The impact of humic-based soil modifiers (HSM) produced from peat and coal (“Torfogel” and “Uglegel” accordingly) on chemical properties, cellulolytic activity and productivity of model soil mixtures (artificial soils) was evaluated in a pot experiment. Soddy-podzolic cultivated soil of the Moscow region was used as a natural reference soil. It is shown that an increase in the proportion of both HSM from 3 to 15% in soil mixtures improved their main agrochemical indicators: content of NPK and humus reached high levels, comparable to and exceeding those for the reference soil. Significant differences occurred starting from 5% of “Uglegel” content in mixtures, and 7% of “Torfogel”. Soil treatment with HSM stimulated the biological activity of soil mixtures, as well as plant growth and development. All the above trends were much more pronounced when treated with "Uglegel" in comparison with "Torfogel". This fact could be due to organic matter genesis of peat- and coal-originated HSM. The results of the work can be used to create stable and productive artificial soils.

Zeolites of the structural type ZSM-5 were synthesized using a template, which was pentaerythritol (PER), carbamide (CA), or a deep eutectic solvent (DES) - a binary mixture of PER and CA. It is determined by IR spectroscopy and X-ray diffraction analysis that the nature of the templates used in the synthesis of zeolites affects the phase purity and the degree of crystallinity of the obtained samples. The textural and acidic properties of zeolites and Mo-containing catalysts prepared from them by dry mechanical mixing with nanoscale molybdenum powder have been studied. It is shown that the textural properties of zeolites depend on the template nature. The use of CA promoted obtaining the zeolite with maximal specific surface area and pore volume. The strength of the acid centres of unmodified samples, depending on the structure-forming additive, decreases in the series: DES > CA > PER, and the concentration of acid centres of both types, on the contrary, decreases for zeolites in the series: PER > CA > DES. The catalytic activity of synthesized zeolites has been studied in the processes of non-oxidative methane conversion and refining of the straight-run gasoline fraction of oil. The dependence of the activity and stability of samples on their physicochemical properties caused by the template nature is determined. It has been shown that zeolite synthesized using DES and the 4.0%Mo/ZSM-5 catalyst obtained on its basis exhibit higher activity and stability in the processes of non-oxidative methane conversion into aromatic hydrocarbons and in upgrading the straight-run gasoline fraction of oil, in comparison with zeolite-based catalysts obtained using PER or CA.

The authors’ data (2000–2022) on synthesis methods, reactivity, and applied aspects of aryl- and hetarylacetylenes were summarized. The specificity of alkynylarenes (hetarenes) associated with the activation of the triple bond by acceptor groups was pointed out. Particular attention was paid to fundamentally important new reactions of heterocyclization and complete soft cleavage of the triple bond. The prospects for the use of alkynylarenes and -hetarenes and products of their modification were considered. The results of screening of the synthesized compounds were presented.

The effect of the method for the introduction of zirconium in the 4Mo/ZSM-5 catalyst and of its amount on the physicochemical and catalytic properties of the catalyst during the nonoxidative conversion of methane into aromatic hydrocarbons (benzene and naphthalene) has been studied. The catalyst was modified with zirconium by impregnation and solid phase mixing. The resulting zeolite catalysts were studied by IR spectroscopy, X-ray diffraction analysis, low-temperature nitrogen adsorption, temperature-programmed ammonia desorption, scanning and transmission electron microscopy, and simultaneous thermal analysis. With an increase in the zirconium concentration introduced in the 4Mo/ZSM-5 catalyst, the strength and concentration of its strong acid sites that are responsible for methane aromatization decrease regardless of the method of modification. The particle size and morphology of the catalyst, the distribution of Mo and Zr in them, and the presence of coke deposits on their surface were determined by scanning and transmission electron microscopy. The catalytic tests and subsequent thermal analysis of the samples showed that the addition of zirconium to the 4Mo/ZSM-5 catalyst leads not only to an increase in its catalytic activity, but also to operational stability due to the lower rate of coke formation. It was established that 4Mo/ZSM-5 modified with 1 wt % Zr by solid-phase synthesis is the most effective catalyst in methane dehydroaromatization (DHA).

