Membrane based separations are increasingly used due to advantages that these can offer. These are used to supplement or to replace energy intensive separation operations including distillation and evaporation. Most membrane separation operations operate at low to medium temperature and so these need less energy. Additionally, these operations are capable to miniaturize the equipment sizes. Reliability, robustness, possibility of scale up and cost effectiveness are few additional advantages that these can offer. This review discusses principle and application of membrane distillation in considerable detail, applied especially for less explored separation tasks, like those for organics and inorganics. Traditionally, MD was used for sea water desalination, brackish water treatment and also for brine treatment. Membrane distillation is also increasingly used for recovery of ethyl alcohol, from dilute solutions like those from fermentation broths. This review has considered separation of other volatile / nonvolatile, organic or inorganic chemicals using membrane distillation. This includes application to fruit juice, sugar, aroma, flavors, organics and inorganics and other miscellaneous compounds. Technical considerations like configuration of membrane module, application to the particular case, membrane materials, comparison with other membrane-based separation operations for the given separation, industrial applications and cost consideration are covered in this review. For citation: Jadhav H.R., Mahajan Y.S. A review on separation of organic and inorganic chemicals using membrane distillation. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2026. V. 69. N 4. P. 6-16. DOI: 10.6060/ivkkt.20266904.6878.
In this work, the time-varying rheological and structural-mechanical properties of a 3% solution of methylcellulose (MC-2000S), a polymer with a lower critical dissolution temperature, used as a basic component of thermotropic compounds developed by the Laboratory of Colloidal Chemistry of IPC SB RAS, used to EOR, was investigated. The measurements were carried out using a vibration viscometer "Rheokinetica" and a Viscotester iQ rheometer manufactured by Haake, equipped with a CC25 coaxial cylinder measuring system, when the sample was heated at a set speed in an oscillatory mode. The temperature was controlled by an external circulation thermostat ("Rheokinetica") and a Peltier element (Viscotester iQ) built into the rheometer. The dependence of viscosity on temperature at a constant value of the probe oscillation frequency (400 Hz) was recorded by vibrational viscometry, and in the oscillation mode, the dependence of the components of the elastic modulus and the modulus of complex viscosity on temperature at a given value of deformation (0.01) and frequency (1 Hz) was recorded. It was shown that in the temperature dependences of dynamic viscosity and complex viscosity modulus, after reaching the minimum viscosity, an increase is observed associated with the structuring of the sample, while mechanical destruction of the sample does not occur, as is the case when using rotational rheometry. It has also been established that the modulus of elasticity reaches a plateau after reaching a maximum, and the forming structure remains. The results obtained by various methods qualitatively coincide and organically complement each other-dynamic viscosity is important for the characterization of the initial low-viscosity solution, and its structural and mechanical (viscoelastic characteristics) are essential for the characterization of the gel, while the kinetics of the process can in principle be recorded by any of the non-destructive methods considered, taking into account their natural limitations in the viscosity range. The results of the work can be useful in the development of modern methods for increasing oil recovery using gel technologies for limiting water inflow and redistributing filtration flows into deposits during oil production.
The paper summarizes the literature data on an alternative method for producing automobile gasoline by joint processing on zeolite catalysts of the pentasyl type of mixed raw materials containing low-octane hydrocarbon fractions of various origins and alcohols-the & laquo;Metaforming & raquo; technology. The need to introduce unconventional methods for the production of high-octane gasoline is due to stricter environmental requirements for their quality and combustion products, as well as the projected shortage of fossil resources and the associated decrease in oil production with a simultaneous increase in the proportion of highly viscous and high-sulfur oils. The single-stage & laquo;Metaforming & raquo; technology makes it possible to produce gasoline of the required quality with lower capital and energy costs compared to traditional industrial technologies. The use of alcohols expands the possible raw material resources of fuels, especially in the case of their synthesis from renewable non-food raw materials, agricultural and household waste. The use of zeolite catalysts that do not contain precious metals, are not sensitive to the presence of sulfur and nitrogenous compounds in the composition of petroleum raw materials and do not require the presence of hydrogen-containing gas in the reaction zone, have a porous hierarchical structure, high thermal and hydrothermal stability, increases the yield of commercial gasoline and increases the duration of the interregeneration period of the catalysts. Currently, there are several types of & laquo;Metaforming & raquo; technology developed by domestic and foreign companies, but this technology has no industrial application. Due to the relatively simple technological scheme of production and the possibility of varying the hardware design and technological parameters of the process, hydrotreating or reforming plants operating at refineries can also be reconstructed for the & laquo;Metaforming & raquo; technology.
