Kinetics of the thermal decomposition of dinitramide

The kinetic regularities of the thermal decomposition of dinitramide in aqueous solutions of HNO₃, in anhydrous acetic acid, and in several other organic solvents were studied. The rate of the decomposition of dinitramide in aqueous HNO₃ is determined by the decomposition of mixed anhydride of dinitramide and nitric acid (N₄O₆) formed in the solution in the reversible reaction. The decomposition of the anhydride is a reason for an increase in the decomposition rates of dinitramide in solutions of HNO₃ as compared to those in solutions in H₂SO₄ and the self-acceleration of the process in concentrated aqueous solutions of dinitramide. The increase in the decomposition rate of nondissociated dinitramide compared to the decomposition rate of the N(NO₂)₂ ⁻ anion is explained by a decrease in the order of the N−NO₂ bond. The increase in the rate constant of the decomposition of the protonated form of dinitramide compared to the corresponding value for neutral molecules is due to the dehydration mechanism of the reaction. For Part 1, see Ref. 1. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 41–47, January, 1998.     

Decomposition of aminotetrazole based energetic materials under high heating rate conditions

A T-jump/time-of-flight mass spectrometer (T-Jump/TOFMS) is used to probe the decomposition of several aminotetrazole containing energetic materials under very high heating rates of 10(5)-10(6) K/s. The materials investigated are 5-amino-1-methyl-1H-tetrazolium dinitramide (MeHAT_DN), 1,5-diamino-4-methyl-1H-tetrazolium dinitramide (MeDAT_DN), 1,5-diamino-1H-tetrazolium nitrate (DAT_N), 1,5-diamino-4-methyl-1H-tetrazolium azide (MeDAT_N3), and 5-aminotetrazolium dinitramide (HAT_DN). Subtle differences between materials in functional group placement and anion composition allow for further understanding of the decomposition pathway of the tetrazole structure and various anions. Two decomposition pathways for the tetrazole ring are observed, which result in the primary formation of HN(3) or N(2). The N(2) formation pathway occurs when functional groups are placed symmetrically around the tetrazole ring, whereas asymmetric placement results in HN(3) production. The differing anion compositions also show effects on thermal stability of the salts, as is demonstrated by a lower decomposition temperature for the azide containing salt compared to the similar dinitramide containing material. For the decomposition of the dinitramide molecule, high temperature (N(2)O forming) and low temperature (NO(2) forming) decomposition pathways are observed, as has been previously suggested.     

Oxygen versus nitrogen interactions in lithium dinitramidate dihydrate and pyridinium dinitramidate

The title compounds, diaquadinitramidatolithium(I), [Li(N₃O₄)(H₂O)₂], (I), and pyridinium dinitramidate, C₅H₆N⁺·N₃O₄⁻, (II), differ significantly in their cation–anion contacts. The Li⁺ atom of (I) is coordinated by two O atoms of the dinitramide anion in a chelate and by four additional water molecules, with the Li and central N atom of the anion on a twofold rotation axis. The pyridinium cation of (II) exhibits a contact with the dinitramide anion via an intermolecular N—H...N hydrogen bridge. These interactions are compared with those found in reported anhydrous lithium dinitramide and ammonium dinitramide salts.     

Triaminoguanidinium dinitramide-calculations, synthesis and characterization of a promising energetic compound

The highly energetic compound 1,3,5-triaminoguanidinium dinitramide (1) was prepared in high yield (82%) according to a new synthesis by the reaction of potassium dinitramide and triaminoguanidinium perchlorate. The heat of formation was calculated in an extensive computational study (CBS-4M). With this the detonation parameters of compound were computed using the EXPLO5 software: D = 8796 m s(-1), p = 299 kbar. In addition, a full characterization of the chemical properties (single X-ray diffraction, IR and Raman spectroscopy, multinuclear NMR spectroscopy, mass spectrometry and elemental analysis) as well as of the energetic characteristics (differential scanning calorimetry, thermal safety calorimetry, impact, friction and electrostatic tests) is given in this work. Due to the high impact (2 J) and friction sensitivity (24 N) several attempts to reduce these sensitivities were performed by the addition of wax. The performance of was tested applying a "Koenen" steel sleeve test resulting in a critical diameter of > or =10 mm.     

