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Results of investigations of flame acceleration and deflagration-to-detonation transition in circular smooth tubes performed for several last years at the ITMO University (Minsk, Belarus) are briefly reviewed and systematized. All stages of the flame acceleration process from initiation with a weak source to detonation are demonstrated and described.

To date, compounds having an adamantane moiety have found wide application in the pharmaceutical industry. Despite the fact that most biologically active adamantyl-bearing derivatives contain substituents in the first position of the adamantane molecule, some derivatives with substituents in the second position have also shown valuable pharmacological properties. While 1-adamantanecarboxylic acid is an inexpensive and commercially available reagent, its 2-substituted analogue is substantially less available, and therefore, the development and optimization of approaches to the synthesis of 2-adamantanecarboxylic acid are of great importance. In this work, a three-stage method for the synthesis of 2-adamantanecarboxylic acid has been optimized, based on the Corey-Chaykovsky reaction of 2-adamantanone with trimethylsulphoxonium iodide in the presence of potassium hydroxide, followed by acid-catalyzed opening of the oxirane ring and oxidation of aldehyde 9 to the target carboxylic acid. The total yield of the target product is 70 %.

The dianion generated by the reduction of terephthalonitrile with sodium in liquid ammonia arylates di- and trifluorobenzonitrites replacing the ortho - and para -fluorine atoms, as well as the para -hydrogen atom, with the para -cyanophenyl fragment. The orientation of the interaction, the structure of the resulting fluorinated 4,4'- and 2,4'-dicyanodiphenyls, and reaction productivity are determined by the location and number of fluorine atoms in the starting benzonitrile.

1-Alkoxy-3-imidazolines derived from stable nitroxide radicals, as well as nitroxide radicals themselves, bearing the 2-pyridyl substituent in position 2, under mild conditions undergo acid-catalyzed rearrangement with the fragmentation of the imidazoline ring and the formation of imidazo[1,5-a]pyridine. This rearrangement does not occur in superacid media due to the protective protonation of the nitrogen atom of the pyridyl substituent.

For the analysis of fluorine in difficult-to-burn and complex organofluorine compounds, special additives have been developed to ensure complete decomposition of the substances. Using a spectrophotometric technique based on the formation of а fluoride complex with lanthanum alizarin complexone, various organofluorine compounds have been analyzed with fluorine content of 1.5 to 70 % containing heteroelements in their structures: sulphur, chlorine, bromine, phosphorus, boron, selenium, tellurium in various combinations, as well as metals. The error of determination was established to be not higher than 0.5 abs. %

The effect of leuzea (Rhaponticum carthamoides) and cranberry (Vaccinium oxycoccus) meal extracts composition at a dose of (70 + 500) mg/kg, as well as individual active substances (ecdisten and ursolic acid) in equivalent doses, on the biochemical parameters of physical endurance (lactate, glucose) in the forced swim test on CD-1 male mice is investigated. It has been established that the developed composition exhibits pharmacological effects similar to those of the individual active substances promoting a decrease in the concentration of glucose (in blood) and lactate (in blood and in muscles).

The formation of a complex of magnesium and 4-ethylterpiridyl-(N-tert-butyl-N-(1-diethylphosphone-2,2-dimethylpropyl))-nitroxide alkoxyamine (SG1-tpy) was investigated by means of NMR spectroscopy. The stoichiometry of the complex was determined by constructing the Job’s plot. The homolysis rate constant of the alkoxyamine used was determined by means of EPR spectroscopy, and the activation energy was estimated. Polystyrene was obtained by radical controlled polymerization, and its molecular weight characteristics were studied by gel-permeation chromatography. When magnesium trifluoroacetate is added to the polymer solution, the molecular weight of the polymer increases, which indicates the formation of the complex. Polystyrene was also synthesized using the complex form of the initiator. It is shown that all the obtained polymers are narrowly dispersed, polydispersity is less than 1.5.

Copolymer of 2-(4-acryloylpiperazin-1-yl)methyl)-9H-thioxanthen-9-one and methyl methacrylate was synthesized by radical polymerization. This copolymer has high molecular weight characteristics and is capable of forming long-lived anion radical states of the pendant thioxanthenone groups during electrochemical reduction. Using a combination of electrochemical and optical methods, it has been shown that the electronic states of the pendant groups are located within the band gap of methyl methacrylate and may promote the Frenkel mechanism of conductivity in dielectric thin films used in resistive memory devices.

Mass spectrometric characteristics of N-alkyl-4-nitro-1,2,3-triazoles were investigated using a gas chromatograph with a quadrupole mass spectrometric detector in the mode of electron ionization (70 eV). The stability of the molecular ion was studied depending on the position, structure and nature of the alkyl substituent at the endocyclic nitrogen atoms of nitrotriazole heterocycle. N2-alkyl-4-nitro-1,2,3-triazoles were found to have the highest stability and molecular ion intensity, independently of the alkyl substituent in the structure of the compound. The pathways of molecular ion fragmentation are proposed for the compounds under consideration, and characteristic ions are identified. Molecular ion fragmentation in N-alkyl-4-nitro-1,2,3-triazoles was discovered to start with the elimination of the exocyclic NO₂ group, followed by detachment of the respective alkyl substituent and generation of the cation radical of 1,2,3-triazole. Fragmentation of non-substituted cation radical of 1,2,3-triazole proceeds through characteristic detachment of N atom or neutral molecules N₂ and HCN. In turn, the ionic decay of bulky alkyl substituents (cyclohexyl and benzyl radicals) leads to a group of characteristic ions with high relative intensity. In general, the findings demonstrate that mass spectrometry can be efficiently used for robust identification of structural isomerism ( N1-, N2- and N3-isomers) of alkyl-4-nitro-1,2,3-triazoles and the products of their decomposition.

Vitrinite concentrates of coal at different stages of metamorphism are studied by means of scanning electron microscopy and X-ray diffraction analysis. The results show that the cleaves and fractures on the surface of maceral particles have a structure characteristic of vitreous amorphous bodies for the whole metamosphism series. An increase in metamorphism degree is accompanied by an increase in the electrical conductivity of vitrinite particles and a decrease in the reflectivity with respect to electrons due to a decrease in the content of oxygen atoms. It is shown by means of X-ray diffraction that vitrinites have a turbostratic carbon structure, formed by polyarene layers with the interlayer spacing (d₀₀₂) decreasing from 3.64 to 3.50 Å with an increase in metamorphism stage, at the same time an increase in the dimensions of structured vitrinite fragments - height (L_c) andd width (L_a) of arene layer packets - is observed. A linear dependence is revealed between d₀₀₂ and vitrinite reflectance.