With light crude oil reserves declining, the development of effective methods for processing high-sulfur petroleum residues is becoming increasingly important. One promising method is the processing of tars in the presence of initiating additives. This paper presents the results of a study of the composition of the cracking products of vacuum residue from the Omsk Oil Refinery in the presence of solid-phase additives: calcium carbonate and acetate. Thermal processing of a vacuum residue mixture with varying amounts of solid-phase additives was carried out at 500 degrees C for 45 min. The main patterns of changes in the process material balance and the component composition of liquid cracking products depending on the additive amount were established. It was shown that the use of calcium carbonate and acetate in small quantities helps reduce the yield of solid cracking products. Gas-liquid chromatography was used to study the fractional composition of the products and the distribution of thiophene derivatives among fractions. It was found that the use of initiating additives increases the distillate fractions in liquid products by 1,5 times, compared to thermal cracking of vacuum residue. The fractional composition of the products and the distribution of thiophene derivatives among the fractions were studied using gas-liquid chromatography. It has been shown that the degree of sulfur removal from liquid products during thermal cracking of vacuum residue is insignificant. Derivatives of thiophene, benzo-, and dibenzothiophene are intensively formed and accumulate, which degrades the quality of the resulting distillate fractions. Some of the main sources of the formed thiophene homologues are resins and asphaltenes, as well as high-molecular sulfur-containing components of oils. The use of calcium carbonate and acetate additives helps to reduce the sulfur content in the liquid cracking products by almost 60% relative.
Molecularly imprinted polymers (MIPs) are used in the extraction, separation, and concentration of substances, as well as in chromatography and sensorics. A distinctive feature of these polymeric materials is their ability to recognize target molecules. Therefore, studying the sorption properties of MIPs is a pressing issue. Among the wide variety of polymeric sorbents, polyimides are particularly interesting. In this study, a mixture of 4,4'-diaminodiphenyl oxide and 1,2,4,5-benzenetetracarboxylic acid monomers was used to synthesize MIPs, using sodium dodecyl sulfate (SDS) E487 as a template. The prepolymerization mixture was thermally imidized, after which the resulting MIP was used to study its sorption capacity. The sodium dodecyl sulfate content in the solution was monitored conductometrically. The sorption experiments showed that sorption equilibrium was reached within 40 minutes. Sorption isotherms of anionic surfactant (E487) by molecularly imprinted polymers (MIPs) and non-imprinted polymers (NPs), respectively, were obtained. The following parameters were determined: recovery rate (R) (32.6% for MIPs; 13.5% for NPs), distribution coefficient (D) (0.483 dm(3)/g for MIPs; 0.143 dm(3)/g for NPs), and imprinting factor (IF) (3.4 for MIPs and 0.8 for NPs). It was experimentally established that polyimide-based MIPs exhibit higher sorption capacity than non-imprinted polymers. This is largely due to the presence of specific recognition sites in MIPs. The results of the work confirm the effectiveness of molecularly imprinted polymers in the sorption process of surfactant determination, which makes these polymers promising and relevant for practical application.
This work is devoted to the search for new massive nanodisperse catalytic systems based on molybdenum disulfide (MoS2) produced by a direct solid-phase method using a cryogenic approach. Single-component nanoscale powders (NP) of molybdenum disulfide were prepared under cryogenic conditions (77 K) in various gaseous media. Two-component composites based on molybdenum disulfide in combination with gas-phase nanopowders of cobalt (Co) and nickel (Ni), both with and without catalytic promoters, have been studied, when a pyrocarbon shell is present on the surface of NP Co. To obtain aAnew series of samples, mono-molybdenum disulfide of a layered structure was subjected to fine grinding in cryogenic media of various chemical compositions in combination with or without gas-phase NP Co and Ni. Dispersion, porosity, and catalytic activity in the hydrodesulfurization reactions of dibenzothiophene (DBT), as well as diesel fractions (DF), were determined for cryo-NP samples. The hydrogenation ability of the tested catalyst samples was evaluated. It was shown that using the cryogenic approach makes it possible to obtain new cryocatalysts with a high level of hydrodesulfurization ability of both model S-compounds and components of native raw materials. Possible relationships between the specific characteristics that were determined during the studies of the prepared cryo-samples and their catalytic activity were discussed. It was found that the addition of gas-phase NP in a pyrocarbon shell to MoS2 greatly reduces the catalytic activity of a two-component catalyst. It has been shown that cryo-catalysts based on mono-molybdenum disulfide of a layered structure with a micro-and mesoporous structure are characterized by high activity and stability in the hydrodesulfurization reactions of DBT and diesel oil fractions.
