M.I. Epov1, N.N. Mikhailov2,3,4, O.E. Aksyutin5, V.N. Sokotushchenko2, O.M. Ermilov2,6 1Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia 2Gubkin Russian State University of Oil and Gas, Moscow, Russia 3Oil and Gas Research Institute, Moscow, Russia 4Lomonosov Moscow State University, Moscow, Russia 5PAO Gazprom, Saint Petersburg, Russia 6OOO Gazprom Dobycha Nadym, Nadym, Russia
Keywords: Skin factor, Hawkins model, three-zone model, permeability, radial permeability variation, near-wellbore region, linear permeability variation
This study extends the classical skin-factor concept originally proposed by M.F. Hawkins. A fundamental limitation of the Hawkins model is identified: the permeability of the drilling-fluid filtrate invasion zone is assumed to remain constant ( k skin = const). Based on an analysis of recent experimental evidence, an integrated skin-factor model is developed in which the permeability ( k ) of the near-wellbore region is represented as a function of both the radial distance ( r ) from the wellbore wall and pressure ( p ): k = k ( r , p ). The proposed model comprises three characteristic invasion zones, each governed by a distinct mechanism of permeability variation. Comparative simulations reveal substantial differences between the classical Hawkins model and the proposed three-zone model, k = k ( r ), as well as the integrated model, k = k ( r , p ). Assuming a linear radial variation in permeability, comparative relationships are obtained between the normalized production rate and the skin factor, as well as between the skin factor, the production rate, and pressure drawdown. The classical Hawkins model is shown to overestimate the production rate by an average of 15-25%, with deviations increasing to 40-50% in the zone of maximum invasion. The results are of fundamental importance for the theory of flow through porous media and have practical significance for oilfield development planning by providing a basis for selecting well stimulation methods according to the characteristics of individual invasion zones.
D.A. Nosov1, D.K. Dronov2, Yu.G. Turbin2, I.S. Sizikov1 1Institute of Automation and Electrometry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia 2Arctic and Antarctic Research Institute, St. Petersburg, Russia
Keywords: Absolute gravimeter, ice-resistant platform (IRP), gravity acceleration, relative gravimeter, gyrostabilized platform, North Pole-42 expedition
We present our first experimental work with the GABL-PM absolute ballistic laser gravimeter on a pier, in ports and on board of an ice-resistant platform (IRP) in the expedition North Pole-42 (NP-42). During the tests, we parametrically adjusted the gravimeter to adapt it for the operation on the IRP without using a gyrostabilized platform. The results of the GABL-PM measurements on the pier in St. Petersburg are shown; they are required as reference to test the gravimeter on the vessel, as well as to tie variations in gravity acceleration measured on board of the IRP using the Chekan-AM relative gravimeter to absolute values. The estimation of the root-mean-square (RMS) error of the GAB-PM measurement on board of the IRP at various pitching parameters in the ports of St. Petersburg and Murmansk, as well as in the early days of the start of the drift of the North Pole-42 expedition, is given. Based on the measurement results, we conclude that a gravimeter without a gyrostabilized platform with reduced accuracy values, on average up to 0.60 mGal, can be used for measurements after freezing the vessel in ice and when all the requirements of a specially developed manual are met.
S.Yu. Davydenko1,2, M.S. Sudakova1,2, M.R. Sadurtdinov1, A.G. Skvortsov1, A.M. Tsarev1, G.V. Malkova1 1 Earth Cryosphere Institute, Tyumen Scientific Centre, Siberian Branch of the Russian Academy of Sciences, Tyumen, Russia
2Lomonosov Moscow State University, Faculty of Geology, Moscow, Russia
Keywords: cryolithozone, permafrost, ground penetrating radar, ground penetrating radar sounding, seismic exploration, electrical resistivity tomography.
