Composition Of Mixture Research Articles

Manufacturing of die blanks from hard alloy granulated mixture and influence of chemical composition of the mixture on technological properties of hard alloy die blanks

The technology of manufacturing dies from a hard alloy granulated mixture includes the following operations: preparation of raw materials, forming of blanks, and subsequent sintering. The preparation of hard alloy mixtures consisting of carbide powders and binder metals is one of the main operations in the production of hard alloys. The properties of the resulting alloys largely depend on the conditions of performing this operation. All operations are interconnected, and any change in technological parameters can lead to a change in the formation of the final material structure and, consequently, its properties. This article discusses the technology of manufacturing and the production process of die blanks from a hard alloy granulated mixture. The results of laboratory studies of the hard alloy mixture, the manufacture, and production tests of die blanks are described.

A closer look at how the dispersive liquid-liquid microextraction method works. Investigation of the effect of solvent mixture composition on the quality and stability of the cloudy state.

The dispersive liquid-liquid microextraction (DLLME) is one of the most popular miniaturized extraction procedures. In this paper, the degree of dispersion and dispersion stability were studied with the aim to assess the correlations of these parameters with efficiency for the selected analytical application. The dependence between the degree of dispersion (cloudy state quality) and its stability obtained by various emulsification procedures, such as solvent-assisted emulsification (using various dispersive solvents) and mechanical emulsification (using auxiliary energies), is investigated and discussed. It was found out that the degree of dispersion depends on the type of emulsification procedure and decreases in the series: solvent-assisted (SA-) = ultrasound-assisted (UA-) > air-assisted (AA-) > vortex-assisted (VA-) emulsification. The emulsion stability depends on the degree of dispersion and there were 1810 and 2070s for the most effective emulsification procedures, such us solvent-assisted and ultrasound-assisted emulsification, respectively. A comparison between the sensitivity of the analytical methods (using spectrophotometric determination of the anionic surfactants) and the degree of dispersion have been made. The sensitivity of the methods was ranked as follows: DLLME > UA-LLME > VA-LLME > AA-LLME.

Chirality Sensing of Cryptochiral Guests with Prism[n]arenes.

Optical chirality sensing has gained significant attention in recent years. Within this field, the quest for stereodynamic chiroptical probes capable of detecting cryptochiral guests presents a formidable challenge. Macrocycles exhibiting planar chirality have emerged as promising candidates for amplifying the chirality of cryptochiral guests. In this study, we demonstrate that the formation of host-guest complexes between cryptochiral molecules and planar chiral prismarenes triggers electronic circular dichroism (ECD) signals via host-guest complexation-induced chirality amplification. The absolute configuration of the most stable chiral macrocyclic host-guest complex has been established by resorting to both exciton model and DFT computations. Furthermore, we demonstrated that this supramolecular chirality sensing system can be employed to determine the enantiomeric composition of scalemic mixtures by measuring the ECD bands intensity. The information described here opens the way for the use of prismarenes as stereodynamic probes for sensing of cryptochiral guests.

RESEARCH OF HEAT RESISTANCE OF CARBON-CARBON COMPOSITE MATERIALS WITH PROTECTIVE COATINGS OBTAINED USING FUNCTIONALLY ACTIVE CHARGES