The study of two West Siberian fields crude oils (SK and VK) with a set of physico-chemical methods was conducted to determine the structural-group composition influence on their water-in-oil emulsions with distilled water. Oils, aromatic compounds, resins and asphaltenes were extracted, and their structural-group compositions were compared. Water-in-oil emulsions were formed with SK and VK crude oils as a continuous phase and distilled water as a dispersed one (30 wt.%). Microstructures of emulsions were investigated via the optical microscopy method. It was found that although both emulsions are similar in the water droplets mean diameters, the mean spherical particle surface area, and the sedimentation rate, the SK emulsions were characterized with a less stability. The rheological parameters of crude oils and their emulsions were studied and compared. Also pseudoplasticity coefficient was calculated for all chemical systems under study. According to results of & laquo;bottle test & raquo; method conducted for 48 h at 20 and 50 degrees C, VK oil emulsions were more stable despite the lower content of asphaltenes and the smaller asphaltenes/resins ratio. Its emulsion does not break down under these experimental conditions, while about 50 vol.% of distilled water was extracted from the SK emulsion. According to results of FTIR-spectroscopy and potentiometric titration, the VK oil is characterized with the higher oxygen-containing components and acidic groups content. Components containing them can add to emulsions stability and therefore compensate the less asphaltenes content, which is a probable scenario in the SK and VK crude oils case.
Aminophenol derivatives have attracted increasing attention in recent years due to their wide-ranging biological potential and synthetic versatility. A large number of compounds belonging to this class have been synthesized and investigated, primarily because of their diverse biological benefits, which include notable antimicrobial, anticancer, and antioxidant activities. Beyond their intrinsic bioactivity, aminophenols are also recognized as important precursors for the construction of bioactive heterocyclic frameworks, thereby extending their value in medicinal chemistry and drug discovery. Advances in modern organic synthesis have enabled the preparation of aminophenol derivatives in excellent yields, often exceeding 90%, through a variety of strategies. Among the most widely employed are one-pot procedures that achieve direct substitution of the phenolic hydroxyl group in hydroquinone with amino functionalities, as well as classical reductive transformations of nitrophenol derivatives using specific reducing agents. In parallel, several alternative synthetic methodologies have been reported, offering shorter synthetic sequences, low-cost reagents, and simple experimental operations, which collectively facilitate accessibility and cost reduction across different laboratories. While some limitations remain with respect to their anticancer and antimicrobial efficacy, their antioxidant properties are particularly remarkable. Nearly all aminophenol derivatives display strong radical-scavenging activity, often comparable to or surpassing standard antioxidants such as ascorbic acid (AA) and butylated hydroxyanisole (BHA). Taken together, these findings underscore the significance of aminophenol derivatives as both promising therapeutic agents and versatile intermediates in synthetic and medicinal chemistry. For citation: Ngo Lan Anh, Nguyen Van Dat A review on synthesis of aminophenol derivatives and their biological activities evaluation. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2026. V. 69. N 5. P. 6-22. DOI: 10.6060/ivkkt.20266905.6756.
