Home – Home – Jornals – Chemistry for Sustainable Development 2025 number 1

Developing the approach to the synthesis of polyfluorinated boron derivatives formulated as one precursor, a series of target products, tested previously using O-, N-, and C-nucleophiles, a series of potassium 4-arylthiotetrafluorophenyltrifluoroborates was obtained through the action of organylthiols in the presence of bases on potassium pentafluorophenyltrifluoroborate.

In the studies of the human habitat, similar organic substances are commonly determined summarily (group analysis). In the present work, a review of publications related to the years 2015-2023, dealing with the group analysis of hydrochemical objects and foodstuffs is presented. In both cases, a traditional and most widespread method of group analysis is the total index calculation, in spite of the metrological incorrectness of this method. The corresponding assays include measuring of generalized signals, construction of univariate calibration and rough estimation of the total content (c_Σ) of the analytes, calculated for a certain standard substance. The new group analysis instruments for hydrochemical objects are the inverted multivariate calibrations, and for antioxidant determination in foodstuffs - the interval estimates of c_Σ. These new group analysis variants lead to more correct results, however, they have not been studied in sufficient detail and are rarely used in actual practice. The application of multivariate calibrations is hindered by the labour-intensive construction of training sets, while the use of interval estimates is hindered by the intergroup signal selectivity, leading to excessively wide intervals. The trends in the development of group analysis and promising directions of future investigations are discussed.

The influence of polyisobutylene of grades P-30 and P-200 on the rheometric, physico-mechanical and dynamic properties of rubber used for manufacturing the products exposed to sea water has been investigated. The rubber compound included: butadiene-styrene DSSC-628B and chlorobutyl KhBK-139 rubbers, vulcanising agent (sulphur), vulcanisation accelerators (2,2'-dibenzthiazole disulphide, guanide F), vulcanisation activators (zinc white, stearic acid), antioxidant (N-phenyl-2-naphthylamine), softeners (rosin, petroleum bitumen, factis), fillers (trans-polynorbornene, carbons black (P 514, P 803), and natural chalk). As a result of the studies, it is established that with an increase in the content of polyisobutylenes from 5 to 20 phr a change in the physico-mechanical properties of rubber is observed (a decrease in tensile strength, hardness, and tear resistance), while the relative elongation at break and the dynamic properties of rubber increase. Moreover, with polyisobutylene content up to 15 phr, the physico-mechanical properties of rubber change within acceptable limits, but at 20 phr these properties deteriorate sharply. Vulcanisates containing polyisobutylenes P-30 and P-200 up to 15 phr exhibit smaller changes in physico-mechanical properties and mass after exposure to sea water. It has been determined that rubber containing 15 phr polyisobutylene P-200, due to its physico-mechanical, performance and dynamic properties, can be recommended for the manufacturing the products operating under exposure to sea water.

The influence of the structure of low molecular weight nitrogenous bases in heavy oil on the composition and aggregative stability of asphaltenes has been studied. The objects of investigation were asphaltenes of heavy oil from the Usinsk field, as well as asphaltenes of model petroleum systems with nitrogen content 1.0-3.0 wt%, obtained by mixing the original oil with quinoline and pyridine. IR spectroscopy and elemental analysis were used to determine the composition and structure of asphaltenes. The colloidal stability of asphaltenes was analysed by spectrophotometry. It is shown that the introduction of nitrogenous bases into heavy oil leads to a decrease in hydrogen content with an increase in the proportion of nitrogen, which points to the incorporation of pyridine and quinoline molecules into the supramolecular structure of asphaltenes. The main reason for the incorporation of nitrogenous bases into asphaltene aggregates is the p-stacking interactions of aromatic rings. The colloidal stability of asphaltenes, assessed as the time of sedimentation onset, is determined to increase by a factor of 1.5, with an increase in pyridine content, and the degree of sedimentation inhibition can reach 90 % with respect to asphaltenes in the original oil. On the contrary, the presence of quinoline in asphaltenes causes a several-fold decrease in the time of their aggregation onset, but it also promotes detention of a part of aggregates in the colloid state, which results in a decrease in the amount of precipitate in comparison with original oil.