This study focuses on the development of protective coatings for carbon-carbon composite materials (CCСM) used in high-temperature processes in aerospace engineering. CСCM have limitations due to their susceptibility to oxidation, erosion, and burnout in gas streams. Our research is aimed at creating protective coatings using functionally active charges (FAC) obtained under non-stationary temperature conditions and improving the performance of composites. The aim of our study is to identify the optimal compositions of powders for chromium-alloyed protective coatings using functionally active charges to increase the heat resistance of the working surface. We analyzed various methods of obtaining protective coatings, including chemical-thermal and liquid-phase saturation methods, to find out their peculiarities in interaction with the CCСM matrix and changes in their mechanical properties. In addition to the traditional methods, we have investigated the method of saturating the surface with a solid phase in an active gas environment using FAС, which are obtained under non-stationary temperature conditions. This method provides high quality coatings, reduces processing time and makes it possible to work at high temperatures depending on the composition of the spray coatings. Much attention was paid to the problem associated with chemical interaction and formation of carbide phases, which are important for ensuring the stability of coatings under high temperature conditions. Experimental studies include a factorial experiment to determine the compositions of powder mixtures that provide high heat resistance. Various independent variables, such as the content of chromium, silicon, titanium, and aluminum, were considered, taking into account their influence on the physical and mechanical properties of coatings. Particular attention was paid to the optimization of the parameters of thermal autoinitiation of the functionally active charge under process conditions. Regression equations are presented to evaluate the dependence of the wear resistance of coatings on the autoinitiation parameters and the content of alloying elements. The analysis of the study results includes the construction of three-dimensional graphical dependencies for optimizing the composition of powdered CBA in the Cr-Al-Ti and Cr-Al-Si systems. In practice, chromium-aluminum-siliconized coatings obtained under isothermal conditions, when tested for heat resistance, have a more porous surface through which oxygen penetrates to the surface of the HCCM. Compared to the coatings obtained using FAS, the heat resistance is 1.5-1.7 times higher, which can be explained by the higher concentration of chromium, aluminum, silicon, and titanium, which contribute to the formation of protective oxide membraness. The low-porosity surface of the coatings obtained using functionally active layers prevents oxygen from entering the material, contributing to the formation of oxide protective membranes such as SiO2, TiO2, Cr2O3, Al2O3.

Pollutant removal efficiency of bare and planted rain gardens with diverse planting mixtures.

This study examines the influence of planting mixture variations on the quality of the percolated water of the rain garden with and without plants. Six planting mixtures in experimental rain gardens have been used. It has been noted that pollutant removal efficiency of RG can exhibit variations based on specific parameters. Notably, RG6, utilizing a planting mix of 75% topsoil and 25% compost, demonstrated the highest performance. These results draw attention to the critical role of the specific planting mixtures in influencing the performance of vital parameters related to pollutant removal. The observation shows that RG5 exhibits exceptional removal efficiency in pH, Total Suspended Solids (TSS), Biological Oxygen Demand (BOD), and Chemical Oxygen Demand (COD), and RG6 performs best in electrical conductivity (EC), Total Dissolved Solids (TDS), Total Nitrogen (TN), and Total Phosphorus (TP) removal. In particular, when analyzing pollutant removal on a surface with Madagascar periwinkle plants, RG6 emerges as the most effective, achieving an impressive efficiency of approximately 49%. For the bare surface, pollutant removal efficiency is 40%. The study outcome will be useful in deciding the composition of the planting mixture, which will keep the rain garden to improve quality and quantitatively hydrological performance, lowering urban flooding magnitude.

Pemanfaatan Campuran Pati Singkong Dan Pati Ubi Jalar Sebagai Bahan Baku Pembuatan Plastik Biodegradasi

Plastic waste is already polluting the environment both land and oceans, as plastic consumption continues to increase. Biodegradable plastics are an effort to reduce environmental pollution, biodegradation plastics are plastics made from natural materials usually biodegradable plastics made from natural starch. Cassava starch is the most widely used type of starch and is developed for the manufacture of biodegradable plastics, and sweet potatoes are tubers whose starch content is quite numerous even though it has not been widely developed into plastic material. This research aims to produce natural plastics that can replace conventional plastics and reduce environmental pollution due to plastic waste. The study was conducted with variations in the composition of starch mixtures (50:0 gr, 35:15 gr, 25:25 gr, 15:35 gr, 0:50 gr) and variations in drying temperatures (40°C, 50°C, 60°C).In this study carried out organoleptic test, thickness value test, water absorption value test and degradation test. The results of this study showed biodegradable plastics that have the best characteristics are in the variation of the composition of the mixture 50:0 gr at a drying temperature of 60°C, with a thickness value of 0.11 mm and a water absorption value of 36.5%, but the rate of degradation in this variation is very slow