The paper presents the results of studying the effect of fibrous basalt on the physical and mechanical properties of thermoplastic elastomers based on polypropylene and styrene-butadiene elastomer (SKS). The elastomer content in the mixture with polypropylene varied within 10-70 wt%. The pattern of changes in the tensile strength and yield strength depending on the elastomer content was determined. It was found that at 30 wt% of elastomer, phase inversion occurs with the formation of a thermoplastic elastomer. The amount of fibrous basalt in the composite varied within 5.0-30 wt%. The effect of fibrous basalt content on the pattern of changes in the tensile strength for composites based on PP+30 wt.% of SKS and PP+40 wt.% of SKS is shown. The effect of sulfur and dicumyl peroxide on the vulcanization process of composites with different contents of fibrous basalt was studied. The content of dicumyl peroxide varied within the range of 0.25 - 0.5 wt.%. Optimum concentrations of mixture components have been determined, at which the highest strength indicators are achieved, depending on the content of filler and vulcanizing agents. The temperature regions of the phase transition were determined of the first kind of the considered composites depending on the content of fibrous filler and vulcanizing agents. It is shown that with an increase in the filler content, with subsequent vulcanization of the mixture, the softening temperature of the composites increases sharply. The thermophysical characteristics of composites based on thermoplastic elastomers were determined using the derivatography method. It has been shown that the introduction of fibrous basalt and sulfur vulcanization practically does not lead to a significant change in the melting temperature of composite materials and the degree of their crystallinity. From the data obtained, it was assumed that sulfur vulcanization occurs mainly in the amorphous region, i.e. in the mass of the elastomer component.
A combination of methods, including scanning electron microscopy, X-ray diffraction analysis, Fourier transform infrared spectroscopy, and structural group analysis was used to trace the evolution of the molecular and supramolecular organization of asphaltenes in light and heavy crude oils during their thermal conversion in supercritical n-hexane. It has been shown that thermolysis of asphaltense under supercritical conditions is accompanied by the disintegration of the initial nanoaggregate and formation of smaller particles. Moreover, the asphaltenes of light crude oil undergo more extensive degradation. It was found out that the cracking of saturated fragments and the condensation of aromatic nuclei in the molecules of the resulted high-molecular components under conversion conditions occur simultaneously. This is evidenced by an increase in the size of quasi-crystallites in the structure of 'secondary' asphaltenes, an increase in the degree of aromaticity, and a decrease in the content of naphthenic rings in the structure of 'secondary' asphaltenes and the resulted resins. The resulted oil components are enriched in long-chain n-alkanes and depleted in heteroatoms. They are characterized by similar molecular composition. The compounds identified in the oils are n-alkanes, alpha-olefins, naphthenes, mono-and polycyclic aromatic hydrocarbons, including naphthene-aromatic and sulfur-containing structures. It was found out that oil components resulted from the conversion of light crude oil asphaltenes contain alkyl derivatives of policyclic aromatic hydrocarbons of higher molecular weight than those obtained by converting heavy crude asphaltenes. The data obtained indicate similarities in the thermal transformations of light and heavy crude oil asphaltenes. Differences in the macromolecular architecture of the original asphaltenes manifest themselves in the composition of the degradation products. This finding mayAbe useful for molecular characterization of the oils and prediction of the behavior of their resin-asphaltene components during thermal processing.
This paper presents the results of a study on the deactivation dynamics of a P-containing zeolite catalyst during the conversion of propane to olefinic hydrocarbons. Catalytic dehydrogenation of light alkanes enables the production of olefins and hydrogen with high selectivity. However, the dehydrogenation reaction of light alkanes has a number of characteristics and limitations that determine the range of catalysts that can be used. Selecting the most suitable catalyst for the dehydrogenation process is an important factor, significantly affecting the selectivity of the target product-lower olefins. Zeolites, with their microporous structure and specific textural and acidic properties, are widely used as catalysts in various petrochemical processes, including the production of olefinic hydrocarbons. One of the challenges associated with the use of zeolite catalysts is the intense formation of coke during hydrocarbon conversion, which reduces their activity by blocking acid sites and restricting the access of the starting reactants. Zeolite catalysts modified with phosphorus have recently attracted increased attention from researchers due to their relatively low cost, increased selectivity, and operational stability. A P-containing zeolite catalyst has been shown to exhibit high selectivity and operational stability in the production of lower olefins from propane. The selectivity for olefin hydrocarbon formation after 24 h of catalyst operation is at least 70%, with a propane conversion of 44%. The nature and amount of carbon deposits formed on the studied catalyst during the process were determined. It was shown that the coke formed on the surface of the P-containing zeolite catalyst is characterized by a relatively low degree of polymerization/polycondensation and can be completely removed by oxidative regeneration.