We studied the effect of the nature of the structure-forming additive on the physicochemical and catalytic properties of the synthesized zeolites and catalysts prepared on their basis during the nonoxidative conversion of methane to aromatic hydrocarbons. Zeolites were synthesized by hydrothermal crystallization from alkaline alumosilica gels using hexamethylenediamine (HMDA) and ammonium bicarbonate (ABC) as templates. To create a mesoporous structure in zeolites, grade P354 carbon black was added to the reaction mixtures during synthesis. The synthesized zeolites were studied by IR spectroscopy, X-ray diffraction analysis, low-temperature nitrogen adsorption, scanning electron microscopy, and temperature-programmed desorption of ammonia. The catalytic properties of the samples were studied during the nonoxidative conversion of methane to aromatic compounds. All the synthesized samples are ZSM-5 zeolites; the addition of carbon black during their synthesis slightly affects their textural properties, increasing the volume of mesopores. The modification of zeolites with molybdenum results in a lower specific surface area and porosity. Zeolites obtained using HMDA are characterized by greater strength and a lower concentration of high-temperature acid sites compared to samples synthesized with ABC. The addition of molybdenum to zeolites lowers the strength and concentration of both types of acid sites. Mo-containing catalysts obtained from zeolites with a micro-mesoporous structure show higher activity and stability in the reaction of methane dehydroaromatization compared to microporous systems.

Исследовано влияние способа и количества циркония, введенного в катализатор 4Mo/ZSM-5, на его физико-химические и каталитические свойства в процессе неокислительной конверсии метана в ароматические углеводороды (бензол и нафталин). Катализатор был модифицирован цирконием методами пропитки и твердофазного смешения. Полученные цеолитные катализаторы исследованы методами ИК-спектроскопии, рентгенофазового анализа, низкотемпературной адсорбции азота, термопрограммируемой десорбции аммиака, сканирующей и просвечивающей электронной микроскопии, синхронного термического анализа. С повышением концентрации вводимого в катализатор 4Mo/ZSM-5 циркония снижается преимущественно сила и концентрация его сильных кислотных центров, отвечающих за процесс ароматизации метана, независимо от способа модифицирования. Методами сканирующей и просвечивающей электронной микроскопии установлена морфология и размер частиц катализаторов, распределение в них Мо и Zr, а также наличие на их поверхности коксовых отложений. Каталитические испытания и последующий термический анализ образцов показали, что добавка циркония к катализатору 4Mo/ZSM-5 приводит не только к увеличению его каталитической активности, но и стабильности работы за счет снижения скорости коксообразования. Установлено, что наиболее эффективным в процессе дегидроароматизации метана является катализатор 4Mo/ZSM-5, модифицированный 1 мас. % Zr-методом твердофазного синтеза.

The influence of the method of forming a secondary mesoporous structure in zeolites of the ZSM-5 type on the physicochemical and catalytic properties during the non-oxidative conversion of methane into aromatic hydrocarbons (benzene and naphthalene) of 4%Mo/ZSM-5 catalysts prepared on their basis was investigated. Catalysts of 4%Mo/ZSM-5 were obtained using granular zeolite without the use of a binder with a micro-mesoporous structure, zeolite treated with an aqueous solution of citric acid, and zeolite synthesized with the addition of carbon black. The obtained zeolite catalysts were studied by IR spectroscopy, X-ray diffraction analysis, low-temperature nitrogen adsorption, thermoprogrammable desorption of ammonia, high-resolution transmission electron microscopy. It is shown that the modification of zeolites with a micro-mesoporous structure by molybdenum, regardless of the method of their synthesis, leads to a decrease mainly strength and concentration of strong acid centers responsible for the process of methane aromatization. The strongest decrease in the content of strong acid centers is observed for zeolite treated with citric acid, which is associated with the dealuminization of zeolite. The study of textural characteristics showed that zeolites ZSM-5mmm and ZSM-5mmm/CA have the largest volume of mesopores than zeolite synthesized with carbon black. The morphology, particle size and the distribution of particles of the catalysts were determined by high-resolution transmission electron microscopy. Catalytic tests of the samples showed that the creation of an additional mesoporous structure in zeolites of the ZSM-5 type leads not only to an increase in the activity of 4%Mo/ZSM-5 catalysts obtained on their basis, but also to the stability of their operation. It has been found that the most effective in the process of methane dehydroaromatization is a 4%Mo/ZSM-5mmm catalyst treated with 0.3 N citric acid solution.