X-ray characterization of a bulk resistive MICROMEGAS operating at low gas pressure

In the last decades, interest has grown in the development of detectors that can accurately measure energy and track of low-energy (1–100 keV) charged particles. In this paper we present our effort to construct a resistive MICROMEGAS detector with a wide amplification gap (192μm), to achieve high gain with a low discharge probability, even when operating with a low-pressure gas down to 50mbar. The detector response (gain, energy resolution, relative primary charge collection efficiency) to X-rays from a 55Fe source was measured under different operating conditions of amplification and drift fields, gas pressure and gas mixture composition. The results obtained and their temporal stability demonstrate that the detector can be used for the measurement of low-energy radiation with good energy resolution.

Mechanical Characteristics Of Composite Materials Made From Polyester Resin Mixed With Cocopeat On Static Loads

Cocopeat is a binder between coconut fibers in coconut fiber. Cocopeat has high lignin and cellulose content and is resistant to bacteria and fungi. The aim of the research was to determine the mechanical characteristics of cocopeat mixtures with various dosage ratios of 20%, 40%, 60% to 80%. Mechanical characteristic testing is carried out by applying a load to specimens that have been made in accordance with ASTM D 638-03 standards. The maximum load given is 980N. The test results show that the highest stress value is found in the 40% cocopeat mixture composition, which is 8.1902 Mpa and the highest elastic modulus is found in the 20% cocopeat mixture composition, which is 13.8x10-3 Gpa, while the lowest tensile stress value is found in the 60% cocopeat mixture. and the lowest modulus of elasticity was found in a composition of 80% cocopeat mixture, namely 5.12 x 10-4 Gpa. Thus, more and more cocopeat powder is added to composite materials made from polyester resin. This causes a decrease in the value of stress and modulus of elasticity.

Optimization of Aggregate Composition of Asphalt Concrete Mixtures to Ensure Maximum Density

high strength and stability of asphalt concrete, but also at ensuring optimal characteristics of its structure.The main principles for the optimization of the grain composition are based on the parameters of the size and shape of thе stone aggregate particles included in the composition of asphalt concrete mixtures. An in-depth analysis of the grain composition helps to achieve an optimal balance between coarse and fine fractions, which in turn ensures the stability and durability of the asphalt concrete pavement. The maximum density of an asphalt concrete mixture plays a key role, influen-cing its physical and mechanical properties and ability to withstand aggressive environmental influences and traffic loads. In addition, the density of the mixture significantly affects its resistance to static and dynamic loads and deformations, which is important for ensuring road safety. The paper provides an analytical review of the basic principles and methodology for determining the grain composition of fine-grained asphaltic concrete mixtures with grain sizes up to 10 mm in order to achieve their maximum density. Both domestic and foreign methods for optimizing mixture design parameters are considered. Based on the consideration of ideal mathematical curves the grain composition, the main regularity for fine-grained asphalt concrete has been established, which has similar parameters to the mathematical Fourier curve. Understanding and practical application of the principles of constructing the grain composition of asphalt concrete mixtures of maximum density not only improves the quality of road construction, but also contributes to a more efficient use of resources, ensuring the stability and durability of the pavement. This leads to a reduction in road maintenance and repair costs, which is an important aspect in the context of the economic efficiency of infrastructure projects. Thus, improving the methods for investigating and controlling the grain composition of asphalt concrete is important for the sustainable development of road construction.