Processing of heavy oils to obtain less viscous "synthetic oil" enriched with light fractions is a pressing issue. In this paper, catalytic cracking and hydroprocessing of heavy oil in the presence of catalysts based on tungsten carbide powder and nichrome are considered. It was found that catalytic cracking additionally forms 9.8 % of light fractions compared to thermal cracking and 30.6 %wt compared to the original oil, accelerating the formation of by-products. The destruction of resinous-asphaltene components is more than 60%rel It was revealed that during hydroprocessing of heavy oil in the presence of NiCrWC with an increase in hydrogen pressure from 0.1 to 3.0 MPa, a greater number of light fractions are formed, reaching 61.8%wt, and a lower yield of by-products. After hydroprocessing, resin and asphaltene molecules become more aromatized and condensed (low H/C and high fa). It is noted that at a pressure of 1.0 MPa, desulfurization reactions predominate, sulfur removal is 65%rel. Using X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy, it was found that surface oxides of nickel and chromium form sulfides when interacting with sulfur-containing components of heavy oil. Using the X-ray photoelectron spectroscopy method, it was found that the carbide form of tungsten is stabilized by surface oxygen, which is removed during hydroprocessing.
The article is devoted to the study of the processes of sorption and desorption of copper ions on aAnew carbon-containing wood-chitosan cationite. A technique for obtaining aAnew natural sorbent was described, and equilibrium under static conditions was investigated. The data obtained were processed within the framework of the Langmuir, Freundlich and Temkin models. It was shown, that Langmuir-Amodel describe sorption of copper ions on the cationite. The experimental studies of processes of ion-exchange sorption and desorption of copper ions on the wood-chitosan carbon-containing cationite in a laboratory apparatus were carried out. The ion exchange unit contains anAion exchange filter, inside which upper and lower drainage and distribution devices are installed, and there is a layer of ion exchanger particles with a density lower than the density of the purified water, and a layer of inert material particles with a density higher than the density of the purified water. During the research, output curves were obtained, on the basis of which the parameters of the ion exchange process were calculated: its relative speed, dynamic exchange capacity of the cation exchanger, degree of regeneration of the cation exchanger, specific consumption of the regeneration solution, internal diffusion coefficients, etc. Cationite and ion exchange apparatus are recommended for cleaning solutions and wastewater from copper (II) ions.
Due to declining reserves of light crude oils, the inclusion of heavy hydrocarbon feedstocks (atmospheric and vacuum residues) in the processing of crude oils is becoming increasingly important. Processing such feedstocks requires the development of new and effective methods for the destruction of high-molecular components (resins, asphaltenes), which will yield distillate fractions and reduce the formation of solid coke-like products. One promising method is the conversion of heavy hydrocarbon feedstocks in a supercritical water environment. This paper presents the results of a comparative analysis of the products of the thermal treatment of three samples of petroleum residues (fuel oils) in a supercritical water environment and in the presence of iron(III) acetylacetonate. Thermal treatment was carried out in an autoclave reactor at a temperature of 450 degrees C for 60 min. The pressure in the experiments with water was up to 47 MPa. Characteristic features of changes in the substance and fractional compositions of the cracking products were demonstrated. Thermolysis in supercritical water demonstrated that petroleum residues with significantly different compositions and physicochemical properties respond differently to hydrothermal treatment. For two of the three residues, a positive effect on conversion was demonstrated, with a decrease in the yield of solid products and an increase in the yield of target products (gasoline and diesel fractions). Using a kinetic model of the cracking process, changes in the rate constants of thermal transformation reactions of petroleum residue components were estimated. It was shown that during thermal cracking, the highest constants are those for condensation reactions along the resin-to-asphaltenes and then coke pathways. Thermolysis in a supercritical water environment facilitates a change in the direction of the processes, as evidenced by an increase in the constants of the degradation reactions and a decrease in those of the condensation reactions.
This paper presents the results of an experimental study of the efficiency of using oil-displacing acid compositions developed at the Institute of Petroleum Chemistry SB RAS (GBK, GBK-F, MIKA-1) as destructors of cross-linked guar gels used in hydraulic fracturing. Gel degradation by various compositions (GBK, GBK-F, MIKA-1), their liquid commercial forms (LCF), and their working solutions was experimentally studied in a wide range of gel-to-degrader ratios, both without stirring and with vigorous stirring. Visual observations, measurements of the rheological characteristics, and physicochemical properties of the gel-to-degrader systems were conducted under dynamic and static degradation conditions. The studied oil-displacing acid compositions GBK, GBK-F, and MIKA-1 demonstrated their effectiveness as cross-linked guar gel degraders. It was found that the working solution and the LCF of the GBK-F composition are the most effective cross-linked guar gel degraders. They ensure complete gel degradation even without stirring. The compositions GBK, MIKA-1, and GBK+AlCl3 are less effective, but can also be used as cross-linked guar gel degraders. Intensive mixing accelerates the process but does not change the ranking of the compositions by effectiveness as cross-linked guar gel destructors. The study demonstrates the potential for using the studied multifunctional acid compositions, which combine the properties of a destructor and an oil-displacing agent, in hydraulic fracturing technology. The obtained results can be used to select targets for industrial application of the compositions-individual wells, sections, formations, and fields-and to predict the technical and economic impact.
