5,5Ј-tetranitro-2,2Ј-bisimidazolyl)borate were synthesized and fully characterized as well. Moreover, the energetic and * Prof. Dr. T. M. Klapötke

Bis(thiocarbamates): Synthesis and Substituent Effects on the Barrier to N‐CO Rotation

“…As in the case of amides [29][30][31][32] and carbamates [32][33][34][35][36]45,50], bis(thiocarbamates) are characterized by the presence of N-CO bond having a partially double bond character, which results in the presence of the two s-cis and s-trans conformations. In our case and as can be seen from Table 1, the benzyl and phenyl derivatives show the coexistence of the two conformers (i.e., two NH NMR signals), while only one signal was observed in the 1 H NMR spectra for the other derivatives at room temperature (Fig.…”

“…Recently, the synthesis of polythiourethanes has shown an increasing expansion primarily due to their successful industrial and commercial applications as high refractive index optical materials [29][30][31][32]. Despite the enormous work carried out on polyurethane and polythiourethane [23][24][25][26][27][28][29], studies on monomer analogs (i.e., urethanes or diurethanes) are much less reported in the literature [33][34][35]. This seems to be surprising since investigation of the structure and properties of the latter simple molecules would be much easier before polymerization than that undertaken on the more complicated polymer counterparts.…”

Advances Toward the Development of “Green” Pyrotechnics

“…Though not an environmentally friendly formulation by today's standards, an early barium-free green-light emitting formulation, consisting of 30% B/60% KClO 4 /10% lactose, was investigated by Eppig in the late stages of World War II in Germany as a replacement for barium chlorate-based formulations [47]. The combustion amorphous boron in the presence of potassium nitrate (B/KNO 3 ) is a widely known method of generating green light, and Rusan and Klapötke have produced smokeless green flames through the combustion of NH 4 NO 3 /B/boron-based high-nitrogen/VAAR mixtures [48]. The sensitivities of amorphous boron-based mixtures to ignition stimuli can sometimes be a concern, however, and amorphous boron is also a fairly expensive material.…”

“…The reduction in spectral purity of formulation 12 can likely be traced to a substantial amount of continuum emission based on potassium hydroxide (KOH), resulting in white light and a "washing out" of the perceived green color. The use of metal-free oxidizers such as ammonium nitrate, as done by Rusan and Klapötke [48], would likely aid in increasing the spectral purity of formulation 12, though it is likely that this approach will also affect the burn time and light output significantly.…”

Color‐Changing Sparks from Rare Earth Metal Powders

“…Consequently, even elements with higher boiling points than erbium may provide element-specifically emitting stages. Jennings-White gives a survey on potential candidates for pyrotechnic applications throughout the periodic Table [12] and recent examples include boron, [13][14][15] cesium compounds, [16,17] copper iodide [18] and copper complexes [19] as well as copper-based blue strobe compositions, [20,21] new formulations based on lithium, [22,23] and sodium salts, [24] detailed investigations of composition based on barium [25] and strontium [26] salts as well as calcium [27] and strontium tetrazolates, [28] and indium [29] metal. Typical radiation trace of sparks based on different burning stages given in literature [11] and element-specific colored stage observed for erbium.…”