The article presents the results of applying an integration of geophysical methods (ground-penetrating radar in profiling and sounding modes, seismic reflection survey using SH-waves, electrical resistivity tomography, and thermometry) to determine the geocryological section at the Kumzha research station in the Pechora River delta (Nenets Autonomous Okrug). Fieldwork was carried out in August 2023 and from late July to early August 2024. The application of this integrated approach made it possible to determine the position of the table and base of the permafrost at depths of 5–8 m and 20–22 m, respectively; establish the thickness of the frozen layer as 11–16 m; identify the boundary between frozen sand and clays within the permafrost at a depth of 10–12 m; and determine the location of the island permafrost. Transverse SH-wave velocities were determined as follows: 200–300 m/s in the seasonally thawed layer (active layer), 1300 m/s in the frozen sand, and 820 m/s in the lower frozen clay layer. The electrical resistivity values are: 300–1500 Ohm·m for the seasonally thawed layer (sand), >10,000 Ohm·m for frozen sand, 500–2000 Ohm·m for frozen loams, and 5–100 Ohm·m for thawed clays. The electromagnetic wave velocity in the aeration zone (dry sands) was 10–11 cm/ns, decreasing to 6 cm/ns in fully saturated sands and increasing to 11 cm/ns in frozen sands. The integration of these methods ensured mutual verification of the geological boundaries (taking into account drilling and thermometry data) and enabled the construction of a reliable petrophysical–geological model of the geocryological section.
V.D. Korchuganov1, A.A. Duchkov1, 2, A.A. Kozyaev3, A.V. Sadchikova3, E.A. Pobezhimov1, A.A. Lisin1,2, M.S. Golubeva1 1Novosibirsk State University, Novosibirsk, Russia 2Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia 3Branch of RN-GIR LLC, Krasnoyarsk, Russia
Keywords: 3D seismic exploration, seismic inversion, multi-objective optimization, parameter tuning, Pareto front, NSGA-II
Seismic inversion is a widely used method of quantitative interpretation in seismic exploration aimed at recovering the elastic properties of the subsurface from seismic data. Subjectivity in selecting computational parameters, including regularization weights and the wavelet, remains a significant problem in practical inversion. Existing approaches to their determination, such as L-curve analysis and related methods, generally involve repeatedly solving the inverse problem for parameter values on a regular grid, followed by an analysis of the stability of the resulting solutions. This strategy effectively reduces to a search through the parameter space and is characterized by low computational efficiency. In addition, the L-curve-based methods considered here are primarily focused on minimizing the misfit between modeled and observed seismic data, whereas the consistency of the inverted model with well-log data is not used as a separate criterion. In this study, we propose a parameter selection approach based on multi-objective optimization. A vector-valued objective function is constructed, consisting of criteria that quantify consistency with both well-log data and seismic data. The optimal solution is selected from the set of Pareto-optimal models as a compromise between these criteria. The method was tested on data from a field in the East Siberian petroleum province. Quantitative evaluation of the inversion results showed an improvement in the selected metrics compared with an L-curve-based scheme for selecting the regularization parameter in the experimental setting considered.
