Complex copper-based chalcogenides are a significant environmental-friendly functional material that has great application potential due to their interesting thermoelectric, photoelectric, optical, and other properties, as well as their ionic conductivity. Analysis of numerous studies shows that improving the application characteristics of these compounds is associated with manipulating their structure and composition. An effective solution for optimizing such processes requires their in-depth thermodynamic analysis, which requires reliable data on the fundamental thermodynamic characteristics of the corresponding compounds. This review summarizes the results of researches, including ours works, on the thermodynamic properties of copper chalcogenides with some p1 -p 3 elements. The majority of these works were carried out using various modifications of the electromotive force (EMF) method. Planning of experiments carried out by this equilibrium method of chemical thermodynamics and processing of their data is impossible without the presence of reliable data on phase equilibria. Taking this into account, in addition to thermodynamic data, the work also presents the solid-phase equilibria diagrams for a number of systems studied by the EMF method. The analysis showed that for the Cu-Tl-X, Cu-Ge(Sn)-X (X-S, Se, Te) and Cu-As(Sb, Bi)-S(Se) ternary systems there are mutually consistent data on the phase equilibria and thermodynamic functions of the ternary compounds. For the Cu-Tl-X and Cu-Sn-Se systems, the thermodynamic functions of ternary compounds are obtained by two modifications of the EMF method by determining the partial molar functions of two different components - copper and thallium (tin). The thermodynamic properties of copper chalcogenides with gallium, indium, and silicon have not been extensively researched, and the data that is available is inconsistent.

The catalytic reaction of n-heptane (n-C7H16) oxidation with molecular oxygen has been studied. Various compositions of the polymer catalyst Mn-P4VP/MBAA (where Mn-P4VP is manganese -immobilised poly-4-vinylpyridine and MBAA is N,N'-methylene-bis-acrylamide) containing 2-5 wt% Mn were prepared and tested. The concentration of manganese in the catalyst based on immobilized metal -polymer complexes is within the range of 2-5 wt% Mn. The oxidation reaction was carried out at a ratio of components n-C7H16/O-2/polymer catalyst with Mn = 1 : 3.38 : 0.003 and time 6 h within the temperature range 303-383 K. The data on the yield of the major products of n-heptane oxidation are presented, taking into account the initial components, catalyst composition, temperature and the time of oxygen contact with the reacting components. It has been established that during the oxidation of n-C7H16 (303-383 K), the yield of alcohols is higher than the yield of other oxidation products. The oxidative conversion of n-heptane increases from 45 to 75 mol% with an increase in temperature in the range of 303-383 K. For the multistage oxidation of n-heptane with oxygen, a kinetic model was selected and considered. On the basis of this model, the reaction rate constants were calculated in the range of 303-383 K considering the degree of heptane conversion. The activation energy of n-heptane oxidation was estimated, taking into account the method of choosing the most plausible parameter and experimental data on n-heptane convection.

Areas of uncertainty in the thermodynamic parameters of oxidative reduction reactions of titanomagnetite concentrates were identified using the universal genetic algorithm (MGA). The oxidative reduction reactions of titanomagnetite concentrates for the production of iron, titanium dioxide and sodium vnadate in a reactor flow mode, with a change in the composition and pressure of the reaction products, have been investigated. To determine the temperature dependences of the Gibbs free energy of oxidative reduction reactions in the temperature range 900–1400 K, the Temkin-Shvartsman equation was used, modified taking into account the thermodynamic functions of the formation of solid solutions and the value of the vapor pressure of gaseous components. It was revealed that the ranges of temperature and pressure uncertainty for direct reduction of Fe3O4 to free iron, oxidation of V3+ to V5+ in granules of titanomagnetite concentrates are: P = 0.1 ÷ 1 atm, T = 1000 ÷ 1400K.

An analysis of the behavior of non-Newtonian oils in the process of formation and destruction of their structure with the participation of resinous-asphaltenic materials has been performed. The conditions of formation of coagulation structures and the possibilities of their destruction were determined. A general rheological equation defining the possible behavior of non-Newtonian oils in different cases has been derived, and its effectiveness was substantiated with the use of available experimental data. The dependences of the effective viscosity of non-Newtonian oils on the rate of their shear and the content of resinous-asphaltenic materials in them were constructed. It was established that the asphaltenes, resins, and paraffins, contained in an oil, substantially influence its rheological properties and, consequently, the movement of the oil and its transportation.