The influence of polyelectrolyte-based soil conditioners on the qualitative and quantitative composition of soil organic matter (SOM) was studied for two soils: sandy Dystric Arenosol (Aric) with 1% of C and silt loamy Abruptic Luvisol (Siltic, Cutanic) with 2% of C. The investigated polymer formulations included a synthetic polycation poly(diallyldimethylammonium chloride) (PDADMAC), a humic-based polyanion (commercial humic product Lignohumate, LH), and an interpolyelectrolyte complex (IPEC) prepared from PDADMAC and LH. In laboratory experiments, soils were treated with polymers and the composition of SOM was analyzed and compared with the control. The effect of polyelectrolytes on the molecular weight distribution and amphiphilic properties of SOM was evaluated using low-pressure size-exclusion chromatography and reversed-phase hydrophobic interaction chromatography. It was shown that the effect of polyelectrolytes differs depending both on the chemical nature and composition of polymers’ functional groups and on the soil properties. Polyanionic LH promoted mobilization of labile humic fractions, whereas polycationic PDADMAC was adsorbed in non-labile fractions. Positively charged IPEC occupied an intermediate position increasing the yield of mobile fractions only in sandy soil. The weighted average molecular weight of SOM slightly decreased with the application of all the polymers. The impact of IPEC on the distribution of hydrophobic and hydrophilic fractions depended on the native humus properties. In clay loam, it increased the proportion of the hydrophilic fraction, whereas in sandy soil the proportion of hydrophobic fractions was higher. Soil organic matter in the sandy low-humus soil provided more distinct effects of polymer application. In contrast, in a more humified loamy soil, polymers were immobilized by binding with the soil organomineral matrix and their effect on the SOM was weak.

The state-of-the art in the catalytic conversion of natural gas containing methane as the main component to valuable chemicals and fuels is reviewed. Methane conversion processes are of considerable importance to society; like oil, they are sources of energy, fuels, and chemicals. Direct and indirect means of methane conversion are discussed. Direct methane conversion processes are commonly thought of as the Holy Grail of modern research, since the methane molecule is extremely stable. Ways of producing synthesis gas, methanol, ethylene, formaldehyde, benzene, and other compounds are considered. The main emphasis is on processes of direct methane conversion (methane dehydroaromatization). Catalysts and the conditions for their synthesis are described, the state of active sites is studied, and a mechanism of methane dehydroaromatization is proposed. The reasons for catalyst deactivation and means of catalyst regeneration mechanism are described. The review helps summarize recent advances in heterogeneous catalysis in the field of natural gas conversion.

The review examines the current state of the catalytic conversion of natural gas into valuable chemical products and fuel. The main component of natural gas is methane. Methane conversion processes are of great importance for society because natural gas, along with oil, supplies us with energy, fuel and chemical products. Direct and indirect methods of methane conversion are considered. Direct conversion of methane is often viewed as the holy grail of modern research, since methane molecules are very stable. The review considers the methods of obtaining such compounds as synthesis gas, methanol, ethylene, formaldehyde, benzene, etc. The greatest emphasis is placed on the direct processes of methane conversion, namely on the dehydroaromatization of methane. The catalysts and the conditions for their preparation are considered, the state of active centers is studied, and the mechanism of methane dehydroaromatization is proposed. The reasons for deactivation of the catalysts and methods of their regeneration are also described. This review will help to summarize the latest known achievements in the field of heterogeneous catalysis for natural gas processing.

The physicochemical and catalytic properties of Mo/ZSM-5 catalysts for methane dehydroaromatization prepared using different (NH4- and H-) zeolite forms and nanosized Mo powder are studied. It is shown that the properties of the samples under study depend on the initial form of the zeolite used for their preparation. According to the data of electron microscopy and EDS analysis, the morphology and elemental composition of particles in the Mo/H-ZSM-5 and Mo/NH4-ZSM-5 samples are practically similar, and molybdenum is stabilized in the zeolite matrix in the form of the aggregates of atoms. The distribution profiles of silicon and molybdenum in the catalysts indicate that a more uniform distribution of molybdenum in the zeolite is observed for the Mo/NH4-ZSM-5 sample. Changes in molybdenum localization after methane dehydroaromatization were revealed. Molybdenum migration to the zeolite surface was observed, with the formation of MoCx particles up to 100 nm in size, coated with a carbon layer about 3 nm thick. It was established by means of the thermal desorption of ammonia that the concentration of strong acid sites in the catalyst prepared using the hydrogen form of the zeolite was lower than that for the catalyst prepared on the basis of the ammonium form of the zeolite. This difference in the acidic characteristics of the obtained Mo/ZSM-5 catalysts depends on the conditions of their preparation. The number of thermal treatments increased in the course of catalyst preparation using the hydrogen form of the zeolite, which resulted in the partial destruction of the zeolite crystal lattice with the formation of the Al-2(MoO4)(3) phase. Studies of the catalytic properties of the samples showed that the Mo/ZSM-5 catalyst prepared on the basis of ammonium zeolite exhibited the highest activity in the course of the nonoxidative conversion of methane to aromatic hydrocarbons.