This paper presents the results of a geochemical study of carbonatite breccias from the Sallanlatva massif (Devonian Kola Alkaline Province). It has been established that, despite the three-stage history of deformation, only the second and third stages of the associated fluid influx significantly influenced the petrochemical characteristics of the rocks. The second stage involved the contribution of Ca, Mg, Na, Si, Al, P, S, high-field strength elements (excluding Th), and heavy rare-earth elements (REE). The third stage featured the enrichment in Ba, Sr, S, light REE, and Th. The results revealed no significant fluid-mediated transport of Fe and Mn: the main source of these elements was the siderite in the breccia clasts, and their redistribution occurred via dissolution–reprecipitation reactions. Our research has established that the redistribution of REE was controlled by two processes occurring at different stages: the enrichment in heavy REE is associated with hydrothermal apatite mineralization (the second stage), whereas the concentration of light REE is related to the superimposed ancylite mineralization (the third stage). A consistent geochemical trend for breccias and carbonatites in the Ba–Sr–REE coordinate system indicates that the enrichment processes affecting the massif to a depth of the first few hundred meters were of a common pattern. The crystallization of the main ore phase—ancylite—occurred at temperatures of ~250–300 °C, and the rate of its precipitation decreased upon cooling of the system and the depletion of rare earth elements, giving way to the precipitation of strontianite and baryte. The joint transfer of Ba and S was facilitated by the reducing properties of the fluid, whereas the extensive deposition of baryte and pyrite was driven by the disproportionation of dissolved sulfur compounds (S⁴⁺) during cooling. The proposed model of fluid system evolution, involving deep fractionation of the alkaline-carbonate melt, the generation of phosphorus-enriched residual fluid, and the subsequent vertical transport of Ba, Sr, and light REE by late aqueous carbonic‑sulfurous solutions, explains the rare-metal metallogenic specialization not only of the Sallanlatva massif but also of other carbonatite massifs in the Kola Alkaline Province.
M.Y. Shumskayte1, K.V. Dolzhenko2, T.A. Yanushenko1, N.A. Golikov1, D.A. Markushin2, A.D. Zakharov2 1Trofimuk Institute of petroleum geology and geophysics SB RAS, Novosibirsk, Russia
2Fianumlab LLC, Moscow, Russia
Keywords: Spin-spin relaxation time, frequency characteristics, pore size distribution, terrigenous rocks, nuclear magnetic resonance
The influence of the operating frequency of the laboratory NMR relaxometry method (2, 12, and 22 MHz) on the accuracy of determining the pore size distribution in terrigenous rocks ranging in size from medium-grained sandstone to silt-argillite is demonstrated. Measurements at 12 and 22 MHz are found to enable the detection of pore throats with small radii, which are characterized by a shift in the spin-spin relaxation time spectra toward shorter times. The high-frequency measurement data are in good agreement with the results of the semipermeable membrane method. A frequency of 2 MHz is shown to systematically overestimate the proportion of large pores, especially in low-permeability samples, which constitute half of the studied collection. The obtained results emphasize the importance of choosing the operating frequency for analyzing rock porosity and permeability using NMR relaxometry, which is particularly important for the application of such data in digitalization and hydrodynamic modeling.
Настоящий номер журнала посвящен памяти академика Валентина Афанасьевича Коптюга (09.06.1931 - 10.01.1997) - выдающегося ученого-химика и организатора науки, вице-президента РАН, председателя Сибирского отделения РАН, директора Новосибирского института органической химии, основателя журнала “Химия в интересах устойчивого развития / Chemistry for Sustainable Development“.
E. K. KARPOVA1, N. V. ADONYEVA1, O. I. YAROVAYA1,2, O. A. LUZINA2, V. V. ORESHKO1,2, K. S. KOVALEVA1,2, S. N. SHARMANKINA1, N. E. GRUNTENKO1 1Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia 2Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
Keywords: insecticides, usnic acid, terpenoids, bornyl acetate, Drosophila melanogaster
A simple and effective testing system for potential insecticides using the fruit fly Drosophila melanogaster is proposed. This insect species is widely used in genetic, toxicological and pharmacological studies due to the ease of its maintenance and the similarity of its fundamental biochemical pathways to other insects. The relevance of the study stems from the need to standardise and automate the process of primary selection of insecticides. The use of Drosophila melanogaster allows for rapid evaluation of the acute and chronic toxicity of compounds, their impact on reproductive function and behaviour, and provides a comprehensive overview of the potential drug impact. The efficiency of the developed method based on using fruit flies to evaluate the insecticidal activity has been demonstrated for a series of compounds including bornyl acetate, for which insecticidal activity has been shown previously, other synthetic derivatives of borneol, as well as semi-synthetic derivatives of usnic acids. The proposed method is simple, inexpensive, and can be easily scaled up for mass screening of compounds with potential insecticidal activity at the early stages of their development.