Oxidation of n-octane was carried out in a stationary reactor using immobilized manganese nanoparticles in various mass percentages (5 and 10 wt.%) on poly(4-vinylpyridine). It was found that manganese-containing catalysts immobilized in polymer are more active in the oxidation of n-octane than similar homogeneous catalysts. A kinetic model and an equation for calculating the oxidation of n-octane in the presence of a manganese-polymer catalyst were chosen for the calculation. Taking into account the kinetic model, the velocity constant of the specified process is calculated. A high conversion in the oxidation reaction of n-octane with molecular oxygen was obtained

The boundaries of stable and metastable states of solid solutions of the MnTe-Sb2Te3 and SnTe-Sb2Te3 systems were determined by solving the thermodynamic equations of phase equilibria using the multipurpose genetic algorithm (MGA). As initial information, we used a small amount of experimental data from DTA and X-ray diffraction analysis, and thermodynamic functions of formation of MnTe, SnTe, Sb2Te3, MnSb2Te4, MnSb4Te7 SnSb2Te4, and SnSb4Sb7 compounds. The temperature-concentration dependences of the Gibbs energy of the formation of solid solutions from binary compounds, as well as from simple substances in quasi-binary sections, were determined using a subregular model of solutions of nonmolecular compounds as applied to telluride systems. The coordinates of the boundaries of metastable and stable solid solutions, in contrast to the entropy, are not very sensitive to the error in determining the enthalpy of formation of binary and ternary tellurides of manganese, tin, and antimony. It was revealed that the boundaries of β (Sb2Te3) solid solutions in MnTe-Sb2Te3 system extend to 10 mol

The results of a study of the physicochemical properties of natural bentonite clay of the Dash-Salakhli deposit of the Republic of Azerbaijan and synthetic montmorillonite (MT) Na 1.0 Al 1.0 Mg 1.0 Si 4 O 10 (OH) 2 H 2 O obtained under hydrothermal conditions are presented. The chemical and phase compositions of the samples are compared, the porous-textural and sorption characteristics are studied, the distribution of acid sites on the surface of the samples is studied, and the results of the study by IR absorption spectroscopy are presented. The sorption capacity of the samples is compared to the organic cationic dye methylene blue and the heavy metal ions from the model solutions simultaneously containing lead and copper ions. Based on the results obtained, conclusions are drawn on promising areas for the use of natural and synthetic MTs.

The properties of hexagonal gallium monosulphide (GaS) were modeled within the framework of the density functionality theory (DFT) taking into account the impact of vacancies related to a short range ordered structure. It is shown that electron irradiation of a GaS monolayer causes a decrease in conductivity due to formation of point defects. The band structure, density of states and energy properties of GaS supercells with 36 and 48 atoms with monovacancies were calculated. DFT calculations were performed to obtain values of the formation energy of GaS and Ga and S atom vacancies, as well as to determine the degree of vacancies' impact on the properties. Impact of GaS compound composition on the chemical potential value was studied taking into account the Ga-S phase diagram. Key words: modeling, DFT calculation, GaS supercells, point defects, energy structure, density of states, formation energy, chemical potential.

Catalysts with manganese nanoparticles (5 and 10 wt %) immobilized on poly-4-vinylpyridine were prepared. When interacting with molecular oxygen, the catalyst forms active oxygen, which is involved in the low-temperature oxidation of n-heptane. These catalyst compositions have been used to oxidize n-heptane with pure oxygen to give alcohols, aldehydes and ketones. Oxidation of n-heptane was carried out in the temperature range 303-383 K, molar ratios of heptane:oxygen = 1:3.38, and at atmospheric pressure. It has been found that the non-crosslinked (MnP4VP polymer poly-4-vinylpyridine) and N,N-methylene-bis-acrylamide-crosslinked MnP4VP/MBAA metal-polymer catalyst containing 5 wt % Mn2+ exhibits the highest activity in n-heptane oxidation reactions. The kinetic parameters of the reaction of n-heptane oxidation with oxygen at low temperatures were studied using a kinetic model based on the heptane conversion data. The kinetic model was compiled on the basis of experimental data: heptane:oxygen = 1:3.38 at atmospheric pressure using Mn (wt. 5%) P4VP/MBAA in the temperature range 303-383 K. Within the framework of the chosen kinetic model effective rate constants of the oxidation reaction with the formation of alcohols was calculated

В рамках теории функционала плотности (DFT) моделированы свойства гексагонального моносульфида галлия (GaS) с учетом влияния вакансий, связанных с ближнеупорядоченной структурой. Показано, что электронное облучение монослоя GaS приводит к уменьшению проводимости за счет образования точечных дефектов. Рассчитаны зонная структура, плотность состояний и энергетические свойства суперъячеек GaS с 36 и 48 атомами с моновакансиями. DFT-расчетами получены значения энергии образования GaS и вакансий атомов Ga и S, а также определена степень влияния вакансий на свойства. С учетом фазовой диаграммы Ga-S изучено влияние состава соединения GaS на величину химического потенциала. Ключевые слова: моделирование, DFT-расчет, суперъячейки GaS, точечные дефекты, энергетическая структура, плотность состояний, энергия образования, химический потенциал.