Nonoxidative conversion of methane to aromatic hydrocarbons on granulatedМо/ZSM-5 catalysts was studied. The catalysts prepared using zeolites with thehierarchic pore system surpass in activity the catalysts prepared by thetraditional method, mixing of powdered Н-ZSM-5 with pseudoboehmite, followed bygranulation and calcination. The textural characteristics of the granulatedzeolites and of Mo-containing catalysts based on them were studied. The catalystsamples contain micro-, meso-, and macropores, but the pore formation pattern inthe granulated catalysts with the hierarchic pore system and in the catalystscontaining 30% binder is different.

The effect of cationic polyelectrolyte poly(diallyldimethylammonium chloride), anionic polyelectrolyte potassium lignohumate, and their interpolyelectrolyte complex on the aggregate composition and phytotoxicity of constructozem, an artificially constructed soil, is investigated. The original constructozem is characterized by a wide range of structural aggregates with a high proportion of large particles. Addition of the polycation to the constructozem completely destroys large aggregates, while addition of the polyanion has almost no effect on particle size distribution. The polycomplex sharply reduces the proportion of large particles and blocks the appearance of small particles, thereby significantly increasing the content of agronomically valuable aggregates in the constructozem and, at the same time, stimulating the growth and development of plants.

In this work, the introduction of modifying additives in the composition of catalysts is considered as an effective mode of improving functional characteristics of materials for two processes of methane conversion into valuable products – methane dehydroaromatization (DHA of CH4) into benzene and hydrogen and autothermal reforming of methane (ATR of CH4) into synthesis gas. The effect of type and content of promoters on the structural and electronic state of the active component as well as catalyst activity and stability against deactivation is discussed. For DHA of CH4 the operation mode of additives M = Ag, Ni, Fe in the composition of Mo-M/ZSM-5 catalysts was elucidated and correlated with the product yield and coke content. It was shown that when Ag serves as a promoter, the duration of the catalyst stable operation is enhanced due to a decrease in the rate of the coke formation. In the case of Ni and Fe additives, the Ni-Мо and Fe-Mo alloys are formed that retain the catalytic activity for a long time in spite of the carbon accumulation. For ATR of CH4, the influence of M = Pd, Pt, Re, Mo, Sn in the composition of Ni-M catalysts supported on La2O3 or Ce0.5Zr0.5O2/Al2O3 was elucidated. It was demonstrated that for Ni-M/La2O3 catalysts, Pd is a more efficient promoter that improves the reducibility of Ni cations and increases the content of active Nio centers. In the case of Ni-M/Ce0.5Zr0.5O2/Al2O3 samples, Re is considered the best promoter due to the formation of an alloy with anti-coking and anti-sintering properties. The use of catalysts with optimal promoter type and its content provides high efficiency of methane valorization processes.