The chemical interaction of an aqueous solution of polyvinyl alcohol (PVA) with boric acid (BA) in slightly acidic and alkaline media was studied. It was shown that at a temperature of 5 degrees C, with increasing NaOH concentration, gel formation occurs within 5 to 15 min. In a slightly acidic medium at the same temperature, gelation proceeds at a slower rate, with the viscosity of the system increasing within 24 h. A comparative analysis of the properties of samples obtained as a result of chemical interaction without freezing (gels) and after a freeze-thaw cycle (cryogels) was conducted. It was shown that the mass loss of gel and cryogel samples formed in a slightly acidic medium during storage in water is 10% and 5% of the initial mass, respectively. The mass loss of gel and cryogel samples obtained from an alkaline PVA solution is less than 2% of the initial mass. The elastic and thermal properties of the samples were studied. It was found that the elastic modulus of both the gel and cryogels obtained from an aqueous PVA solution in an alkaline medium was higher. The melting point of the gel obtained in a slightly acidic medium was approximately 10 degrees C lower than that of the gel obtained in an alkaline medium. After a freeze-thaw cycle, the melting point of both cryogels increased. Films were obtained from the structured systems (gels and cryogels) after drying. It was noted that the mechanical strength of the films was influenced by the pH of the initial polymer solution and the subsequent cryogenic treatment of the gel. The tensile strength of films obtained from a PVA solution cross-linked with BA in a slightly acidic medium without freezing was shown to be 45 MPa, while that of the cryogels was 58 MPa. Films obtained from gel or cryogel by cross-linking PVA macromolecules in an alkaline medium exhibit higher tensile strengths of 60 MPa and 95 MPa, respectively. Thus, by cross-linking macromolecules with boric acid in an alkaline PVA solution, it is possible to obtain waterproof materials with variable rheological and physicochemical properties, which can be used as impermeable barriers, for example, in the reclamation of man-made soils in the mining industry.
This review article discusses modern synthesis methods and applications of heteroaromatic porous polymer materials. Heteroaromatic polymers can be effectively used in the conversion of photoenergy in solar cells, the adsorption and storage of gases, the delivery and release of medicines, the removal of pollutants from water and other solvents, photocatalysis and catalysis, including metal-free catalysis. Most of the article is devoted to the use of crosslinked porous polymers containing heterocyclic fragments as carriers of heterogeneous catalysts. The interest in such carriers is due to their unique properties, the simplicity of synthesizing structures of a given morphology and composition, as well as the possibility of their functionalization. The introduction of heteroatoms into polymers can be carried out using monomers containing heteroatoms, as well as by including N/S/O-containing fragments in polymers. The most common building blocks include triazines, heterocyclic carbenes, porphyrin, carbazole, imidazole, phenanthroline, thiophene, furan, and other heterocyclic compounds. In this review, materials on synthesis methods using various types of monomers are considered. Crosslinked porous polymers have a high specific surface area, adjustable porosity, have high chemical and thermal stability, as well as good coordination ability and allow reliable fixation of metal nanoparticles in the polymer matrix, which makes them more resistant to deactivation in a wide range of reactions. The specific properties provided by heteroatoms make it possible to increase the adsorption efficiency and favorably affect the catalytic activity. For citation: Bakhvalova E.S., Nikoshvili L.Zh., Sulman M.G. Application of heteroaromatic porous polymers as catalyst supports. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2026. V. 69. N 5. P. 23-35. DOI: 10.6060/ivkkt.20266905.6953.