Stabilization of ammonium dinitramide in the liquid phase

The kinetics of accumulation of the main products of thermal decomposition of ammonium dinitramide in the melt was investigated. The isotope composition of nitrogen-containing gases evolved by the decomposition of ¹⁵NH₄N(NO₂)₂ and NH₄ ¹⁵N(NO₂)₂ was found. Easily oxidized salts, amines, amides, iodides, and other compounds soluble in the melt interfere with the liquid-phase decomposition of ammonium dinitramide.     

Oxidative nucleophilic substitution reaction of alkyl iodides upon treatment with perchlorate and dinitramide anions. Synthesis of alkyl-substituted perchlorates

Reactions of oxidative nucleophilic substitution of alkyl iodides with lithium perchlorate and dinitramide were studied. The reactions of alkyl iodides and lithium perchlorate, proceeding in the presence of nitronium tetrafluoroborate as an oxidant, furnished a series of new alkyl perchlorates, including those containing an adamantyl fragment. Spectral properties of alkyl perchlorates were studied in detail for the first time. The reactions of oxidative nucleophilic substitution of iodoacetic ester and lithium dinitramide, proceeding upon treatment with nitronium tetrafluoroborate or ozone, resulted in the substitution of an iodine atom with the nitrate anion.     

Sputtered ammonium dinitramide: Tandem mass spectrometry of a new ionic nitramine

The recently synthesized ammonium dinitramide (ADN) is an ionic compound containing the ammonium ion and a new oxide of nitrogen, the dinitramide anion (O₂N? N? NO₂^?). ADN has been investigated using high-energy xenon atoms to sputter ions directly from the surface of the neat crystalline solid. Tandem mass spectrometric techniques were used to study dissociation pathways and products of the sputtered ions. Among the sputtered ionic products were NH₄⁺, NO⁺, NO₂^?, N₂O₂^?, N₂O, N₃O₄^? and an unexpected high abundance of NO₃^?. Tandem mass spectra of the dinitramide anion reveal the uncommon situation where a product ion (NO₃^?) is formed in high relative abundance from metastable parent ions but is formed in very low relative abundance from collisionally activated parent ions. It is proposed that the nitrate anion is formed in the gas phase by a rate-determining isomerization of the dinitramide anion that proceeds through a four-centered transition state. The formation of the strong gas-phase acid, dinitraminic acid (HN₃O₄), the conjugate acid of the dinitramide anion, was observed to occur by dissociation of protonated ADN and by dissociation of ADN aggregate ions with the general formula [NH₄(N(NO₂)₂)_n] NH₄⁺, where n = 1–30.     

Dinitramide and its salts

A strategy of organic synthesis has been developed for a new class of inorganic compounds,viz., dinitramide and its metal, ammonium, and substituted ammonium salts. The basic concepts have been tested in model reactions of -substituted derivatives ofN-alkyl-N-nitrotoluenesulfonamides with bases and have been confirmed by the decyanoethylation ofN,N-dmitro--aminopropionitrile taken as an example.In the communications of this series, we are going to report the results of work on dinitramide carried out in 1970–1980 that could not be published previously. The synthesis of dinitramide salts was first published in the patent literature in 1992. 1,2Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 94–97, January, 1994.     

Anomalous decomposition of dinitramide metal salts in the solid phase

Unusual regularities are observed for decomposition of dinitramide metal salts in the solid phase: the solid-phase reaction is 10–10³ times faster than that in the melt, its rate has a sharp peak in the region of eutectics melting with the decomposition product (metal nitrate), and it is instantly inhibited by water vapor. In the inhibited regime, the rate in the solid phase is lower than that in the liquid phase. No indications of this anomalous behavior are observed for the decomposition of the dinitramide guanidinium salt. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1947–1950, November, 1997.     