V. N. KOVTONYUK, Z. CONG, T. V. RYBALOVA
Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
Keywords: octafluorotoluene, resorcinol, ethyl-3, 5-dihydroxybenzoate, fluorinated diaryloxybenzenes, tetraoxacalixarenes
Developing the approach of methods for the synthesis of fluorinated tetraoxacalixarenes, the interaction of octafluorotoluene with resorcinol and ethyl-3,5-dihydroxybenzoate was studied. The possibility of synthesising tetraoxacalixarenes with a different (syn-, anti-) arrangement of the trifluoromethyl group on the outer rim of the macrocycle is shown.
V. A. KONOREV, A. M. AGAFONTSEV, E. V. VASILIEV, V. V. SHELKOVNIKOV
Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
Keywords: photoacid generators, 2-nitrothiophene, vicarious nucleophilic substitution, arylacetic acid nitriles
For developing a convenient method to synthesise 2-(aryl)-2-((hydroxyimino)thiophene-3(2H)-ylidene)-acetonitriles, which are the key intermediates in the synthesis of non-ionic photoacid generators, the conditions for the condensation of 2-nitrothiophene with the nitriles of arylacetic acids have been optimised. It has been shown that this process is most favourable with the use of sodium methoxide in tetrahydrofuran with small additions of methanol. Under these conditions, benzyl cyanides react to form 2-(aryl)-2-((hydroxyimino)thiophene-3(2H)-ylidene)-acetonitriles in the yields of 45-76 %.
T. P. KUKINA1, I. A. ELSHIN2 1Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia 2Novosibirsk State University, Novosibirsk, Russia
Keywords: Populus nigra L, butyrospermol, hop-20(21)-en-3β-ol, epoxidation, azide-alkyne cycloaddition
Epoxidation reactions at the double bond in the aliphatic and cyclic moieties of triterpenoid and sterol molecules, followed by epoxide ring opening using sodium azide, and azide-alkyne cycloaddition reactions catalysed by copper salts offer a wide range of opportunities for the synthesis of new heterocyclic compounds. The synthetically understudied triterpene alcohols - butyrospermol 1 (the major component poplar bark triterpenols) and hop-20(21)-en-3β-ol 8 (a minor component, an isomer of moretenol) differing by double bond localisation in position 20,21 of the E ring were chosen as the starting substrates. Both compounds were isolated from black poplar (Populus nigra L.) bark, a large-scale product of the biomass processing of the Populus genus plants, which are among the main forest-forming and ornamental woody plants. The epoxides of butyrospermol at the double bonds in the aliphatic and cyclic parts of the molecule and the epoxides of hop-20(21)-en-3β-ol acetate at the E ring were synthesised for the first time. Azidoalcohols and 1,2,3-triazoles were obtained for the first time using butyrospermol acetate. Isomeric epoxy diols, formed by hydrolysis of the epoxide at the 24,25 double bond, were detected as byproducts. All starting and synthesised compounds were characterised using 13C and 1H NMR spectroscopy.
K. S. MARENIN, A. V. TKACHEV
Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
Keywords: terpenes, oxime ethers, aminophosphonates, Kabachnik-Fields reaction, Pudovik reaction, stereoselectivity
It has been shown that O-methyl esters of α-aminooximes of the pinane and karan series can be converted into new chiral α-aminophosphonates by the Kabachnik-Fields and Pudovik reactions with dimethylphosphite and a number of aromatic aldehydes, with preparative yields of up to 80 %. The products are formed as a pair of diastereomers, the ratio of which depends on the synthesis conditions.