The problems of analysis and solution of the equation of hydraulic diffusion for the oil bed as an isotropic porous medium with different boundary conditions are considered A collection of analytical solutions and the possibilities of using them to construct a pressure recovery curve for estimating the coefficients of hydraulic diffusion and permeability of the bed are given. The one-dimensional solutions of these equations are compared with experimental data obtained on an operating setup, and their satisfactory convergence is demonstrated. The solutions obtained can be used to solve various problems of oil filtration in an isotropic porous medium. The structure formation of the non-Newtonian oil due to asphalt-resinous substances and their influence on the filtration rate of oil and its rheological properties have been investigated New rheological equations for non-Newtonian oil filtration in a porous medium have been suggested.

Solid-phase equilibria in the Tm–Te system and the thermodynamic properties of thulium tellurides are studied via electromotive force (EMF) method and X-ray phase analysis. Experimental data show that compounds TmTe, Tm2Te3, and TmTe3 form in the system. The partial thermodynamic functions of TmTe and Tm in alloys are found for the first time from EMF measurements in concentration cells, relative to TmTe and Tm electrodes at 300–450 K, from which standard thermodynamic functions of formation and standard entropies of intermediate compounds are calculated.

— The Bi–S–Te system has been studied using emf measurements in the composition region Bi 2 S 3 –Bi 2 Te 3 –Te–S at temperatures in the range 300–450 K. We have calculated relative partial molar functions of bismuth in alloys and used the results to obtain self-consistent sets of the standard Gibbs free energy, standard enthalpy, and standard entropy of the Bi 2 S 3 , Bi 2 Te 3 , and Bi 2 Te 2 S compounds and a solid solution with the composition Bi 2 Te 1.8 S 1.2 , based on the last compound. The data obtained for Bi 2 S 3 and Bi 2 Te 3 have been compared to data available in the literature. The thermodynamic functions of Bi 2 Te 2 S and Bi 2 Te 1.8 S 1.2 have been determined for the first time.

The thermodynamic properties of a Bi–Se system are studied within 50–65 at % Se at 300–450 K using electromotive force measurements. The relative partial molar functions of bismuth in alloys are calculated, from which mutually consistent standard Gibbs free energies, enthalpy, and standard entropies are obtained for the compounds Bi2Se3, Bi3Se4, Bi8Se9, and BiSe. The data obtained for Bi2Se3 are compared to those in the literature, and the thermodynamic functions for other compounds are found for the first time.

Phase equilibria in the FeS–Ga2S3–In2S3 system were investigated by differential thermal analysis and X-ray powder diffraction analysis. A number of polythermal sections, the isothermal sections at 900 and 1070 K, and the projection of the liquidus surface of the phase diagram were constructed. It was determined that this system is quasi-ternary, and that the liquidus surface consists of the fields of primary crystallization of six phases. Wide regions of solid solutions based on binary and ternary compounds (FeGa2S4 and FeIn2S4) were found, which are of interest as magnetic materials.

Using the Multipurpose Genetic Algorithm (MGA), analytical models of phase diagrams of the Tl9SmTe6–Tl8Pb2Te6, Tl9SmTe6–Tl9BiTe6 and Tl8Pb2Te6–Tl9BiTe6 systems were obtained as temperature dependence on the composition. The boundaries of the uncertainty band for the liquidus surface of crystallization of solid solutions and the TlSmTe2 compound, as well as the solidus of solid solutions, are determined. According to the model of regular solutions of non-molecular compounds, the thermodynamic functions of mixing solid solutions depending on the composition and temperature are determined. It was found that solid solutions of based on the compounds Tl9SmTe6, Tl8Pb2Te6 and Tl9BiTe6 have thermodynamic stability in the entire concentration range. The analytical multi-3D model of the phase diagram of the Tl9SmTe6-Tl8Pb2Te6-Tl9BiTe6 system was determined and visualized for both the quasi-ternary and nonquasi-ternary high-temperature part of the TlSmTe2 crystallization.

Ab initio-методом псевдопотенциала в рамках DFT моделированы свойства гексагонального графена с учетом влияния вакансий, связанных с ближнеупорядоченной структурой. Рассчитаны магнитные свойства суперъячеек графена с 18, 54 и 96 атомами углерода с моно- и дивакансиями. Внесения вакансий углерода на монослой графена вызывает появление локального магнитного момента. Численные оценки величины магнитного момента выполнены для суперъячеек графена с 18, 54 и 96 атомами углерода с вакансиями. Получены значения магнитных моментов и определена область локализации спиновой плотности в суперъячейке с 96 атомами углерода, включающей как ближнерасположенные, так и дальнерасположенные вакансии. Изучено влияние расстояния между вакансиями на величину магнитного момента в суперъячейке графена. Исследованы зависимости магнитного момента и расстояния между вакансиями в суперъячейке графена с 96 атомами от концентрации вакансий. С помощью расчетов энергии образования вакансий углерода в суперъячейке графена изучены ее зависимости от деформации ячейки графена. Ключевые слова: ab initio-расчет, теория функционала плотности, суперъячейки графена, вакансии, магнитный момент, спиновая плотность, расположение вакансий, энергия образования и концентрация вакансий, деформация ячейки графена.