In this paper, the effect of an iron oxide additive of man-made origin (based on iron-containing sludge) on the composition of coffee ground pyrolysis products is investigated. Coffee cake, a massive secondary product of coffee processing, was used as the starting material. The pyrolysis process was carried out at a temperature of 550 °C in an inert nitrogen atmosphere at various mass fractions of the catalyst (5-50 wt.%). Pyrolysis was performed in a glass reactor, which excluded the influence of reactor material on the composition of pyrolysis products. It is shown that the introduction of an iron oxide additive has no significant effect on the specific surface area of the solid residue. However, the coffee cake itself affects the size of the coherent iron oxide scattering regions: an increase in the content of the former leads to a decrease in these values. Nevertheless, the phase composition of solid pyrolysis products does not fundamentally change with varying catalyst content, which has been established by X-ray phase analysis. The iron oxide additive has the most significant effect on the composition of liquid pyrolysis products. Chromatography mass spectrometry revealed the formation of a complex mixture of oxygen-containing organic compounds and organometallic components, the relative yield of which significantly depends on the content of the catalyst. The presence of characteristic bands responsible for organometallic compounds has been confirmed by infrared spectrometry in samples of solid pyrolysis products. Bands responsible for carboxylic acids, aldehydes, ketones, and nitrogen-containing compounds were found in liquid samples of pyrolysis products. Gaseous pyrolysis products were mainly represented by water vapor, nitrogen and carbon dioxide. The results obtained demonstrate the possibility of regulating the composition of the products of the biomass pyrolysis process by introducing iron oxide catalytically active additives. For citation: Le Thi Mai Huong, Afineevskii A.V., Smirnov D.V., Gordina N.E. Use of iron oxide sludge in the process of pyrolysis of coffee ground. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2026. V. 69. N 6. P. 98-106. DOI: 10.6060/ivkkt.20266906.7050.

A new polymer sorbent with high absorption capacity for heavy metal ions was obtained by condensation of o-phenylenediamine, epoxy resin, formaldehyde and ethylenediamine at a molar ratio of components of 2:1:2:2. In accordance with the original components, the sorbent was named o-PhDEP. The composition of the obtained sorbent has been confirmed with IR spectroscopy and elemental analysis. The IR spectra of the polymer and the key initial reagent, o-phenylenediamine, were compared. The optimal conditions for the processes of sorption and desorption of metals by the new sorbent were studied. It was found that it has high absorption (sorbing) capacity for such ions as Cu2+, Co2+, Cd2+, Zn2+, Ni2+. The adsorption capacity of o-PhDEP sorbent for these ions was determined. It is suggested that it could be used to remove heavy metals from industrial wastewater. The dependence of the Cu2+ ion sorption process on the pH value of the environment was studied. It has been established that the static exchange capacity of the polymer sorbent has the highest value in the range of pH=3-5. It has been proven that the new sorbent can be purified from heavy metals by desorption in a weakly acidic environment and then reused. Using a scanning electron microscope, an image of the sorbent's surface was obtained. It was found to have a developed porous structure, which contributes to its absorption capacity. The synthesized polymer o-PhDEP was first used to absorb micro and nanoplastics from an aqueous solution and vegetable oil. It has been established that plastic particles are completely adsorbed by the presented polymer. The content of micro and nano plastics in the initial and post-sorption solutions was determined using the Laser Dynamic Light Scattering method. For citation: Kornilov K.N., Roeva N.N., Yakovlyuk R.O. Synthesis and study of a polymer sorbent based on ortho-diaminobenzene and epoxy resin for water and food purification from heavy metals and microplastics. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2026. V. 69. N 3. P. 75-86. DOI: 10.6060/ivkkt.20266903.6742.

The reactivity of zinc and chromium (III) oxides, hydroxides and salts (nitrates), as well as the xerogel combustion product (XCP) obtained from a solution of zinc and chromium (III) nitrates with the addition of citric acid, in the reaction of ZnCr2O4 spinel formation was analyzed. Reaction mixtures were prepared by simple mixing of components, as well as under conditions of mechanical activation or microwave processing. Effective constants of reaction rate and product yield were used to estimate the reactivity. A higher rate of the reaction involving hydroxides and salts compared to oxides is shown due to the activation of reagents during thermolysis. It has been established the increased activity of zinc and chromium (III) nitrates and XCP, which was a pre-prepared substance in which the main part of the gases (water vapor, CO2, N2, partially nitrogen oxides) was removed during combustion, leaving the oxide components in an active form, which were subsequently brought into close contact by compression. This distinguished XCP from a mixture of zinc and chromium (III) nitrates, in which gas emission during burning occurred in previously pressed tablets, which reduced the contact area of the reagents. The effect of mechanical activation and microwave treatment of reagents, during which a significant part of the precursors thermolysis took place, was analyzed. The newly formed oxide components actively interacted, and at the final stage of firing, a significant portion of the defects had time to heal. The spinel yield at different temperatures from mixtures consisting of zinc and chromium oxides/hydroxides without machining and after treatment in a planetary mill (PM) was compared, as well as the yield of ZnCr2O4 from mixtures with different preparation methods before burning at a constant temperature (1000 °C, 1 h). The maximum yield was observed when XCP or a mixture of zinc and chromium nitrates were used as precursors. A high reactivity of XCP was noted in the spinel formation without additional pretreatment. With an increase in the burning temperature, the spinel lattice was naturally ordered, which was confirmed by a decrease in the cell parameter and an increase in the size of crystallites. For citation: Filatova N.V., Kosenko N.F., Pavlova K.A., Fedorova G.S. Mechanical and microwave activation of solid-phase synthesis of zinc-chromite spinel. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2026. V. 69. N 3. P. 48-56. DOI: 10.6060/ivkkt.20266903.6885.

