Synthesis and Characterization of New Energetic Nitroformate Salts

Abstract

New energetic nitroformate salts that contain high‐nitrogen cations were synthesized by taking advantage of the relatively high acidity of nitroform. All of the new salts have been characterized by elemental, spectral, and thermal analyses. Single‐crystal X‐ray analysis of 2 shows that it is a co‐crystal of a neutral 4‐amino‐1,2,4‐triazole molecule with the 4‐amino‐1,2,4‐triazolium nitroformate ion pair. The presence of the neutral molecule appears to lend stability to the salt. The structure of 3,6‐diguanidino‐1,2,4,5‐tetrazinium nitroformate (10) was also confirmed by single‐crystal X‐ray analysis. Theoretical performance calculations indicate that these materials have properties which compare favorably with hydrazinium nitroformate, TNT and Tetryl suggesting potential applications as eco‐friendly oxidizers. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)

1,2,4‐Triazolium‐Cation‐Based Energetic Salts

“…[24] The triazolium ring is planar, with the exocyclic nitrogen atoms lying in this plane. The tetrahedral geometry and bond length (N1ÀN4 % 1.40 ) of the nitrogen-bound (N4) amino group indicates little interaction of the nitrogen lone-pair and the triazolium-ring p system, similar to other triazolium species, [9,19,31,45] and as predicted by theoretical studies on N-aminoazoles, which led to the conclusion that sp 3 hybridisation for N À NH 2 groups is preferred over sp 2 hybridisation. [46] On the other hand, the carbon-bound amino groups (N5 and N6) have angles close to 1208, corresponding to a sp 2 hybridisation, and the C1ÀN6 and C3ÀN5 distances are in the range 1.317(4)-1.330(3) and 1.332(3)-1.357(2) , respectively.…”

“…[1][2][3][4][5][6][7] There are several criteria that new highenergy density materials (HEDMs) should meet [8] in order to be considered as feasible replacements for currently known energetic compounds, such as hexahydro-1,3,5-tri-A C H T U N G T R E N N U N G nitro-1,3,5-triazine (RDX), trinitrotoluene (TNT) or pentaerythritol tetranitrate (PETN). Ideally, new compounds should have detonation parameters (e.g., velocity) comparable to those of known widely used high explosives (e.g., D RDX % 8800 m s À1 ), [9] good thermal stabilities of at least 200 8C, they should be hydrolytically stable with shelf lives longer than 15 years, be compatible with binders and/or plasticisers, insensitive to friction (> 7 J) and shock A C H T U N G T R E N N U N G (>120 N), have low (no) solubility in water, the decomposition products should be environmentally benign and the yield for their synthesis should be high and the price low. The performance of an energetic material is mainly a function of the density of the compound, its oxygen coefficient and its heat of formation; all three parameters are governed by its molecular structure.…”

Crystal structures, thermal decompositions and sensitivity properties of [Cu(ethylenediamine)2(nitroformate)2] and [Cd(ethylenediamine)3](nitroformate)2

“…However, the application of nitroform is severely constrained for its strong acidity and low decomposition temperature which is 298 K. Therefore, nitroform needs to cooperate with other compounds to form novel stable substances. Nitroformate salts have been widely studied [2][3][4][5][6][7][8][9][10][11][12]. For instance, hydrazinium nitroformate is a promising energetic oxidizer used to replace ammonium perchlorate in rocket propellant [13][14][15][16].…”

[BH3C(NO2)3]−: The First Room‐Temperature Stable (Trinitromethyl)borate

“…[18] None of the salts, PPh 4 À salt which, by analogy with naked sodium nitroformate, might possess only marginal stability at room temperature. [5] The lower stability of alkalimetal salts compared to salts containing bulky cations, such as PPh 4 + and PNP + , is common and has been observed by us for many polyazido salts. [19] The very slow decomposition of solid PPh 4 [BH 3 C(NO 2 ) 3 ] and PNP[BH 3 C(NO 2 ) 3 ] at room temperature contrasts with the differential thermal analysis (DTA) results, which show that the compounds seem to be thermally stable up to approximately 120 8C.…”

“…[2d, [5][6][7] In view of the relatively high average bond energy of BÀC bonds (ca. 89 kcal mol À1 ), [8] (trinitromethyl)borates can be expected to be stable compounds.…”