Vol 65, No 10 (2016)

The review presents original methodological approaches and summarizes the results of research into the assessment of relationships between the structure of energetic organic compounds and their main physicochemical properties. A large number of experimental values of these parameters were statistically analyzed, and a database of the properties of explosives and rocket propellant ingredients was created. Based on the analysis and integration of these data, approaches were developed to evaluate the fundamental properties of energetic compounds of different chemical classes, such as the enthalpy of formation, the molecular crystal density, and the sensitivity to mechanical impacts. The explosive and ballistic characteristics were calculated. The comprehensive assessment was made of the possible applications of new substances and those poorly characterized by experimental methods.

The quantum chemical modeling and topological analysis of transition states of the concerted molecular decomposition of haloalkanes and alcohols with the elimination of HHal and HOH were performed for the ten compounds. The possibility of formation of two types of transition states was mentioned, and their electronic structures were studied. The influence of the alkyl substituent at the C atoms on the binding energy and the nature of the transition state was shown. The decomposition activation energies were calculated using the method of density functional theory (DFT/B3LYP/6-311++G**) and the intersecting parabolas method. The calculated results were compared, and their agreement was shown.

The analysis of reported data on the interaction of ozone with alkaline solutions of Pu^VI leads to the conclusion that the process of ozonation involves reactions O₃ + OH^– → HO₂^- + O₂, O₃ + + HO₂^- + OH^– → O₃^- + O₂^- + H₂O and O₃ + O₂^- → O₃^- + O₂. The O₃^- radical ion oxidizes Pu^VI, the HO₂^- and O₂^- anions reduce Pu^VII and Pu^VI and react with O₃^-. Using persulfate instead of O₃ in aerated solution at 80—95 °C results in thermal decomposition of the S₂O₈^2- anion into radical ions of SO₄^-, oxidizing OH^– to the O^– ion, which in reaction with O₂ forms O₃^-. The oxidation of PuVI proceeds via the formation of an activated complex with O₃^-. where charge transfer occurs with the simultaneous elimination of two H⁺ ions. A similar mechanism is operating in reactions of Pu^VI with BrO^–, Fe(CN)₆^3–, Am^VI, and Am^VII. Upon the γ-radiolysis of alkaline solutions of Pu^VI saturated with N₂O or containing S₂O₈^2–, e_aq^– is converted into O^– and then into O₃^-; F₂ and XeF₂ in alkaline solutions are decomposed with the formation of H₂O₂, which prevents producing Pu^VII.

The one-dimensional problem was studied. A constant-cross-section tube was filled with two gaseous components, A and B, at a fixed initial temperature. The reactants were diluted with the lightest inert gas E (He). The ignition of the reactants and subsequent rapid heating of a closed end of the tube to a certain temperature was followed by the initiation of a reversible reaction A + B ⇄ 2 C involving molecules with considerably different weights (an analog of the only important reaction O + O₃ ⇄ 2 O₂ under the simulation conditions), with the energy thresholds for the forward and reverse reactions. The latter led to realistic values of the rate constant and the heat release for the reaction. All calculations were carried out by the direct simulation Monte Carlo method with variable weight factors on a multiprocessor computer. Molecules were treated as hard spheres with no internal degrees of freedom. It was found that the reaction rate at the leading egde of the detonation wave front is much higher than the equilibrium reaction rate behind the front.

Physicochemical characteristics of the functional electrode nanocomposites based on porous silicon with platinum nanoparticles were investigated with the use of electron microscopy, X-ray diffraction, and cyclic voltammetry. It is established that a decrease in the platinum nanoparticle size leads to an increase in catalytic activity of nanocomposites in the reactions of electrocatalytic oxygen reduction and hydrogen oxidation.

Self-assembly of monostyryl dye of benzothiazole series with symmetric and asymmetric bisstyryl dyes based on dibenzo-18-crown-6 ether has been studied by optical and NMR spectroscopies. The photoinduced energy transfer between monoand bisstyryl dyes in supramolecular assembly has been analyzed. The cascade energy transfer in the supramolecular complex of monostyryl dye with asymmetric bisstyryl dye has been suggested.