Thermodynamic parameters (pK, ΔdisG, ΔdisH, ΔdisS) for protolytic equilibria of D,L-valyl-glycine (HL) in aqueous solutions have been evaluated at 298.15 K and ionic strengths of 0.1, 0.5, 1.0 mol/L. Potassium nitrate was used as the background electrolyte. The stepwise dissociation constants of the dipeptide were determined using a method of potentiometrical titration. To determine the equilibrium concentration of hydrogen ions, the EMF of a circuit consisting of a glass electrode and an saturated silver – silver chloride electrode was measured. The heat effects of the dipeptide dissociation were determined via direct calorimetry. The heats of mixing of solutions of nitric acid with solutions of the dipeptide solutions were measured in the areas of pH 3.8→2.7 and 8.5→7.5. The heats of dilution for the dipeptide solution with a background electrolyte at the corresponding ionic strengths were also measured applying necessary corrections. The standard thermodynamic characteristics of the protolytic equilibria are calculated using results from thermochemical and potentiometric studies performed under identical conditions: рКº(Н2L+)= 3.20±0.05, ΔdisGº(Н2L+)= 18.27±0.29 kJ/mol, ΔdisHº(Н2L+)= 0.58±0.14 kJ/mol, ΔdisSº(Н2L+)= –59.3±1.1 J/mol∙K and рКº(НL)= 8.24±0.03, ΔdisGº(НL)= 47.03±0.17 kJ/mol, ΔdisHº(НL)= 44.94±0.21 kJ/mol, ΔdisSº(НL)= –7.0±0.9 J/mol∙K. The stoichiometric constants and enthalpies of the reactions were extrapolated to the zero ionic strength by equations with one individual parameter. The values of the thermodynamic parameters obtained for D,L-valyl-glycine were compared to the relevant data for some related compounds investigated earlier in our laboratory using similar experimental procedures. Dependences of the thermodynamic characteristics for the dissociation reactions of aliphatic dipeptides on a side substituent hydrophobicity of the C- and N-terminal amino acid residue in series -H < -CH3 < -CH(CH3)2 < -CH2CH(CH3)2 have been discussed. For citation: Gridchin S.N. Thermodynamic characteristics of protolytic equilibria of D,L-valyl-glycine in an aqueous solution. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2026. V. 69. N 2. P. 59-63. DOI: 10.6060/ivkkt.20266902.7233.

The stable operation of electrochemical devices, strict impurity content standards must be met. For example, organic electrolytes, which serve as key components in supercapacitor assembly or can be used as additives in electrode fabrication, are subject to such requirements. This paper proposes a convenient method for purifying 1,1'-bispyropyrrolidinium tetrafluoroborate (SBP-BF4), which enables the production of a highly pure target product, thereby enabling its use in the modern electrochemical industry. Developed purification method is based on recrystallization using a binary solvent system, relying on the selection the optimal water-to-alcohol ratio. The most effective binary mixture for recrystallization was found to be isopropyl alcohol and water in a mass fraction of 95:5. After a single recrystallization, it is possible to achieve a minimum content of cations, whereas after three recrystallizations, it is possible to minimize the content of halide anions in the target product. This method allows achieving the following quality indicators the final product: the content of metal cations Na+ and K+ is less than 5 ppm; the total concentration of halogen anions (Cl- and Br-) is less than 100 ppm. The following analytical methods were used to control the quantitative content of interfering ions: atomic emission spectroscopy allowed us to determine the content of sodium and potassium cations; direct potentiometry with ion-selective electrodes allows us to determine the content of chloride and bromide anions. Synthesis the target organic electrolyte SBP-BF4 was carried out by the interaction pyrrolidine and 1,4-dibromobutane in the presence sodium tetrafluoroborate according to a known method. To confirm the qualitative composition the obtained organic electrolyte, the NMR spectroscopy method was used on 1H and 13C nuclei in DMSO-d6. For citation: Novolokov K.Yu., Bakibaev A.A., Knyazev A.S. Purification of organic electrolyte – 1,1’-bispyropyrrolidinium tetrafluoroborate. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2026. V. 69. N 2. P. 72-77. DOI: 10.6060/ivkkt.20266902.6780.