The relevance of the investigation is caused by the need for rational use of natural hydrocarbon gases, containing methane as the main component. Currently, plenty of these gases are burned in flares at oil production sites, that does great damage to the environment in the oil-producing regions of our country. The most promising process that allows obtaining valuable chemical products is the non-oxidative methane conversion into aromatic hydrocarbons over zeolite catalysts modified with transition metal ions. The Mo/ZSM-5 catalysts have high activity in this process. These catalysts are obtained both by impregnation and solid-phase synthesis. Development of the method of preparation of Mo/ZSM-5 catalysts using binder is of great importance for the industrial technology of processing gaseous hydrocarbons. The aim of the work is to study the effect of concentration and method of introducing a binder on physicochemical and catalytic properties of the Mo/ZSM-5 catalyst in non-oxidative methane conversion. Methods of investigation: IR spectroscopy, low-temperature adsorption of nitrogen, temperature-programmed desorption of ammonia (TPD-NH3), gas chromatography. Results. The Mo-containing catalyst based on ZSM-5 zeolite and nanosized molybdenum powder was prepared via solid-phase synthesis. The authors have studied the effect of a binder on physicochemical properties and activity of the Mo/ZSM-5 catalyst in non-oxidative conversion of methane into aromatic hydrocarbons. It was ascertained that the addition of a binder to the Mo/ZSM-5 catalyst results in a change in its texture and acid characteristics. It is shown that the activity of the Mo-containing zeolite during the non-oxidative conversion of methane into aromatic hydrocarbons is determined by the concentration of the binder in the catalyst and does not depend on the method of its introduction.

The effect of the nature of the carbon template used in the synthesis of zeolites with a mesoporous pore system on their physicochemical properties is studied. It was revealed with the help of IR spectroscopy and X-ray phase analysis that the nature of the carbon material used in the synthesis of zeolites does not affect their crystallinity, which is 100 % for all zeolites. Investigation of the textural characteristics of the samples showed that the addition of carbon material to the reaction mixture during the synthesis of zeolite results in a decrease in the specific surface area and an increase in the volume of mesopores. The volume of micropores changes only slightly. The addition of carbon at the stage of zeolite synthesis leads to the formation of mesopores, the sizes of which are 3.5-20.0 nm in the case of the use of carbon black, and 3.3 8.6 nm in the case of nanoglobular carbon. The catalytic properties of Mo/ZSM-5 catalysts prepared on the basis of synthesised zeolites are studied, and the dependence of their activity and stability during the non-oxidative conversion of methane on the physicochemical properties of the zeolites used is shown. The formation of a mesoporous structure in the zeolite promotes a more uniform and dense distribution of Mo clusters with sizes not exceeding 1 nm in zeolite channels. It is shown that 4.0 % Mo/ZSM-5 catalysts based on zeolites with a mesoporous structure exhibit higher activity and stability in the non-oxidative conversion of methane to aromatic hydrocarbons than the catalysts based on zeolites with a microporous structure. The highest methane conversion is achieved over a 4.0 % Mo/ZSM-5 catalyst based on zeolite synthesised with carbon black.

The water-soluble components originated in coniferous litters desorb into solution the native organic substances from the solid phase of the eluvial horizons of podzols and podzolic soil. In podzols, the water-soluble organic matter ( WSOM ) extracted from litter and then passing through the E horizons are sorbed by the BFH horizons if their concentration in solution exceeds 35 mg C/L. The sorption ranges from tens to hundreds of milligrams of carbon per kilogram of the BFH horizon. The WSOM can be sorbed by the BT horizons of podzolic soil when the concentration of organic substances in the liquid phase is higher than in podzols. The model experiments with minerals show that kaolinite and illite interact with the soluble substances percolating from the litter and selectively extract more hydrophilic and less aromatic components with relatively low molecular weights. On the contrary, goethite interacts with the WSOM prevalently sorbing hydrophobic components, substances of phenolic nature, components enriched in aromatic carbon, and substances with molecular weights less than 7 kDa. The spectral characteristics of WSOM change after the sorption interaction with minerals: the fluorescence associated with the humus substances with the longest conjugation chain decreases or disappears, while new fluorophores containing fragments of phenolic and/or protein structures emerge. The presence of kaolinite and illite in the eluvial horizons and their interaction with WSOM most likely contribute to the transformation of WSOM composition and appearance of the properties maximally favorable for their sorption on iron hydroxides in the lower horizons.

The nonoxidative conversion of methane to aromatic hydrocarbons in the presence of a high-silica ZSM-5 zeolite modified with molybdenum and rhenium nanopowders has been studied. Data on the acid characteristics of the catalysts have been derived by temperature-programmed desorption of ammonia. The microstructure and composition of the Re/ZSM-5 and Re–Mo/ZSM-5 catalyst systems have been studied by transmission electron microscopy. It has been shown that modification of a Mo-containing zeolite with rhenium leads to an increase in the activity and stability of the catalyst in the methane dehydroaromatization reaction.