The features of the behaviour of rare earth elements (REE) and strontium in hemihydrate and dihydrate processes of sulphuric acid processing of Khibiny apatite concentrate have been studied on the basis of investigation of the residues of aqueous leaching of phosphogypsum obtained under production conditions. It has been shown that the increased degree of REE ingress into phosphogypsum of the hemihydrate process, compared to phosphogypsum of the dihydrate process, is determined by the technological features of these processes: higher temperature and REE concentration in the liquid phase of the pulp of the hemihydrate process, compared to the liquid phase of the pulp of the dihydrate process. In contrast to existing ideas, it is theoretically justified and experimentally confirmed that a significant part of REE in phosphogypsum of the hemihydrate process is present in the form of rhabdophane. Rhabdophane was not found in phosphogypsum from the dihydrate process, and it is most likely that REE in phosphogypsum from the dihydrate process are isomorphically cocrystallised with gypsum. It has been established that strontium occurs partially in the form of celestine in phosphogypsum of both processes. It is shown for the first time that celestine, present in phosphogypsum of the dihydrate process, contains isomorphically cocrystallised REE. It has been suggested that isomorphically cocrystallised REE may be also present in celestine from phosphogypsum of the hemihydrate process. The influence of REE forms present in phosphogypsum on the possibility of its sulphuric acid leaching is discussed. The results obtained in the work are of high practical importance because sulphuric acid leaching is widely recommended for organising the industrial extraction of REE from phosphogypsum obtained during sulphuric acid processing of the Khibiny apatite concentrate.

The results of studies conducted at the Institute of Combustion Problems (Almaty, Kazakhstan) on the synthesis of nanocarbon materials and their application for environmental purposes are presented. The procedures have been developed for obtaining nanocarbon materials from rice husk and walnut shells (graphenes and activated carbon, respectively), the physicochemical properties of the synthesised materials and the possibility of their practical use are studied. Graphene investigation by infrared and Raman spectroscopy allowed us to analyse the surface functional groups and the structural features of the material composed of a mixture of amorphous carbon and graphene, the ratio between these components depending on synthesis method. With an increase in the amount of the alkaline agent, the content of graphene component in the structure of carbon material increases. The porous structure and morphology of carbonised materials from rice husk and walnut shells were characterised according to the data of scanning electron microscopy. Nanocarbon graphene structures and activated carbon synthesised from the waste plant materials have demonstrated good adsorption properties for sea water desalination and sorption of toxic gases.

The anthropogenic emission of greenhouse gases, mainly carbon dioxide (CO₂), is considered as one of the main causes of global climate change. The transport sector is one of the largest emitters of carbon dioxide (accounting for more than 20 % of all CO₂ emissions), therefore, reducing the carbon footprint of vehicles should be considered one of the main directions of technological decarbonisation. It is shown in the article that the CO₂ emissions of motor gasoline significantly depend on the component composition of commercial gasoline. Calculations of specific CO₂ emission from the combustion of high-octane components of motor gasoline, namely reformate and isomerisate, were carried out. It is shown that for reformate, the specific emission of CO₂ per 1 t of reformate and per unit energy released is higher by 6.0 and 13.4 %, respectively, than the values for isomerisate. It is shown that the main reason for large specific CO₂ emissions for reformate is the high content of aromatic hydrocarbons in it. Moreover, unlike for paraffinic hydrocarbons, the lower is the molecular weight of aromatic compounds, the higher are specific CO₂ emissions. The presented results can be used to implement the transition to the low-carbon model for the development of the transport sector by utilising more environmental-friendly kinds of fuel through modifying its composition. These approaches do not require changing the design of internal combustion engines or introducing new infrastructure, as in the case, for example, of using engines powered by pure hydrogen.