ASSESSMENT OF THE POSSIBILITY OF USING RECYCLED COARSE AGGREGATE IN A WOOD-SOIL CONCRETE SLAB

Problem statement. During the process of post-war reconstruction in Ukraine, there will be a need for a large number of affordable and ecological building materials, especially in the part of restoration and construction of low-rise buildings. Such building materials can be soil-concrete and aggregates from crushed concrete waste. The proposed constructive solution of the ribbed floor, in which the ribs are made of pine beams and OSB sheets, and the slab part is made of soil concrete on fixed formwork. The purpose of the article is to determine the optimal composition of the soil-concrete mixture using crushed stone obtained after crushing concrete scrap, taking into account the configuration of the wood-soil concrete slab, to determine the strength of soil-concrete of this composition, to determine the possibility of using recycled coarse aggregates. Conclusions. Based on the results of determining the optimal composition of soil-concrete, it was established that the maximum compressive strength is achieved when the mass content of the binder in the cement-soil mixture is at the level of 20 %. Taking into account the configuration of the slab part of the floor, a fraction of 5...7.5 mm is accepted for coarse aggregate. During the test of soil-concrete samples with recycled aggregate with a mass content of 10 %, 20 % and 30 %, the compressive strength of soil concrete decreased. Obviously, the presence of a clay component (loam) in the mixture reduces the adhesion in the contact zone between the aggregate and the soil-concrete, which increases the heterogeneity of the entire structure of the soil-concrete. Thus, the use of natural or recycled coarse aggregates in soil-concrete is impractical. Taking into account the determined strength of soil-concrete without aggregate, a scheme of combined concreting of the soil-concrete slab is proposed – heavy concrete above the rib and soil-concrete in the overhangs. In this case, there is a need for research on the possibility of using recycled coarse aggregate of the required size in heavy concrete.

A A Novel Poly (vinylidene) Fluoride/TiO2/Spent Bleaching Earth for Enhancing Hydrophilic Hollow Fibre Membrane

Nowadays, polymer as the raw material has been utilized in the development of Hollow Fibre (HF) membranes. PVDF is a commonly used for HF membrane material. However, it has hydrophobicity properties and lead membrane becomes low permeability and fouling. Therefore, to avoid these membranes problems, the incorporation of inorganic nanoparticles into PVDF membranes matrix is necessary to be applied for significantly improving PVDF membranes performance. This study investigates the characteristics and performance of PVDF-TiO2 HF membranes using spent bleaching earth (SBE) as a promising material from industrial waste as a renewable inorganic nanoparticle. This novel PVDF-TiO2-SBE HF membrane was fabricated using the subsequent steps: The preparation process incorporates SBE revival through solvent extraction and thermal treatment alongside the wet spinning technique for membrane fabrication. The Fourier transform infrared (FTIR) functional groups, scanning electron microscope (SEM) morphology, water contact angle and pure water flux performance were investigated to specifically understand the performance of this typical HF membranes. The IR results show that Si-O-Si groups were found in the membrane matrices due to the addition of SBE material. The addition of TiO2-SBE particles also indicate a sandwich (sponge-finger-like) morphological structure on the cross-sectional, a rough and porous surface structures. The hydrophilic properties of the HF membrane and pure water flux performance are determined by the composition of the TiO2-SBE mixture added as an additive material. The minimum contact angle found at 74.33°, while the water flux is 5.81 kg.m-2.h-1 on the identical HF membrane. Accordingly, this approach significantly enhances the properties of the pure PVDF HF membrane.

Diagnostyka stanu technologicznego gazociągów na podstawie składu transportowanych mieszanin gazowych

The efficiency of natural gas transportation hinges largely on the quality of technological processes involved. Imperfect separation process can lead to the liquid particles remaining in the gas and entering the transport systems, causing various technological issues with gas pipelines (clogging, hydrate formation, corrosion wear, etc.). The presence of mechanical particles in gas mixtures accelerates the degradation of metallic components of the transport system due to erosion. Additionally, the multiphase nature of gases contributes to complications during transportation, altering the quality indicators when different gas qualities are mixed. Consequently, the composition of gas mixtures, their mechanical particles, moisture, and other indicators, deviate non-linearly from their initial values. The technological condition of the main gas pipelines significantly impacts their discharge capacity and hydraulic characteristics. Failure to clean natural gas to current standards and requirements at production stations can result in condensation of water and hydrocarbon vapours in pipelines, leading to the accumulation of the liquid phase in the cavities of the pipeline and the formation of blockages due to hydrate compounds formation, the reduction of the cross-section of the gas pipeline or its complete blockage. Sediment accumulation on the inner surfaces of gas pipelines installed in complex geographical conditions adversely affects transportation system, increasing maintenance, energy, and transportation costs. Utilizing gas composition as an auxiliary tool (indicator) for diagnosing various technological processes and predicting transport parameters has been investigated in numerous research works in the oil and gas production industry.