Dinitramide and its salts

Nitration of nitramidc to dinitramide with nitryl salts is described.     

Oxidative nitration of the amino group: synthesis of dinitramide and cyanonitramide salts

A convenient preparative method for the synthesis of potassium dinitramide and cyanonitramide salts was developed. The method involves reactions of nitramide or cyanamide with KNO₂ and PhI(OAc)₂ or PhIO in methanol.     

A novel energetic nickel coordination compound based on carbohydrazide and dinitramide

Dinitramide was reacted with carbohydrazide to furnish the corresponding mono- and bis-susbtituted salts. The nickel salt of dinitramide when reacted with carbohydrazide produced the coordination compound, tris(carbohydrazide- N,O)nickel(ii) bis-dinitramide, whose crystal structure was characterized by X-ray diffraction.     

Thermal behavior of ammonium dinitramide and amine nitrate mixtures

Journal of Thermal Analysis and Calorimetry - This paper focuses on the thermal behavior of mixtures of ammonium dinitramide (ADN) and amine nitrates. Because some mixtures of ADN and amine nitrate...     

Synthesis and Characterization of a New Energetic Salt based on Dinitramide

The development of new ionic salt as green propellants is one of intense investigations to replace toxic N, N′‐dimethylhydrazine. A new energetic salt N, N′,N′′‐tri(propan‐2‐ylidene)methanetriamium dinitramide (NTAGDN) based on dinitramide was synthesized by reacting silver dinitramide with triaminoguanidinium chloride. The structure of this new energetic salt was confirmed by single‐crystal X‐ray diffraction, elemental analysis, Fourier transform infrared spectrometry, ultraviolet‐visible spectrophotometry, and nuclear magnetic resonance spectroscopy. NTAGDN crystallizes in the orthorhombic space group R$\bar{3}$ . Thermal decomposition was studied by differential scanning calorimetry, differential thermal analysis, and thermogravimetric tandem infrared spectrometry. Results indicated that NTAGDN exhibited excellent resistance to thermal decompositions of up to 470 K and incurred an 80.54 % mass loss between 450 and 523 K via exothermic decomposition. The kinetic parameters of NTAGDN thermal decomposition were also obtained from the differential thermal analysis data by Kissinger's method with E_a = 125.46 kJ · mol^–1. Moreover, based on the Kamlet‐Jacobs formula, the detonation velocity and detonation pressure of NTAGDN were calculated as 6.3 km · s^–1 and 15 GPa, respectively.     

Energetic potential of solid composite propellants based on CL-20-containing bimolecular crystals

The energetic potential of bimolecular crystals (BMCs) containing CL-20 as components of solid composite propellants (SCPs) was investigated. The experimental and calculated values of the standard enthalpies of formation are reported. The maximum heats of explosion, which correlate with the impact sensitivity, were calculated. The specific impulse values and the densities of SCPs based on an active binder, aluminum, and oxidizer (BMC + a small portion of ammonium dinitramide) were evaluated.     

Synthesis and Characterization of 3,5‐Diamino‐1,2,4‐triazolium Dinitramide

3,5‐Diamino‐1,2,4‐triazole ( 1 , guanozol) was protonated with diluted hydrochloric acid, nitric acid, as well as perchloric acid forming 3,5‐diamino‐1,2,4‐triazolium chloride hemihydrate ( 2 ), 3,5‐diamino‐1,2,4‐triazolium nitrate ( 3 ) and 3,5‐diamino‐1,2,4‐triazolium perchlorate ( 4 ), respectively. In a second step 4 reacted with potassium dinitramide forming 3,5‐diamino‐1,2,4‐triazolium dinitramide ( 5 ) and low soluble potassium perchlorate. Compounds 2 – 5 were characterized by low temperature single X‐ray diffraction, IR and Raman as well as multinuclear NMR spectroscopy, mass spectrometry and differential scanning calorimetry. The heats of formation of 1 – 5 were calculated by the CBS‐4M method to be 81.1 ( 1 ), 124.7 ( 2 ), –76.1 ( 3 ), –25.2 ( 4 ) and 138.7 ( 5 ) kJ·mol^–1. With these values as well as the X‐ray densities several detonation parameters were calculated using both computer codes EXPLO5.03 and EXPLO5.04. In addition, the sensitivities of 1 – 5 were determined by the BAM drophammer and friction tester as well as a small scale electrical discharge device.     