The processes proceeding in the neutral and weakly acidic aqueous solutions, containing aquacobalamin (H2OCbl) – sulfur complex with cucurbit[7]uril (S8/CB[7]) – L-cysteine (L-glutathione), have been studied for the first time. It is shown that, in contrast to the system aquacobalamin – L-cysteine, in the three-component system the formation of reduced cobalamin (cob(II)alamin, Cbl(II)) has not found, though concentration of H2OCbl in weakly acidic solutions decreases in time. The rate of this decrease does not depend on S8/CB[7]. In neutral solutions concentration of H2OCbl in the presence of S8/CB[7] does not change in time; the reason is the reverse reaction of reduced cobalamin with complex S8/CB[7], resulting in the formation of initial aquacobalamin. In neutral solutions this reaction proceeds faster than in weakly acidic. The comparative study of the influence of aquacobalamin on reducing ability of L-cysteine and L-glutathione in their reaction with S8/CB[7] has been made. It is shown that the products of reactions in the system S8/CB[7] – aquacobalamin – L-cysteine or L-glutathione are polysulfides and hydrogen sulfide, and the formation of these products proceeds faster with L-cysteine. It is also found that in the presence of aquacobalamin the rate of polysulfide formation is much higher. The scheme of the processes proceeding in the system H2OCbl – complex S8/CB[7] – thiol is proposed. It is found that the influence of aquacobalamin on the reduction of sulfur to hydrogen sulfide is manifested in the thiol activation due to its complexation with Cbl(III) and the formation of additional reductant (Cbl(II)); its oxidation by sulfur leads to the formation of initial aquacobalamin. For citation: Molodtsov P.A., Makarov S.V., Kuchina D.E., Naidenko E.V. Influence of aquacobalamin on the interaction of the cucurbit[7]uril-sulfur complex with thiols. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2026. V. 69. N 1. P. 14-20. DOI: 10.6060/ivkkt.20266901.7278.

Fe/Al bentonites were synthesized by modifying bentonite clay with iron and aluminum polyoxocomplexes at different iron and aluminum molar ratios. The chemical composition was determined, and the structure and physicochemical properties of the materials were studied using a set of methods (scanning electron microscopy with an energy-dispersive microanalysis system, X-ray phase analysis, low-temperature nitrogen adsorption). Modification of bentonite clay with Fe/Al complexes resulted in an increase in the iron and aluminum content, an increase in the interplanar distance and specific surface area, and a change in the morphology of bentonite clay particles. The iron and aluminum content in the obtained materials was 7.57-14.74% and 10.84-13.45%, respectively. The specific surface area of the materials was 108-137 m2/g. The Fe/Al bentonite particles were presented as loose microaggregates of various shapes and sizes with a greater number of pores compared to bentonite clay. The adsorption properties of the materials were tested in the adsorption of anthraquinone dye Acid Bright Blue, which is widely used in the textile industry and is found in industrial wastewater. The results showed that the adsorption capacity of the modified materials for the dye exceeded the adsorption capacity of bentonite clay by 8-13 times, which is due to the increase in the number of adsorption centers (Fe/Al)-OH and the specific surface. The adsorption of the dye on the modified materials was 10.5-11.3 mg/g at pH 6.0 and increased to 21.8-28.3 mg/g at pH 4.0. The obtained materials can be used in the purification of textile industry wastewater from anthraquinone dyes. For citation: Badmaeva S.V., Khankhasaeva S.Ts., Ukhinova M.V. Synthesis, physical-chemical and adsorption properties of Fe/Al-bentonites. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2025. V. 68. N 10. P. 87-94. DOI: 10.6060/ivkkt.20256810.7209.