Experimental Study on Surface Segregation Law of Three-Dimensional Accumulation Body of Sand and Stone Particles by Binary Mechanism

Sand and stone materials are one of the important raw materials for infrastructure construction. In recent years, natural sand resources have decreased rapidly. In order to protect rivers and DAMS and ecological balance, local governments have increased the control power of natural sand mining, and replacing natural sand with mechanically broken parent rock formation mechanism sand has become an inevitable trend of the industry development. During the crushing process of parent rock, sand particles of different particle size range are produced, and particle segregation occurs in the process of stacking in the yard, which brings great trouble to the calculation of particle grading and material sample detection, and hinders the large-scale application of machine-made sand. In this paper, three-dimensional stacking tests of irregular particles were carried out to identify the particle distribution on the surface of the stack by digital image technology, analyze the relationship between particle size composition of particle mixture and the particle distribution of the accumulation body, and study the distribution law and segregation characteristics of the accumulation body. The experimental results show that the mixture with different coarse particle content will produce the corresponding distribution on the surface of the accumulation body after the accumulation. On the surface of the accretion body, the content of coarse particles is vertically distributed along the height of the accretion body. The content of coarse particles in the lower part of the accretion body is greater than that in the upper part of the accretion body. The overall segregation coefficient on the surface of the pile decreases with the increase of coarse particle content, and the variation is the largest in the lower part of the pile surface with the initial coarse particle content. Based on the test results in this paper, it provides a basis for formulating the sampling and inspection method of machine-made sand, ensuring the quality of machine-made sand and improving the utilization rate of machine-made sand.

Amelioration of Flexural Performance for Reinforced Concrete Beams by Soffit Bonded High Performance Self Compacting Concrete Prisms

Abstract This paper presents a strengthening technique using a high-performance fibre-reinforced cement-based composite (HPFRCC) mixture. To evaluate the performance of this approach, two types of concrete mixtures were used one high performance and other high strength in strengthening process and compared to strengthening using CFRP laminate. The results showed that the strengthening was in the proportions (42 %, 58.03 %, 74.32 %) for (Mhs, Mcfrp, Mhp), respectively, Where the strengthening improved the bending capacity for beam (Mhp) to a greater extent of the other types and it reduced the appearance of cracks in the beam when loading until occur failure. As appeared failure modes in all elements were due to rupture in the flexure region and crush in the compression region. In addition, ductility index of the strengthened beams was acceptable and energy absorption of the strengthened samples high if compared to the reference beam Therefore, it can be said that this technology may provide a safer alternative for flexural strengthening of RC beams.

A combo Zr–zeolite and Zr(OH)4 mixture composition for one–pot production of γ–valerolactone from furfural

The one–pot cascade transformation of biomass–derived furfural (FUR) to γ–valerolactone (GVL) has attracted great attention but always facing relative low reaction rates. In this work, a combo ZrO2 supported on ZSM–5 nanosheet (ZrO2/NS) and Zr(OH)4 were mixed as a hybrid catalysts system, which was prepared by impregnation and precipitation, respectively. Then the catalytic system was used for conversion of FUR to produce GVL through catalytic transfer hydrogenation in isopropanol. NS zeolite with hierarchical pores promoted the dispersion of ZrO2 and exposed surface assisted the conversion of FUR to isopropyl levulinate (IPL). Moreover, the addition of Zr(OH)4 facilitated the cascade transformation of the intermediate IPL to GVL through the enhanced adsorption of IPL and isopropanol with the cooperation of basic sites. The ZrO2/NS and Zr(OH)4 catalyst system with optimized proportion delivers >90 wt% yield of GVL at 180 °C after 2h reaction, with generation rates of GVL (RGVL) up to 9.2 mmol g−1 h−1.