The possibility of preparation of calcium molybdate directly by roasting of commercial molybdenite concentrate in the filtration combustion mode in the presence of calcium compounds was investigated. The optimal process conditions and the conversion of molybdenum sulfide to calcium molybdate were determined.

The influence of pressure on the oxidative cracking of light alkanes C₂—C₄ was investigated. An elevated pressure reduces the temperature of oxycracking of light alkanes but with further increase in pressure the effect is reduced. The applied pressure decreases the temperature of the total conversion of oxygen while the maximum conversion of alkanes is not influenced. The pressure above atmospheric promotes oxidative cracking reactions but weakly affects thermal processes. At deep conversion of light alkanes, the selectivity towards main products is nearly invariable at the utilized pressures.

The quantitative data on the influence of molecular organization of CH₂Cl₂ solutions of diazidopropanol and its non-azide analog (isopropanol) and the concentrations of the alcohols and catalyst (dibutyltin dilaurinate) on the kinetics of urethane formation via the reaction with 1,6-hexamethylene diisocyanate were obtained. The series of reactivity were composed for various associates of hydroxyl groups of these alcohols in solutions in the catalytic and non-catalytic reactions.

1,4-Dichloro-3a,6a-diaza-1,4-diphosphapentalene reacts with sodium acetylacetonate to form an adduct of diacylcarbene with trivalent dicoordinated phosphorus. In solution this adduct dimerizes according to the head-to-head type. The phosphorus atoms undergo transformation from the hypervalent state (in the adduct), in which the lone electron pair on the phosphorus atom is not involved in the formation of additional bonds with this phosphorus(III) atom, to the pentavalent pentacoordinated and trivalent tricoordinated state (in the dimer).

Thermolysis of polytriarylcarbinol (PTAC-Li) (lithium salt of polydiphenylenesulfophthalide (PDSP)) was studied in the temperature range from 100 to 500 °С by thermogravimetric analysis (TG) and IR and electronic spectroscopy to check the available data on the higher thermal stability of PDSP salts over the initial polymer. The mass losses detected by the TG method in the polymer salt at 80—150 and 240—350 °С are mainly caused by the desorption of weakly and strongly bound water. According to the calculations in the B3LYP/6-311+G(d,p) approximation, the С—ОН and C—SO₃^-Li⁺ bonds are weakest in the carbinol model for PTAC-Li (D(C—O) ~ D(C—S) ~ 72 kcal mol^–1). The thermolysis of PDSP is accompanied by SO₂ evolution, whereas hydroxy and sulfo groups detached from PTAC-Li macromolecules remain in the thermolyzate. Phenol fragments and an inorganic phase, the final form of which is lithium sulfate, are formed in this process. An analysis of the IR and UV spectra of the thermolyzates of PTAC-Li and PDSP confirmed that fluorenyl fragments are predominantly formed upon the thermolysis of these polymers. The data obtained do not confirm a higher stability of PTAC-Li compared to that of PDSP.

The absorption spectrum of iminium ylide (λ_max = 450 nm) has been registered under the conditions of acid-catalyzed consumption of styrene epoxide under the influence of p-toluenesulfonic acid (MeCN, Bu^tOH (90 vol.%) + chlorobenzene (10 vol.%), 343 K) in the presence of pyridine. The spectrum coincides with the spectrum of the ylide product of the interaction of pyridine with phenylcarbene of phenylmethylene formed in the conventional flash-photolytic preparation of carbene from diazo derivative. The result confirms the earlier assumption on the formation of the particles of carbene nature reacting with oxygen in the epoxy-acid system. In the absence of O₂ these particles destruct introduced hydroperoxides. The spectra of corresponding carbonyl oxide (λ_max ≈ 408, 400 nm) in the presence and absence of pyridine were recorded in acetonitrile.