A. A. NEFEDOV1,2, P. A. BARSUKOV1,3, A. E. OSECHKOVA1,2, E. A. KHOKHRINA1, O. A. RUSALIMOVA3, YU. S. SOTNIKOVA1,2, A. S. KIL’MET’EV1,2, A. V. SOTNIKOV1, D. N. POLOVYANENKO1, E. G. BAGRYANSKAYA1 1Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia 2Novosibirsk State University, Novosibirsk, Russia 3Institute of Soil Science and Agrochemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
Keywords: persistent organic pollutants, organochlorine pesticides, gas chromatography-mass spectrometry, chernozem, soil, agrochemical indicators, soil monitoring, DDT transformation products, Stockholm Convention
The study was carried out on 100 samples of agrogenic soils collected in 2025 from nine districts in the Novosibirsk Region to determine the residual amounts of organochlorine pesticides (OCPs) and other persistent organic pollutants (POPs). Analysis of basic characteristics (particle size distribution, acidity (pH), salinity level, soil organic matter content) of the soil samples has shown that they form a high-quality representative set of samples for the chernozem soils of the West Siberian forest-steppe zone, which are the basis of arable land found in the Novosibirsk Region. The list of POPs and OCPs under determination included the compounds subject to monitoring under the UN Stockholm Convention on Persistent Organic Pollutants: aldrin, dieldrin, 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT) and its derivatives, hexachlorobenzene (HCB), hexachlorocyclohexanes (HCHs), heptachlor, polychlorinated biphenyls (PCBs), chlorpyrifos, as well as a candidate substance for inclusion in the monitoring list - methoxychlor. It has been demonstrated that the substances that had been long included in the Stockholm Convention monitoring list are not currently in use on the studied agricultural fields. However, there remain “background” levels of HCB, PCBs, DDT concentrations averaging between 0.001-0.050 of the maximum permissible concentrations (MPC) or tentative permissible concentrations (TPC). Several substances (aldrin, dieldrin, methoxychlor) were not detected. Special attention was given to studying DDT and its transformations in natural environments into 4,4'-dichlorodiphenyldichloroethane (DDD) and into 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (DDD) and 1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene (DDE). It has been established that since the discontinuation of DDT-based pesticide application, on average, approximately 60 % of initially introduced DDT had already transformed into DDD and DDE.
S. YU. PETRAKOVA, V. D. TIKHOVA
Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
Keywords: organophosphorus compounds, microwave plasma atomic emission spectrometry, Agilent 4100, phosphorus determination, arylphosphines
Elemental analysis in general, and phosphorus determination in particular, is an important step necessary for establishing the purity of newly synthesised organophosphorus compounds. It has been shown that phosphorus determination by classical spectrophotometry is difficult due to the need to convert all phosphorus to orthophosphate. Microwave plasma atomic emission spectrometry is proposed for determining phosphorus in arylphosphine ligands and their metal complexes after oxidative decomposition of these compounds. This method allows for the determination of total phosphorus regardless of its form. Two approaches were used for mineralisation of the compounds: oxygen flask combustion (Schoeniger method) for arylphosphines and acidic microwave digestion for metal complexes. The atomic emission spectrometer was calibrated using solutions prepared from triphenylphosphine by microwave digestion or by the Schoeniger method. Using this method, 11 arylphosphines of various structures and three nickel complexes with phosphorus contents ranging from 4 to 12% were analysed. The absolute error of determination did not exceed 0.3 wt%. The detection limit and limit of quantification of phosphorus were 0.2 and 0.7 mg/L, respectively; the calculated minimum detectable phosphorus content using the Schöniger decomposition method was 1.5 %.