Influence of Mixture Compositions on Impact Resistance and Mechanical Properties of Concrete Cured in Cold Temperature Conditions

Influence of Mixture Compositions on Impact Resistance and Mechanical Properties of Concrete Cured in Cold Temperature Conditions

Mutual Diffusivities of Mixtures of Carbon Dioxide and Hydrogen and Their Solubilities in Brine: Insight from Molecular Simulations.

H2-CO2 mixtures find wide-ranging applications, including their growing significance as synthetic fuels in the transportation industry, relevance in capture technologies for carbon capture and storage, occurrence in subsurface storage of hydrogen, and hydrogenation of carbon dioxide to form hydrocarbons and alcohols. Here, we focus on the thermodynamic properties of H2-CO2 mixtures pertinent to underground hydrogen storage in depleted gas reservoirs. Molecular dynamics simulations are used to compute mutual (Fick) diffusivities for a wide range of pressures (5 to 50 MPa), temperatures (323.15 to 423.15 K), and mixture compositions (hydrogen mole fraction from 0 to 1). At 5 MPa, the computed mutual diffusivities agree within 5% with the kinetic theory of Chapman and Enskog at 423.15 K, albeit exhibiting deviations of up to 25% between 323.15 and 373.15 K. Even at 50 MPa, kinetic theory predictions match computed diffusivities within 15% for mixtures comprising over 80% H2 due to the ideal-gas-like behavior. In mixtures with higher concentrations of CO2, the Moggridge correlation emerges as a dependable substitute for the kinetic theory. Specifically, when the CO2 content reaches 50%, the Moggridge correlation achieves predictions within 10% of the computed Fick diffusivities. Phase equilibria of ternary mixtures involving CO2-H2-NaCl were explored using Gibbs Ensemble (GE) simulations with the Continuous Fractional Component Monte Carlo (CFCMC) technique. The computed solubilities of CO2 and H2 in NaCl brine increased with the fugacity of the respective component but decreased with NaCl concentration (salting out effect). While the solubility of CO2 in NaCl brine decreased in the ternary system compared to the binary CO2-NaCl brine system, the solubility of H2 in NaCl brine increased less in the ternary system compared to the binary H2-NaCl brine system. The cooperative effect of H2-CO2 enhances the H2 solubility while suppressing the CO2 solubility. The water content in the gas phase was found to be intermediate between H2-NaCl brine and CO2-NaCl brine systems. Our findings have implications for hydrogen storage and chemical technologies dealing with CO2-H2 mixtures, particularly where experimental data are lacking, emphasizing the need for reliable thermodynamic data on H2-CO2 mixtures.

High-Efficiency Effect-Directed Analysis Leveraging Five High Level Advancements: A Critical Review.

Organic contaminants are ubiquitous in the environment, with mounting evidence unequivocally connecting them to aquatic toxicity, illness, and increased mortality, underscoring their substantial impacts on ecological security and environmental health. The intricate composition of sample mixtures and uncertain physicochemical features of potential toxic substances pose challenges to identify key toxicants in environmental samples. Effect-directed analysis (EDA), establishing a connection between key toxicants found in environmental samples and associated hazards, enables the identification of toxicants that can streamline research efforts and inform management action. Nevertheless, the advancement of EDA is constrained by the following factors: inadequate extraction and fractionation of environmental samples, limited bioassay endpoints and unknown linkage to higher order impacts, limited coverage of chemical analysis (i.e., high-resolution mass spectrometry, HRMS), and lacking effective linkage between bioassays and chemical analysis. This review proposes five key advancements to enhance the efficiency of EDA in addressing these challenges: (1) multiple adsorbents for comprehensive coverage of chemical extraction, (2) high-resolution microfractionation and multidimensional fractionation for refined fractionation, (3) robust in vivo/vitro bioassays and omics, (4) high-performance configurations for HRMS analysis, and (5) chemical-, data-, and knowledge-driven approaches for streamlined toxicant identification and validation. We envision that future EDA will integrate big data and artificial intelligence based on the development of quantitative omics, cutting-edge multidimensional microfractionation, and ultraperformance MS to identify environmental hazard factors, serving for broader environmental governance.

