The hydrothermolysis of the water-soluble alkyl azide dimethyl-2-azidoethylamine (2-DAMEZ) was studied at 200-250 degreesC and 275 bar in real time by flow reactor FTIR spectroscopy. The kinetics of 2-DAMEZ decomposition by N-3(-) formation represents a minor channel (8% at 250 degreesC). The main channel is loss of N-2 whose presence was determined by mass spectrometry. The Arrhenius parameters for decomposition by the two routes are E-a = 14.1 kcal/mol and ln(A, s(-1)) = 10.7 for the N-2 channel and E-a = 17.4 kcal/mol and ln(A, s(-1)) = 11.8 for the N-3(-) channel. Because of further reactions the organic products could not be identified, but (CH3)(3)N appears to be a major product. The N-3(-) ion was found to be stable in water at least to 340 degreesC. However, protonation of N-3 to form HN3 was pH dependent. DeltaH values for the reaction were calculated from a van't Hoff plot. It was found that changes in the bulk dielectric constant affect the equilibrium more than do changes in K-w in the 300-340 degreesC range. Ion pairing of NaN3 and LiN3 was also spectrally observed.

An overview is presented of the status of chemical measurements of the condensed phase and the near-field gaseous phase of decomposing energetic materials. Various categories of energetic materials are surveyed first. The experimental and computational approaches for specifying the most important chemical reactions and rates in the condensed and near-surface gaseous phase are discussed along with the use of these chemical data in qualitative combustion models. Emphasis in the presentation is placed on the nitramines HMX and RDX.

The relative roles of the materials of construction of the reactor (stainless steel or titanium) and the effects of Group I cations are discussed in terms of their effect on the rate of decarboxylation of acetic acid derivatives, RCO2H. Past work indicates that the reaction container composition has a very large effect when R is CH3 - A smaller but significant effect is seen when R is electron neutral (i.e., R = H). When R is electron withdrawing the rate depends less on the reactor type than the nature of R. The effect of the counter ion M on the rate of decarboxylation of monovalent malonate salts, HCO2CH2CO2M, is discussed for M=Li+,Na+,K+,Rb+, and Cs+. The rate generally increases with the ionic radius except that the Rb+ salt exhibits the fastest rate. Preliminary explanations are given.

The molecular structures of five furazan compounds in which two amino- or nitro-substituted furazan rings are bridged by ate, azoxy or hydrate groups were determined by single crystal X-ray crystallography. These are diaminoazofurazan, diaminoazoxyfurazan, diminoazoxyfurazan, diaminohydrazofurazan and dinitrohydrazofurazan. The structures are compared to those previously reported on dinitroazofurazan, aminonitroazoxyfurazan and another polymorph of diaminoazoxyfurazan.

Density functional theory (DFT) was used to calculate the heats of formation and infrared active vibrational frequencies of twelve furazan compounds. The absolute values of the heats of formation are unreliable but the trends with systematic variations of the bridge and terminal groups are reasonable. The assignments of the vibrational motions to IR frequencies based on a force field analysis are given to clarify the complex coupling in these molecules. Thermische Zersetzung von Energetischen Materialien 78. Untersuchungen zu Molekülschwingungen und Bildungswärmen von Furazanen mittels DFT DFT (density functional theory) wurde zur Berechnung der Bildungswärmen und infrarotaktiven Schwingungsfrequenzen von zwölf verschiedenen Furazan-Verbindungen eingesetzt. Auch wenn die berechneten Absolutwerte der Bildungswärmen kritisch zu betrachten sind, zeigen sie einen klaren Trend bei systematischer Variation der verbrückenden und terminalen Molekülgruppen auf. Die Zuordnungen der Schwingungsbewegungen zu IR Frequenzen auf der Basis von Kraftfeld-Analysen zeigen die komplexen Kopplungs-verhältnisse in diesen Molekülen auf. Décomposition thermique de matériaux énergétiques 78. Études des vibrations moléculaires et de la chaleur de formation des furazanes par DFT La DFT (density functional theory) a été utilisée pour le calcul des chaleurs de formation et des fréquences de vibration actives dans l'infrarouge de douze composés furazanes différents. Les valeurs absolues des chaleurs de formation ne sont pas fiables, mais les tendances, lorsqu'on fait varier systématiquement les ponts et les groupes terminaux, sont raisonnables. Les affectations des mouvements de vibration aux fréquences IR sur la base d'une analyse de champs de forces montrent les couplages complexes dans ces molécules.

