The kinetics of the thermal decomposition of 1,1-diamino-2,2-dinitroethylene (FOX-7) in the solid state is investigated by the manometric and calorimetric methods. The conditions are found under which the solid-phase reaction and the accompanying fast side processes of substance sublimation and vapor decomposition are separated in time, and the contribution of secondary reactions to the initial rate of solid-phase decomposition is small. The rate constant of the noncatalytic stage of decomposition of the substance in the solid phase is determined under these conditions.

The decomposition rate of 1,1-diamino-2,2-dinitroethylene (FOX-7) at 200°C in a wide range of changes in the conditions of the experiment and methods of sample preparation is measured. The nature of the first stage of decomposition is established and the reason the reaction stopped at this stage is found.

The standard enthalpies of combustion and formation of 7H-tris([1,2,5]oxadiazolo) [3,4-b:3′,4′-d:3″,4″-f]azepine, its bimolecular crystal with the γ-polymorph of CL-20, and the γ-polymorph of CL-20 have been experimentally determined. The standard enthalpies of formation of the bimolecular crystal and an equimolecular mechanical mixture of γ-CL-20 with azepine differ by less than 12.8 kJ/mol. This small difference is validated by quantum chemical calculations. It has been experimentally found that the presence of azepine in the bimolecular crystal inhibits the thermal decomposition of γ-CL-20 and increases the thermal stability of γ-CL-20 in the bimolecular crystal as compared to original γ-CL-20.

New bimolecular crystals (BMCs) of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) with tris[1,2,5]oxadiazolo[3,4-b:3´,4´-d:3″,4″-f]azepine-7-amine (AZ2) were synthesized. Four different crystal structures — two polymorphic modifications with the CL-20: AZ2 ratio of 1: 1 (BMCs 1 and 2) and two polymorphic modifications with the ratio of 1: 2 (BMCs 3 and 4) — were obtained depending on the crystallization conditions. These crystals were studied by X-ray diffraction. The results of quantum chemical calculations indicate that the new η-conformation found in crystal 1 is not a stable conformer of CL-20 and its existence is attributed to the crystal packing effects in structure 1.

The crystal structure of the bimolecular crystal of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and methoxy- NNO -azoxymethane (МАМ) (1:2) is studied. The CL-20 molecules adopt a ζ-conformation. The crystal structure is formed by layers of CL-20 and МАМ molecules, between which there are shortened NO δ– ⋯N δ+ O contacts of the neighboring CL-20 and МАМ molecules.

A novel bimolecular crystal (BMC) of CL-20 and N,N'-dimethyl-N,N'-dinitrooxamide (MNO) has been prepared. Molecular and crystal structures have been determined. Thermal stability has been studied with DSC technique.

The impact sensitivity of the energy systems based on nanoporous silicon, obtained by electrochemical etching of monocrystalline silicon wafers in an HF-containing electrolyte, and calcium perchlorate was studied using a modified Weller—Ventselberg technique (estimation of the impact sensitivity of initiating explosives). The impact sensitivity of these systems is shown to be determined by both the presence of hydrogen, which is stored on the porous silicon surface during the preparation of the latter, and also the influence of other factors, including the specific surface of porous silicon. The composition, amount of the generated gas, and gas evolution rate during nonisothermal and isothermal calcination of porous silicon in a temperature range of 60—120 °С were determined using methods of thermal gravimetry (TG), measurement of the gas volume, and mass spectrometry. The generated gas almost completely consists of hydrogen, and its content in the studied samples of porous silicon achieved ~3.8 wt.%. The calculated activation energy of the hydrogen evolution process in vacuo was 103.7±3.3 kJ mol–1. The dependences of the impact sensitivity of the energy composition based on porous silicon and heat of combustion of porous silicon on oxygen on the hydrogen content were established. The impact sensitivity of the energy system decreases with a decrease in the hydrogen content in porous silicon and its specific surface.