Nine novel benzo[d]thiazole derivatives (E1 – E9) featuring an amide bond were synthesized via an efficient coupling reaction between carboxylic acids and amines using hexafluorophosphate azabenzotriazole tetramethyl uronium (HATU) as the coupling reagent. The reaction was carried out under mild conditions, affording the desired products in high yields (75 – 90%). Structural characterization of the synthesized compounds was achieved using modern spectroscopic techniques, including infrared (IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and mass spectrometry (MS), which confirmed the formation of the targeted benzo[d]thiazole scaffolds. In addition to the synthetic work, the biological activities of selected compounds were evaluated. Cytotoxic activity was assessed against the carcinoma cell line (KB), revealing that compounds E1, E3, E4, E6, and E7 exhibited moderate inhibitory effects, with IC₅₀ values of 48.29, 115.46, 89.36, 84.09, and 121.89 µg/mL, respectively. However, compounds E6 and E7 did not show significant cytotoxicity against other cancer cell lines such as Hep-G2, A549, and MCF7, nor did they demonstrate noteworthy antioxidant activity. Furthermore, compounds E1, E2, E3, E4, E5, and E8 were inactive against both Gr(+) and Gr(-) bacteria as well as fungal strains. These findings provide valuable insight into the structure – activity relationships of benzo[d]thiazole derivatives and support their potential development as anticancer agents. For citation: Nguyen Duc Du, Pham Huu Dien, Nguyen Thi Thach Thao, Nguyen Thi Ngoc Mai, Nguyen Van Dat, Duong Quoc Hoan Synthesis and biological activities of some benzo[d]thiazole derivatives containing an amide bond. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2025. V. 68. N 10. P. 19-25. DOI: 10.6060/ivkkt.20256810.7227.

In this work, graphite foil was obtained from thermally expanded graphite based on intercalated compounds of graphite with nitric acid of stages IV, III, II. The foil was obtained using standard technological operations, including intercalation of nitric acid into graphite, hydrolysis of interstitial compounds, exfoliation of oxidized graphite using thermal shock and rolling of thermally expanded graphite into graphite foil. The structure of the obtained intercalated compounds of graphite and the formation of a certain stage were confirmed by X-ray phase analysis. The morphology and elemental analysis for intermediate products (oxidized graphite and thermally expanded graphite) and the final graphite foil were studied by scanning electron microscopy. It was demonstrated that there are no traces of nitric acid in the products after thermal exfoliation. It has been established that during oxidation of graphite foil, its surface becomes more defective, and graphite foil based on intercalated compounds of stage IV graphite exhibits greater thermal resistance than lower stages of intercalation. Mechanical tests have shown greater tensile strength of graphite foil based on intercalated compounds of graphite with nitric acid of stage II, as well as a decrease in the strength of graphite foil during oxidation. Tests of the tightness of seals made of graphite foil have shown a decrease in the tightness level of a flange gasket made of graphite foil during its oxidation at elevated temperatures in an air atmosphere. In addition, it has been shown that the required compression force to ensure a given tightness level increases with an increase in the number of the stage of intercalation of nitric acid into graphite. For citation: Efimov D.V., Ivanov A.V., Mukhanov V.A., Lukyantsev M.I., Maksimova N.V., Avdeev V.V. Influence of thermal oxidation processes on the mechanical properties of graphite foil. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2025. V. 68. N 9. P. 83-89. DOI: 10.6060/ivkkt.20256809.2y.

The oxidation processes under the action of ferrates and combined plasma action in the presence of ferrates on aqueous solutions of phenol and 2,4-dichlorophenol (with initial concentrations of organic compounds of 1-100 mg/l) were studied. The ferrate used in the process of cleaning model solutions was synthesized chemically by dissolving Fe(NO3)3·9H2O in an alkaline solution of NaClO4, followed by heating the resulting mixture. The ferrate concentration in the experiments was constant and amounted to 0.1 g/l. The volume ratio in the "processed solution - ferrate" systems was 10:1. When ferrates acted on the studied solutions, the destruction of 2,4-dichlorophenol proceeds more efficiently than in the case of using a dielectric barrier discharge (the destruction efficiency is 43% and 59%, respectively). For model phenol solutions, the destruction efficiency was the same (no more than 37%). Introduction of ferrate into the discharge zone of plasma resulted in significant increase in the destruction efficiency of the organic compounds under study (up to 86% for phenol and 92% for 2,4-dichlorophenol). It was shown that destruction of organic compounds is described by a 1st order kinetic equation, solution of which allowed estimating effective rate constants and rates of phenol and 2,4-dichlorophenol decomposition. The mechanism of synergistic effect of organic compound oxidation in the plasma-ferrate system is due to interaction of the following systems: 1) effect of dielectric barrier discharge on aqueous solutions, resulting in formation of active particles; 2) chemical reactions between FeO24- present in solution and active plasma particles; 3) reactions of oxidizing agents with organic compounds, which include direct oxidation with ferrate (VI) (with a redox potential of 2.20 V) and active particles formed in the combined process. For citation: Klipov N.V., Kvitkova E.Yu., Izvekova T.V., Gusev G.I., Le Thi Mai Huong, Gordina N.E., Gushchin A.A. Oxidation of supertoxicants in a dielectric barrier discharge in the presence of ferrates. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2025. V. 68. N 9. P. 126-133. DOI: 10.6060/ivkkt.20256809.7273.