Flash pyrolysis of energetic compounds that are unusually rich in nitrogen can be expected to liberate a large amount of N 2 among other products. In addition H 2 and O 2 can be pyrolysis products from other types of energetic compounds. While many kinetics and mechanistic details have been learned from T-jump/FT-IR (Fourier transform infrared) spectroscopy, the development of the complementary method of T-jump/Raman spectroscopy described herein helps to complete the elemental atom balance of the gaseous products. Differential Raman scattering cross sections were determined for many of the common gases resulting from pyrolysis of energetic compounds. The spontaneous Raman scattering by the products of hydrazinium [3-nitro-4-nitraminofurazan], poly(bis(3,3′-azidomethyl)-oxetane), poly(glycidyl azide) as the mono-ol derivative, and 5-nitriminotetrazole were determined. Provided that at least one of the quantified species is common to both the IR and Raman spectra, the Raman-based data can be combined with the IR data to give a properly balanced gasification reaction.

The temperature dependence of the infrared absorptivity of the asymmetric stretch of CO2 and N2O dissolved in H2O was determined at 300–600 K under 275 atm. These results are essential for using these species as internal calibrants of the rate of many hydrothermal reactions by infrared spectroscopy. The absorptivity (band area) for ν3(CO2) at constant number density increases from 1.58 × 104 cm/mmol at 300 K to 2.68 × 104 cm/mmol at 600 K. The absorptivity of ν3(N2O) is 8.57 × 103 cm/mmol at 300 K and 1.33 × 104 cm/mmol at 525 K. The absorptivity is suppressed in the presence of H2O by a factor of about 5 compared to results for the gas phase. The absorptivity increases, however, with increasing temperature in H2O solution, which is opposite the trend for the gas phase. The Lorentzian line shape in H2O solution provides a global relaxation time of <1 ps, which is more consistent with relaxation by vibrational energy transfer among associated molecules than by collisions or stochastic modulation by the surrounding H2O field.

The kinetics and pathway of hydrothermolysis of 1 m NH(4)SCN to CO(2), NH(3), and H(2)S were determined at 543-573 K and 275 bar by the use of FTIR spectroscopy and a Pt/Ir flow reactor with diamond windows or a 316 stainless steel flow reactor with sapphire windows. The rates of SCN(-) loss and CO(2) formation were the same. The reaction is (pseudo) second-order with E(a) = 113 +/- 11 kg/mol and ln(A, kg/(mol.s)) = 21 +/- 2. DeltaS() = -84 J/(mol.K), which suggests a bimolecular, rate-determining, initial decomposition step for NH(4)SCN. A reaction scheme is proposed in which OCS and a monothiocarbamate species are undetected intermediates. The absence of OCS is explained by the rapid hydrothermolysis rate of OCS to CO(2) and H(2)S which was determined by IR spectroscopy at 393-423 K under 275 bar to be E(a) = 44 +/- 5 kJ/mol and ln(A/s) = 13 +/- 1 for OCS. The resulting rate is about 10(3) times faster than the hydrothermolysis rate of NH(4)SCN at 543 K. The results are compared to the equivalent reaction for NH(4)OCN. NH(4)OCN reacts about 3 x 10(3) times faster than NH(4)SCN at 543 K. The trend in the rates is consistent with the charge distribution and the trend in the bond distances, which resulted from ab initio quantum mechanical calculations at the HF/N311G//HF/N31G level in the OCN(-) and SCN(-) ions and the proposed carbamate and monothiocarbamate intermediates.

The approximate identity and temperature dependence of volatile “minor” products (defined as <4% mole fraction) from thermal decomposition of hexahydro-1,3,5-trinitro-s-triazine, RDX, were determined by heating a film at 800°C/sec under 4 atm Ar. The IR spectra from pyrolysis at specific temperatures in the 265–325°C range were resolved by multivariate regression, which enabled the major products to be removed and the minor products to be uncovered. The gaseous phase contained hexahydro-1-nitroso-3,5-dinitro-s-triazine (MRDX), a triazine modeled as s-triazine (TAZN), C-hydroxyl-N-methylformamide (HMFA), and both RDX vapor (RDXv) and aerosol (RDXs). The behaviors of HONO and HNCO are also discussed because they have mole fractions below 4%. The concentrations of MRDX, HMFA, RDXv, and RDXs decrease with increasing temperature. HONO and TAZN maintain relatively constant concentrations. HMFA and HNCO are oppositely correlated, suggesting that HNCO comes from HMFA. The relation between this work and previous studies of slower decomposition of RDX and on quenched burning of RDX-containing propellants is discussed in an attempt to unify the description of amides and nitrosoamines in the RDX decomposition scheme over a wide range of heating rates.

Diaminoglyoxime was reacted in water at 150–400°C and at 27.5 MPa pressure in metal Ti tubing reactor. Experimental results indicate that, diaminoglyoxime can be converted into NH 3 and CO 2 , either through direct hydrolysis or through pyrolysis and polymerization, and then further hydrolysis. The possible reaction mechanism is nucleophilic addition of water.