L. V. POLITANSKAYA1, P. A. FEDYUSHIN1, S. V. KOLYSHKINA2, A. M. KHABIBRAKHMANOVA2, A. R. KAYUMOV2,3, A. R. KURBANGALIEVA2 1Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia 2Kazan (Volga Region) Federal University, Kazan, Russia 3Kazan State Medical Academy - Branch of the Russian Medical Academy of Continuous Professional Education, Kazan, Russia
Keywords: fluorinated heterocycles, thioethers, sulphones, antimicrobial activity, mycelial fungi
The new derivatives of fluorinated heterocyclic compounds of the benzoxathiine, pyridothiazine and benzothiazole series were synthesised, their antibacterial and antimycotic activity against the bacteria Staphylococcus aureus ATCC 29213, Escherichia coli ATCC 25922, as well as against yeast ( C. albicans 4940, C. albicans 722) and mycelial ( Aspergillus niger, Penicillium funiculosum, Fusarium solani ) fungi was evaluated. Moderate inhibitory activity of the sulphonyl derivative of 2,3-dihydrobenzo[ b ] [1,4]oxathiine and 2-alkynylbenzo[ d ]thiazole against mycelial fungi was revealed.
D. A. POTAPOV1,2, A. A. SONINA1, C. S. BECKER1, I. K. SHUNDRINA1, M. S. KAZANTSEV1 1Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia 2Novosibirsk State University, Novosibirsk, Russia
Keywords: 4,5-diazafluorene, Knoevenagel condensation, photoluminescence, charge transport
Two thiophene-containing diazafluorene derivatives were synthesised: 2,7-di(thiophen-2-yl)-9H-(4,5-diazafluorene) (TDAF) and 2-(2,7-di(thiophen-2-yl)-(4,5-diazafluoren-9-ylidene))malononitrile (TDAF-CN). Their crystal structures, optical, physicochemical, and semiconductor properties were studied. The target compounds were obtained using the Kischner-Wolff reduction and Knoevenagel condensation. The crystal structure of the compounds was solved by X-ray diffraction. The formation of π-stacking and C-H···π-interactions was revealed. The compounds were demonstrated to undergo partial thermal degradation during sublimation in an inert atmosphere. TDAF-CN was determined to have a deep lowest unoccupied molecular orbital level of -3.99 eV. The photoluminescence quantum yield for TDAF was determined to be 53 % in solution and 73 % in crystals.
A. A. KHODAKOV1, D. S. BAEV1,2, I. V. SOROKINA1, S. V. AYDAGULOVA1,3, S. A. POPOV1, T. G. TOLSTIKOVA1 1Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia 2Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, SRF “SKIF”, Koltsovo, Russia 3Novosibirsk State Medical University, Novosibirsk, Russia
Keywords: β-alanilamide of betulonic acid, inflammation models, mice, molecular targets
In the models of the mouse paw acute inflammation induced by various phlogogens (histamine, concanavalin A and sheep erythrocytes), the anti-inflammatory activity of the lupane triterpenoid 3-[3-oxo-20(29)-lupen-28-oil]-aminopropionic acid (β-alanilamide of betulonic acid, ABA) was studied. Experiments were carried out with outbred and inbred (strains СВА, С57BL/6) female mice of reproductive age (body weight 20-30 g). The agent was administered orally in the doses of 50 and 100 mg/kg in the form of a water-Tween suspension one hour before subplantar injection of phlogogen into the paw. Indomethacin substance was used as a reference drug. The predicted values of the energy of ABA binding to key targets in the Nrf2 and NFkB signaling pathways were determined using the molecular docking method. It has been shown that when administered orally in the doses of 50-100 mg/kg, ABA has a moderate anti-inflammatory effect in the models of exudative, B-cell and T-cell inflammation, exhibiting higher activity at low doses. The results of molecular modelling of the possible interaction of ABA with inhibitors of nuclear factors Nrf2 and NFkB (proteins KEAP1 and IKK, respectively) show a greater affinity of ABA for KEAP1 than for IKK. It was found that ABA and betulonic acid have similar probable values of targets binding energy, which suggests common mechanisms of anti-inflammatory action. The current study results and the previous data on the low toxicity and wide range of pleiotropic effects suggest that ABA is a promising chemopreventive agent.