A synthetic procedure towards 4,6-diisopropyl-3-nitro-1,2-benzoquinone was elaborated. Based on this benzoquinone, a series of novel 5,7-diisopropyl-2-(quinolin-2-yl)-1,3-tropolones and 5,7diisopropyl-2-(quinolin-2-yl)-4-nitro-1,3-tropolones were derived. Molecular structure of 2-(4-chloro-8-methylquinolin-2-yl)-5,7-diisopropyl-1,3-tropolone was established by X-ray diffraction analysis. Energetic and structural characteristics of isomeric 5,7-diisopropyl-2-(quinolin-2yl)-1,3-tropolones and 5,7-diisopropyl-2-(quinolin-2-yl)-4-nitro-1,3-tropolones in the gas phase and in the polar solvent were calculated by quantum chemistry method (PBE0/6-311+G(d,p)).

Cyclocondensation of 1-hydroxyketones with thiosemicarbazide resulted in thiadiazines. Nitrate ester of 1-hydroxyketone reacted under similar conditions to give the corresponding thiosemicarbazone. In the case of bromoacetyl-substituted nitrate ester of 1-hydroxyketone, condensation proceeded via intramolecular reaction between the thiol and bromomethyl groups.

Some features of the complexation of [Rh₂(OAc)₄•2H₂O] with calix[4]resorcinarenes functionalized by aminoalkyl groups in the upper or lower rims in EtOH and Me₂CO are considered. The properties of complexes were studied by IR, UV—Vis, Raman, ESR, ¹H NMR spectroscopies, simultaneous thermal analysis, and conductommetry. It is shown that the way of coordination of calixresorcinarene matrix to the central atom, either through the donor nitrogen atoms of outer aminoalkyl groups or through oxygen atoms of resorcinarene groups, is determined by conformation and configuration capabilities of the ligands and the nature of the solvent.

The dependence of the combustion parameters of cellulose nitrate (nitrocellulose, NC) mixtures with magnesium oxide on the content of the energetic component was studied to reveal peculiarities of the combustion of NC in ballasted systems. It is experimentally shown that the combustion occurs in the flameless low-temperature region at the NC content in a mixture with magnesium oxide lower than 60%, and the reactive smoke reaction products can be ignited by a secondary thermal igniter heated to the temperature higher than 770 K. For the NC content in the initial mixture higher than 60%, a critical increase in the combustion temperature and velocity is observed due to the ignition of the reactive smoke products of NC decomposition inside the sample. The combustion of NC in the flame and flameless regimes is characterized by an intermediate isothermal stage at the temperature about 440 K corresponding to the temperature of onset of the fast NC decomposition. Thus, ballasting of a power material with an inert filler makes it possible to reveal and characterize the spatial and time stage character of its thermal decomposition under the combustion conditions.

The influence of an organic NO donor belonging to non-steroidal anti-inflammatory drugs (NSAIDs) — NO-indomethacin (NO-Ind) on the antitumor effect of cyclophosphamide (CP) and its compositions with asparagyl hydroxamic acid (AHA) were studied, along with the influence on the activity of cytochrome P-450. Compared to a previously studied NSAID — diclofenac hydroxamic acid nitrate — NO-Ind exhibited lower enhancement of CP activity even when hydroxamic acid was added to the drug composition. EPR spectroscopy was used to evaluate the changes in activity of P-450 under the action of modified NSAIDs. The studies demonstrated partial inhibition of cytochrome P-450, the inhibition time is being greater for the first NSAID than for NO-Ind. The duration of P-450 inhibition under the action of different NO donors influences activity of CP.

This review presents data analysis on the impurities in cyclohexanone: pathways of their formation and the influence on the qualty of commercial caprolactam. The existing purification methods are described and their advantages and drawbacks are considered. Novel, increased throughput methods for alkaline hydrolysis of esters in the process of cyclohexanone production are proposed by the authors, based on their expertise.