This study presents a comprehensive spectroscopic study of molybdenum(VI) isopolycompounds - representatives of an important class of polyoxometalates (POMs). These compounds, which possess structural diversity and a broad range of functional properties, serve as model objects for studying the formation and reactivity of metal oxide clusters. The aim of the study was to establish correlations between the composition, structural features, and spectral characteristics of the synthesized polyoxomolybdate compound using a combination of physicochemical analytical methods. The polyoxomolybdate compound was synthesized using a novel method using a mechanically activated precursor, hydrogen peroxide, and lactose as a reducing agent in an acidic medium (pH 1.12), which corresponds to the conditions for the formation of highly nuclear oxometalate clusters. The product was characterized using electronic spectroscopy, NMR spectroscopy on 95Mo and 17O nuclei, and IR spectroscopy. The electronic absorption spectrum revealed a broad band in the 700-950 nm range with a maximum at 860 nm, which is interpreted as intervalent charge transfer Mo(V)-> Mo(VI). The observed bathochromic shift of the maximum relative to the literature data (740-770 nm) may be associated with the formation of large nanoaggregates or with an increased degree of molybdenum reduction. NMR spectra of 95Mo revealed broad signals indicating the presence of molybdenum in various chemical environments within the polynuclear complex. In the NMR spectrum of 17O, along with the signal from water, low-intensity signals corresponding to oxygen atoms in the framework were detected. The IR spectrum of the sample contains characteristic absorption bands in the 900-400 cm-1 range, related to vibrations of Mo-O bonds, as well as a number of bands in the 1000-2000 cm-1 range and above 3000 cm-1, indicating the presence of organic components (carboxylic acids) included in the synthesized system. This study contributes to the development of spectral-structural databases for polyoxometalates and is relevant for the targeted synthesis and compositional control of such compounds.
This study focuses on the production of phytodistillates (hydrolates), a comprehensive analysis of their properties, and their role in modern cosmetology as valuable byproducts of plant-based raw materials processed without the use of chemical additives. Natural plant phytodistillates were obtained using steam distillation. These hydrolates were selected due to their wide range of beneficial properties: wormwood, peony, jasmine, and plantain. Studies were conducted to study their stability over time, demonstrating their suitability for all human skin types based on determination of the pH levels of the samples. The study focused on the antibacterial and fungicidal properties of the resulting phytodistillates. The antibacterial properties of wormwood phytodistillate were studied using highly sensitive bioluminescent bacterial test subjects, such as Aliivibrio fischeri and E-coli. The experimental results demonstrated that even at significant dilution, wormwood hydrosol effectively inhibited both bacterial growth and bioluminescence. Complete suppression of bacterial growth was observed at a two-fold dilution. Using IR spectroscopy, we determined the complex chemical composition of phytodistillates, including flavonoids, carotenoids, phytosterols, and other biologically active substances. Adding a preservative to the resulting hydrolates was shown to be ineffective at all stages of the study. Experiments demonstrated the superiority of wormwood phytodistillate over peony, jasmine, and plantain hydrolates. These results offer promise for further development of medicinal and cosmetic products based on wormwood hydrolate.
The paper presents the results of determining the products formed during the treatment of liquid benzene-ammonia solution systems in dielectric barrier discharge plasma under argon and air amospheres. The benzene-ammonia solution systems treated with dielectric barrier discharge were analyzed using gas chromatography and spectroscopy in the visible and ultraviolet regions. It was found that the treatment of a homogeneous benzene-ammonia solution emulsion stabilized with sodium oleate in argon with electric discharges allows one to obtain aniline and nitrobenzene with selectivities of 32.7 wt.% and 50.1 wt.%, respectively, at a benzene conversion of 1.3 wt.%, while an air atmosphere leads primarily to the formation of phenol. The processing of a heterogeneous benzene-ammonia solution mixture in a dielectric barrier discharge also allows to obtaine aniline and nitrobenzene, however, at a significantly lower benzene conversion of 0.1 wt.%. Treating benzene and ammonia solution supplied separately from different vessels results in both a relatively low benzene conversion (0.1 wt%) and a low aniline yield (6.3 wt% relative to the total product mass), while nitrobenzene was not detected. Quantitative results suggest the significant role of the homogeneity of benzene-ammonia solution systems and an inert gas atmosphere in the formation of aniline and nitrobenzene. The results of this study can be used in developing methods for producing amino-and nitro-containing derivatives of liquid hydrocarbons under plasma conditions, as well as for studying the effects of electrical discharges on liquid media, including colloidal systems.