L. A. SHUNDRIN, I. A. OS’KINA, I. G. IRTEGOVA
Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
Keywords: thioxanthone, electrochemical reduction, radical anion, cyclic voltammetry, electron paramagnetic resonance spectroscopy
The reaction of 2-(bromomethyl)-9H-thioxanthen-9-one with p-hydroxymethyl benzoate leads to 2-methyl-4-((9-oxo-9H-thioxanthen-2-yl)methoxy)benzoate 1, which is converted into the corresponding S,S-dioxide 2 upon oxidation with hydrogen peroxide. The first stages of electrochemical reduction of compounds 1, 2 in dimethylformamide are reversible one-electron processes with the formation of long-lived radical anions [1].-, [2].-. The second stage of electrochemical reduction of compound 2 is a one-electron irreversible process.
V. A. ZYABLOV, S. V. ALEEVA, S. A. KOKSHAROV
Ivanovo State Polytechnic University, Ivanovo, Russia
Keywords: flax fibre, redox transformation of lignin, oligoacrylate, interaction, IR spectroscopy
The study is part of the project aimed at solving actual problems in overcoming the limitations of the practical application of flax fibre reinforced composites due to their insufficient moisture resistance. We are implementing a biomimetic approach to reproduce the state of the flax xylem cell wall, which has a uniquely stable structure under permanent contact with moisture absorbed from the soil. Carrying out a special bio-treatment of the fibrous material and impregnating it with a low-viscosity binder to block the porous system of elementary fibres can ensure the creation of a polymer exoskeleton that can prevent swelling of the textile base of the composite in a humid environment. The conditions for using oligoacrylates as a low-viscous binder for the flax-containing composite have been determined, implementing an alternative variant of their curing to avoid undesirable consequences of typical polymerisation modes involving peroxide initiators. The experiments simulate the conditions of redox transformation of lignin in the process of biomodification of linen materials in combination with the treatment with oligoether acrylate MGF-9. The method of IR Fourier spectroscopy was used to evaluate changes in the state of one- and bicomponent polymer objects. The integral peaks decomposition makes it possible to isolate the bands of individual vibrations in the interatomic bonds of the studied compounds and quantify the change in their amplitude. The difference between the spectra of the product synthesised through the redox transformations of lignin in the presence of oligoacrylate and the result simulating the sequential modifying treatments of flax fibre material was revealed. Concordant transformations of a number of spectral bands provide evidence of lignin macromolecules defragmentation in combination with the initiated interaction of the oxyaryl units of the biopolymer and vinylidene groups of oligoacrylate, which confirms the formation of a copolymer.
A. YU. RYAZANOVA1, V. V. STROKOVA1, P. S. BASKAKOV2 1Shukhov Belgorod State Technological University, Belgorod, Russia 2Melnikov Central Research and Design Institute of Steel Structures, Moscow, Russia
Keywords: viscosity, polyvinyl alcohol, polymethylsiloxane oil, aqueous emulsion, quenching medium
The analysis of the rheological characteristics is presented, and the possibility and efficiency of using aqueous emulsions of polymethylsiloxane (PMS) oils as a quenching medium during the heat treatment of steel products is established. The emulsion is composed of the dispersed phase (polymethylsiloxane oil of grades PMS-100, PMS-200, and PMS-300), and the dispersive medium (an aqueous solution of SUNDY polyvinyl alcohol PVA 088-05). The aqueous dispersions of PMS oils were obtained by high-speed emulsification. The obtained rheological characteristics of emulsions under the conditions of temperature change (10, 25 and 40 °C) confirm the hypothesis concerning the relationship between the conformational state of the surfactant macromolecules (polyvinyl alcohol) and the aggregate stability of the aqueous emulsion of PMS oil. The results of the study revealed a strict correlation between the rheological characteristics of the emulsion system and its concentration in water, as well as the kinematic viscosity (100, 200, and 300 cSt) of PMS oil under temperature changes. These dependencies for aqueous emulsions based on PMS oil with different initial viscosities follow the Kraemer equation in the logarithmic form with a confidence level R2 > 0.95. It has been experimentally proven that temperature conditions and mechanical loads do not affect the structural state of stabilised emulsion droplets. The system demonstrates high stability, predictable rheological characteristics, and preservation of structural integrity over a wide range of PMS oil concentrations. The emulsifying capacity of polyvinyl alcohol is a constant value and does not correlate with the kinematic viscosity of PMS oil. These findings have practical significance for creating highly effective quenching media with desired thermophysical and technological properties.