Steam and steam-air reforming of butanol allows obtaining synthesis gas that can be used as a feedstock in a number of chemical applications or as a fuel for solid oxide fuel cells. The efficiency of these reactions is largely determined by heat transfer. In the case of steam reforming of methane, which is an endothermic reaction, it is necessary to provide heat transfer from the reactor walls into the catalyst layer. During steam-air conversion, which is a thermoneutral or weakly exothermic reaction, local overheating occurs in the front layer, the thermal effect of which must be redistributed over the catalyst layer to compensate for the endothermic effect prevailing in the tail section. To increase heat transfer, structured catalysts based on heat-conducting substrates, namely metal meshes, are used in this work. Such catalysts are a complex composite material with a multi-level structure: structured metal substrate - structural oxide component - active oxide - nanoparticles of metals or alloys, which combines the functions of a heat exchanger, a flow distributor and the catalyst itself. This allows you to control heat and mass transfer, regulate gas-dynamic resistance in the reactor and optimise the amount of catalytic material. In this work, the results of the preparation and study of the physicochemical and catalytic properties of Pt, Rh, Pd, Ru, Ni-containing structured catalysts supported on a fechral (FeCrAl) mesh support are presented. The prepared structured catalysts were tested in the reactions of steam and autothermal conversion of n-butanol into synthesis gas. The highest activity in these reactions was shown by the rhodium structural catalyst. Short-term laboratory resource tests for 15 h did not reveal the presence of soot on the surface of the catalyst, and the composition of the reaction products was close to thermodynamic equilibrium. This catalyst can be recommended for use in reformers for steam and steam-air conversion of butanol-1 to produce synthesis gas.

The possibility of obtaining benzocaine succinamide under the conditions of mechanochemical reaction of succinic anhydride with benzocaine (a local anesthetic) is demonstrated. It has been established that mechanical treatment in a ball mill results in amorphisation of initial substances, promoting adsorption of succinic anhydride on the surface of drug crystals, which leads to the chemical interaction between initial components. An intensive development of solid-phase interaction was determined to proceed intensively during 10 days after the load was removed. The maximum transformation degree (~90 %) was detected for the mechanical treatment of an equimolar mixture of benzocaine and succinic anhydride, in the amount of 4 g, in a ball mill for ~2 h. With a decrease in the mixture mass or increase in the load applied, the maximum yield is achieved within a shorter time. The conversion degree was determined to decrease with an increase in the time of mechanical action in all cases. The detected feature can be related to the equilibrium amidation under the conditions of heating during the long-term action of the impact load.

High-temperature studies of the structure of a composite material with the composition La_0.6Sr_0.4Co_0.2Fe_0.8O_3-δ-Ce_0.8Sm_0.2O_2-δ (LSCF64-SDC) have been carried out, and the oxygen permeability of microtubular membranes based on it was investigated. The phase composition of LSCF64-SDC composite was analysed using in situ high-temperature X-ray diffraction. It has been determined that at 700 °C under vacuum conditions, a structural transition to the high-temperature cubic phase occurs in LSCF64 oxide. The dependence of the oxygen permeability of microtubular membranes based on LSCF64-SDC on the partial pressure of oxygen and temperature has been established. The effective activation energy of the oxygen transport process was calculated. The effect of the CO₂ atmosphere on the values of oxygen flows through the microtubular membranes based on LSCF64-SDC was studied.

Quantum chemical simulation of the adsorption of phenylethanol on a tetrahedral Au₂₀ cluster was carried out using the density functional theory, DFT/B3LYP/LANL2DZ. It has been shown that gold atoms located at the top of the cluster have the highest activity in the adsorption of alcohol. Possible reactions of phenylethanol on Au₂₀ cluster to form phenylacetaldehyde were studied. Based on the calculated thermodynamic and kinetic values, it is concluded that the transformation proceeds predominantly through the metal hydride mechanism.