A Research Report Comprising on Behaviour of Sea Sand and Normal Sand

Abstract: Consumption of concrete has grown rapidly over a year, and it is also becoming one of the basic constructionmaterials. Since, it is a composite mixture of the constituents containing cement, fine aggregate, coarse aggregate and water. For manufacturing the concrete the fine aggregate are required more quantity. In general, river sand and RIVDER SAND is used as fine aggregate in construction industry. Due to this increase in use of river sand and RIVDER SAND the requirement has been increasing massively day by day in building sector. The government also have given some limitation on mining of river sand from the river beds. The treatment needed to remove the salt content in sea sand and sea water is difficult on time oftreatment and cost. So, the untreated sea sand is used in this test. The work on this study evaluates the different comparisons of mechanical properties of complete RIVDER SAND , complete sea sand (SS) and50% of RIVDER SAND with 50% of sea sand (MSSS). Main intention to consider the sea sand based concrete is to preserve the environmental resource in economical and sustainable development in construction and concrete sector. The experimental test results of sea sand based concrete shows adverse increase in strength compared to RIVDER SAND based concrete specimens

EFFECT OF THE FEED GAS MIXTURE COMPOSITION AT METHANOL DEHYDROGENATION TO FORMALDEHYDE ON SUPPORTED OXIDE CATALYSTS

The article presents the results of a study of the activity of deposited oxide catalysts in the process of obtaining formaldehyde from methanol. Model catalysts were prepared by impregnation of finely porous silica gel with nitrate solutions of zinc, copper, silver, sodium, followed by heat treatment. The catalytic properties of the samples were studied in the reaction of methanol dehydrogenation in the flow mode on a fine fraction of the catalyst. With the complication of the composition of the feed gas mixture, part of argon was replaced with hydrogen, mono- and carbon dioxide. The reaction mixture was analyzed by gas chromatography, IR spectroscopy and photocolorimetry. At a temperature of ~350 °C, a noticeable formation of formaldehyde begins, upon reaching a temperature of 500 °C in the reactor, methanol processing begins to decrease, while the concentration of formaldehyde changes insignificantly. Along with formaldehyde, dimethyl ether, methane and carbon dioxide are fixed in the reaction products. At the end of the tests on the surface of the catalyst, carbon, oxygen and hydrogen are quantified using elemental analysis methods, the ratio between which corresponds to the formula (-COH-)n. That is, along with the target reaction, methanol is consumed for the formation of surface hydrocarbons. Oxymethylene oligomers can decompose along two competing routes to form formaldehyde or carbon and CO2. The addition of carbon dioxide to the feed gas mixture after the catalyst enters the stationary mode leads to a significant increase in its formaldehyde yield. It is obvious that the route with the formation of carbon dioxide is associated with the target reaction of formaldehyde production, where the catalytic reaction maintains a certain concentration of active centers. Thus, it can be assumed that carbon dioxide as a product of decomposition of surface oxymethylene compounds affects the rate of the catalytic reaction by maintaining a certain concentration of surface hydrocarbons, which are necessary as an element of the active catalytic center. For citation: Morozov L.N., Vorobyov A.S., Kunin A.V., Egorov N.A., Timoshin E.S. Effect of the feed gas mixture composition at methanol dehydrogenation to formaldehyde on supported oxide catalysts. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 7. P. 88-95. DOI: 10.6060/ivkkt.20246707.7003.