Thermal behavior of 3,4,5-triamino-1,2,4-triazole dinitramide

The thermal decomposition behavior of 3,4,5-triamino-1,2,4-triazole dinitramide was measured using a C-500 type Calvet microcalorimeter at four different temperatures under atmospheric pressure. The apparent activation energy and pre-exponential factor of the exothermic decomposition reaction are 165.57 kJ mol⁻¹ and 10^18.04 s⁻¹, respectively. The critical temperature of thermal explosion is 431.71 K. The entropy of activation (ΔS ^≠), enthalpy of activation (ΔH ^≠), and free energy of activation (ΔG ^≠) are 97.19 J mol⁻¹ K⁻¹, 161.90 kJ mol⁻¹, and 118.98 kJ mol⁻¹, respectively. The self-accelerating decomposition temperature (T _SADT) is 422.28 K. The specific heat capacity of 3,4,5-triamino-1,2,4-triazole dinitramide was determined with a micro-DSC method and a theoretical calculation method. Specific heat capacity (J g⁻¹ K⁻¹) equation is C _p = 0.252 + 3.131 × 10⁻³  T (283.1 K < T < 353.2 K). The molar heat capacity of 3,4,5-triamino-1,2,4-triazole dinitramide is 264.52 J mol⁻¹ K⁻¹ at 298.15 K. The adiabatic time-to-explosion of 3,4,5-triamino-1,2,4-triazole dinitramide is calculated to be a certain value between 123.36 and 128.56 s.     

Decomposition mechanism of dinitramide onium salts

Thermal decomposition of dinitramide onium salts proceedsvia the dissociative mechanism when pK _a of the base is lower than 5.0 andvia the monomolecular decay of the anion at pK _a>7.0. On going from the melt to the solid state, the reaction mechanism does not change, and the rate decreases by 1–2 orders of magnitude. No anomalous effects inherent in dinitramide metal salts in the solid phase are observed during decomposition of onium salts. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 1951–1953, November, 1997     

Application of dinitramide salts (Review)

Published data on application areas of ammonium and other salts of dinitramide, new components of condensed energetic systems, are discussed. Originally suggested as nearly exclusively oxidants for rocket propellants and explosives, these compounds have significantly expanded their application areas, and this occurred not only in defense, but also in nondefense fields.     

Kinetic Stability and Propellant Performance of Green Energetic Materials

A thorough theoretical investigation of four promising green energetic materials is presented. The kinetic stability of the dinitramide, trinitrogen dioxide, pentazole, and oxopentazole anions has been evaluated in the gas phase and in solution by using high‐level ab initio and DFT calculations. Theoretical UV spectra, solid‐state heats of formation, density, as well as propellant performance for the corresponding ammonium salts are reported. All calculated properties for dinitramide are in excellent agreement with experimental data. The stability of the trinitrogen dioxide anion is deemed sufficient to enable synthesis at low temperature, with a barrier for decomposition of approximately 27.5 kcal mol^?1 in solution. Oxopentazolate is expected to be approximately 1200 times more stable than pentazolate in solution, with a barrier exceeding 30 kcal mol^?1, which should enable handling at room temperature. All compounds are predicted to provide high specific impulses when combined with aluminum fuel and a polymeric binder, and rival or surpass the performance of a corresponding ammonium perchlorate based propellant. The investigated substances are also excellent monopropellant candidates. Further study and attempted synthesis of these materials is merited.