The proportion of hard-to-recover oil reserves in the world and in Russia is constantly growing. The development of hard-to-recover reserves, including high-viscosity oil deposits, low-permeability reservoirs, and difficult production conditions, such as the Arctic, is becoming an increasingly important factor in maintaining high levels of oil production. For the effective development of hard-to-recover reserves, physicochemical and complex technologies for increasing oil recovery have been developed at the Institute of Petroleum Chemistry SB RAS on the principles of green chemistry, buffer self-regulating systems and the method of deep eutectic solvents (DESs) using the smart compositions of surfactants, coordinating solvents, and complex compounds. The compositions chemically evolve in the reservoir with the acquisition and long-term preservation of colloidal chemical properties that are optimal for oil displacement. Factors causing chemical evolution include thermobaric reservoir conditions, interaction with reservoir rock and reservoir fluids. The review presents the fundamental and applied aspects of the physicochemical and complex methods for increasing oil recovery, developed at the Institute of Petroleum Chemistry SB RAS, the results of laboratory studies, field tests and industrial use of technologies for increasing oil recovery from the oilfields with hard-to-recover reserves under natural development mode and thermal steam influence, including the deposits of high-viscosity oils. Technologies are environmentally friendly and technologically efficient. To implement the technologies, acid and alkaline oil-displacing compositions based on surfactants and buffer systems with adjustable viscosity and high oil-displacing ability have been developed. The results of laboratory studies of phase equilibria, physicochemical, acid-base and rheological properties in surfactant - DES systems containing polybasic acid, polyols, urea, aluminium and ammonium salts are presented. The developed compositions possess the following advantages: they are compatible with formation waters, low-freezing ((-20)-(-60) °С) or solid, have low interfacial tension at the boundary with oil, applicable in a wide temperature range (10-200 °C). The industrial use of these technologies will make it possible to extend the profitable operation of fields with hard-to-recover oil in a wide range of climatic conditions, including the Arctic.

Development and operation of wells at oil and gas fields are often accompanied by unexpected complications related to drilling mud loss and breakthrough of gas and fluids through reservoir fractures, which requires repair and insulation operations (RIO) to be performed with adequate quality. The ways to improve the efficiency of repair and insulation operations in oil and gas wells with the use of gel-forming plugging materials are considered in the work. The use of various hydrophilic and hydrophobic dispersed and fibrous fillers in hydrogels based on polyacrylamide and complex organic crosslinker is proposed in order to improve their rheological properties and increase the blocking ability. Such organic-inorganic composites show a variety of rheological properties, which makes it possible to select the necessary hydrogel compositions for certain RIO. The results of rheological (oscillation) and filtration studies, as well as field tests of the compositions, are presented. Chrysotile, carbon black, hydrophilic nanosilica, and mechanically activated wood flour, rice husk, hydrolysed lignin were used as dispersed fillers in oscillation studies. Polypropylene fibres, basalt fibres and carbon fibres were considered as fibre fillers. The values of elastic modulus (G') and viscosity modulus (G''), crossover points and linear viscoelastic regions for each composition were determined from the results of oscillation studies. An increase in the modulus of elasticity up to 48 % (G' = 53.3 Pa) was achieved with the addition of carbon black and up to 50 % (G' = 54.2 Pa) for the composition with chrysotile and carbon fibre, compared to the base hydrogel without fillers (G' = 36.1 Pa). The addition of hydrophilic nanosilica allowed an increase in the yield strength (crossover point) by more than 300 % (to 210.4 Pa). Filtration studies were performed on the ideal fracture model with different opening (50, 100, 650 mm) using natural core samples. It has been established that during water filtration the hydrogel with chrysotile and polypropylene fibre additives has a higher residual resistance factor (RRF = 167) in the fracture with 100 μm opening than the base hydrogel (RRF = 136) in the 50 μm fracture. When blocking a gas-saturated model of an ideal fracture, the maximum RRF was 2677. Field tests of the composition with dispersed and fibre fillers for elimination of catastrophic drilling mud circulation loss and RIO were successful.