D. V. KUZMIN1, O. A. EPOV1, A. A. KUZMINA1, E. V. LAZAREVA2, V. I. KUZMIN1 1Krasnoyarsk Scientific Centre SB RAS, Institute of Chemistry and Chemical Technology SB RAS, Krasnoyarsk, Russia 2V. S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
Keywords: niobium, polyniobates, niobium peroxide compounds, anion-exchange sorption, niobium desorption
The sorption of polyniobates from alkaline solutions by the anion-exchange sorbent AV-17 in the OH- form and activated carbon ABG was studied. Deep extraction of niobium from solutions is achieved from alkaline solutions with a concentration of less than 0.5 mol/L for the sorbent AV-17-8 and less than 2 mol/L for activated carbon. The capacity of the sorbents under these conditions is 95 and 45 g/kg, respectively. The dependences of the extraction depth on potassium hydroxide concentration are exponential, and at KOH content above 5 mol/L, niobium sorption is not observed. Niobium is irreversibly extracted from diluted alkaline solutions by both types of sorbents. It is assumed that the irreversibility of sorption is associated with the accumulation of anionic niobium complexes in the sorbent structure and their subsequent polymerisation in the form of linear long-chain metaniobates. It has been established that even prolonged contact (up to 24 h) of niobium-saturated sorbents with potassium hydroxide solutions (10 mol/L) does not result in noticeable niobium desorption. Heating a niobium-saturated carbon sorbent at 100 °C also does not yield positive results. Niobium desorption is achieved by treating the sorbent with alkaline solutions containing hydrogen peroxide, and is caused by the destruction of polymer molecules and the formation of desorbed niobium peroxide complexes. These systems rapidly reach equilibrium. The developed process can be used to recycle the decomposition products of niobium concentrates during their sintering with alkaline reagents. At present, mixtures of hydrofluoric and sulphuric acids are used to decompose niobium minerals.
A. I. LYSIKOV1,2, A. B. AYUPOV1,2, S. WANG2,3, A. V. SHNAYDER1,2, R. A. MASLENKIN1,2, E. V. PARKHOMCHUK1,2, Zh. ZHOU4, Zh. ZHENG4 1Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia 2Novosibirsk State University, Novosibirsk, Russia 3Heilongjiang University, Harbin, China 4Sun Yat-sen University, Guangzhou, China
Keywords: temperature-programmed desorption, kinetics, ammonia, Polanyi-Wigner model, Schroeder-Eyring model, heterogeneous catalysts, HZSM-5
In this work, an approach to kinetic modelling of temperature-programmed desorption of ammonia (TPD-NH3) on zeolites is proposed, based on the Schroeder-Eyring equation and taking into account the temperature dependence of the pre-exponential factor. It is demonstrated that the use of thermodynamic activation parameters (ΔH0≠ and ΔS0≠) allows the desorption curves obtained at different heating rates to be described with a single set of converging parameters, thus providing a pathway for TPD method standardisation for comparative analysis of the acidic properties of zeolites. The modelling results suggest that the low-temperature peaks are most likely associated with desorption from the outer solvation (fluid) shell around the acid sites of the zeolite, whereas the high-temperature peaks (with activation enthalpies of 136.6 and 214.7 kJ/mol) correspond to ammonia desorption from strong Brønsted acid sites.