Решающим фактором, обеспечивающим высокую величину удельного импульса (Isp) для заданного предела по температуре горения, является содержание в композиции активного водорода. Современные высокоэнтальпийные энергоемкие компоненты, несущие окислительные функции, содержат очень мало водорода, т.е. создать композицию с высоким содержанием водорода (хотя бы 3—4 %) практически невозможно. Тем более, что в композиции все взаимосвязано и увеличение количества связующего приведет к недостатку активного кислорода для окисления всего углерода. В свете сказанного одним из недостатков самого перспективного энергоемкого компонента — 2,4,6,8,10,12-гексанитро-2,4,6,8,10,12-гексаазотетрацикло[5.5.0.05,9.03,11]-додекана — СL-20 является более низкий процент атомарного водорода в его структуре по сравнению с широко применяемым октогеном. это приводит к снижению эффективности составов при замене последнего на СL-20, особенно в области смесевых твердых ракетных топлив, ограничивая сферу его применения.

3,4-Bis(4-aminofurazan-3-yl)furazan was used to obtain a new energetic terfurazan derivative, namely, bis(4″-nitro[3,3’:4’,3″]terfurazan-4-yl)diazene, the sensitivity of which to mechainical impact was found to be close to that of HMX. The new compound was characterized by NMR spectroscopy, mass spectroscopy, IR spectroscopy, X-ray crystallography, and elemental analysis.

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.

При температурах 160–280°C изучен распад изоксазолинового кольца, образующегося при присоединении этилена к метил- и этилзамещенным бензонитрилоксидам. Реакция заключается в расщеплении изоксазолинового цикла на ацетальдегид и соответствующий ароматический нитрил. Скорость ее в расплаве и в инертных растворителях типа хлорбензола слабо зависит от строения ароматического заместителя, кинетические параметры имеют низкие значения: Е = (104 ± 8) кДж/моль и lg(А, c-1) = 7.2 ± 0.8. Только в том случае, когда бензольное кольцо содержит три этильных заместителя, разложение в расплаве идет быстрее, чем в растворе. Скорость циклораспада уменьшается при увеличении вязкости среды и увеличивается в растворителях, имеющих пониженную прочность связи C–H. Для соединений, полностью дейтерированных в изоксазолиновое кольцо, наблюдается обратный кинетический дейтериевый изотопный эффект. Полученные результаты объяснены в рамках бирадикального механизма раскрытия изоксазолинового цикла, включающего эффективную рекомбинацию бирадикала и его гибель в результате синхронной перегруппировки с выбросом ацетальдегида.

New bimolecular crystals of 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) with 2,4-dinitro-2,4-diazapentane (DNP) and 2,4-dinitro-2,4-diazaheptane (DNG) were obtained in a ratio of 2 : 1 and 1 : 1, respectively. Their X-ray diffraction analyses were carried out. The thermal stability, detonation characteristics, and sensitivity to friction of bimolecular crystal of CL-20 with DNP (CLD) were studied. The detonation characteristics of bimolecular crystal CLD are comparable with the properties of the known bimolecular crystal CL-20—HMX (2 : 1).

The X-ray crystallographic analysis of 1,7-difluoro-1,1,3,5,7,7-hexanitro-3,5-diazaheptane has been carried out. We have also determined its sensitivity to mechanical actions and a set of calculated and experimental data on explosion characteristics.

The decomposition of the isoxazole ring at 160–280°C formed by the addition of ethylene to methyland ethyl–substituted benzonitrile oxides is studied. The reaction consists in the cleavage of the isoxazole ring into acetaldehyde and the corresponding aromatic nitrile. Its rate in the melt and in inert solvents, such as chlorobenzene, only weakly depends on the structure of the aromatic substituent, with the kinetic parameters having low values: E = (104 ± 8) kJ/mol and log( A , s –1 ) = 7.2 ± 0.8. Only if the benzene ring has three ethyl substituents, the decomposition of the compound in the melt proceeds faster than in solution. The rate of the decomposition of the ring decreases with increasing viscosity of the medium, being higher in solvents with a lower strength of the C–H bond. For compounds with the fully deuterated isoxazole ring, the inverse kinetic H/D isotope effect is observed. The results are explained in terms of the biradical mechanism of the opening of the isoxazole ring that involves an effective recombination of the biradical and its loss through a synchronous rearrangement with acetaldehyde release.

The crystal structure of the CL-20 solvate with ɛ-caprolactam in the 1:6 ratio is obtained and studied.