Pub Date : 2022-04-07DOI: 10.33581/2520-257x-2022-1-61-71
A. Dudko, M. Horetski, N. Frolova, Y. Faletrov, V. Shkumatov
A fluorescent molecular rotor (FMR) based on boron dipyrromethene core was obtained. Fluorescence emission properties of the compound strongly depend on the medium viscosity. The emission intensity increases 27 times after viscosity changing from ethanol to glycerol medium. At the same time, the compound appeared almost insensitive to solvatochromic effects. Obtained FMR also can affinely bind with the bovine serum albumin protein active sites followed by noticeable emission intensity growth. Possible ligand binding cites and main amino acid surrounding were described with molecular docking simulations and are in an agreement with experimental data. The results can be used for further design and synthesis of novel fluorescent viscosity and protein-ligand interactions censors suitable for implementation in biosystems in vitro and in vivo.
{"title":"Fluorescent properties and protein-ligand interactions of boron dipyrromethene molecular rotor","authors":"A. Dudko, M. Horetski, N. Frolova, Y. Faletrov, V. Shkumatov","doi":"10.33581/2520-257x-2022-1-61-71","DOIUrl":"https://doi.org/10.33581/2520-257x-2022-1-61-71","url":null,"abstract":"A fluorescent molecular rotor (FMR) based on boron dipyrromethene core was obtained. Fluorescence emission properties of the compound strongly depend on the medium viscosity. The emission intensity increases 27 times after viscosity changing from ethanol to glycerol medium. At the same time, the compound appeared almost insensitive to solvatochromic effects. Obtained FMR also can affinely bind with the bovine serum albumin protein active sites followed by noticeable emission intensity growth. Possible ligand binding cites and main amino acid surrounding were described with molecular docking simulations and are in an agreement with experimental data. The results can be used for further design and synthesis of novel fluorescent viscosity and protein-ligand interactions censors suitable for implementation in biosystems in vitro and in vivo.","PeriodicalId":17303,"journal":{"name":"Journal of the Belarusian State University. Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-04-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86078696","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-06DOI: 10.33581/2520-257x-2022-1-72-82
A. Kudaka, T. N. Vorobyova
The compositions of aqueous chloride-fluoride and ethylene glycol citrate electrolytes and conditions for electrochemical deposition of Ni – Sn coatings, providing the production of an alloy based on Ni3Sn2 intermetallic with nickel content of 36– 40 wt. %, have been proposed. The effect of sodium and ammonium fluorides additives, as well as non-ionic surfactant OS-20 in an aqueous electrolyte or hydrochloric and citric acids in ethylene glycol electrolyte on the internal stresses and corrosion resistance of coatings has been determined. The lowest internal stresses and the highest corrosion resistance have been found to be characteristic of coatings with a fine-grained dense structure that does not change with increasing of thickness (within 1–10 μm), which include a Ni3Sn2 single crystalline phase with minimal deviations from stoichiometry. To the greatest extent, these characteristics are provided during the deposition of coatings from ethylene glycol citrate electrolyte.
{"title":"Properties of nickel – tin coatings deposited from aqueous and non-aqueous electrolytes","authors":"A. Kudaka, T. N. Vorobyova","doi":"10.33581/2520-257x-2022-1-72-82","DOIUrl":"https://doi.org/10.33581/2520-257x-2022-1-72-82","url":null,"abstract":"The compositions of aqueous chloride-fluoride and ethylene glycol citrate electrolytes and conditions for electrochemical deposition of Ni – Sn coatings, providing the production of an alloy based on Ni3Sn2 intermetallic with nickel content of 36– 40 wt. %, have been proposed. The effect of sodium and ammonium fluorides additives, as well as non-ionic surfactant OS-20 in an aqueous electrolyte or hydrochloric and citric acids in ethylene glycol electrolyte on the internal stresses and corrosion resistance of coatings has been determined. The lowest internal stresses and the highest corrosion resistance have been found to be characteristic of coatings with a fine-grained dense structure that does not change with increasing of thickness (within 1–10 μm), which include a Ni3Sn2 single crystalline phase with minimal deviations from stoichiometry. To the greatest extent, these characteristics are provided during the deposition of coatings from ethylene glycol citrate electrolyte.","PeriodicalId":17303,"journal":{"name":"Journal of the Belarusian State University. Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83573399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-06DOI: 10.33581/2520-257x-2022-1-53-60
D. Belov, Y. Faletrov, P. Yakovets, V. Shkumatov
Polylactide (PLA) is one of the most promising biodegradable and biocompatible polymer materials. Estimation of hydrolytic destruction of PLA is of high importance for their applications both at planning and at real-time exploitation. This paper reports on synthesis and applicability of fluorescein-O-dihexanoate as a pro-fluorescent marker of hydrolytic destruction of two types of PLA-based materials. Fluorescence enhancement correlated with adequately more fast destruction of poly-D,L-lactide as well as less stability to alkaline hydrolysis. Thus, applicability of fluorescein-O-dihexanoate for fluorescence-based estimation of hydrolytic destruction of PLA-based materials is shown in quite real time mode.
聚乳酸(PLA)是一种极具生物可降解和生物相容性的高分子材料。聚乳酸水解破坏的估算对其在规划和实时开发中的应用具有重要意义。本文报道了荧光素- o-二己酸酯作为两类pla基材料水解破坏的促荧光标记物的合成及其应用。荧光增强与多聚d -l -丙交酯的快速破坏和碱性水解稳定性差相关。因此，荧光素- o -二己酸酯在基于荧光的估计pla基材料水解破坏的适用性显示在相当实时的模式。
{"title":"Fluorescein dihexanoate as a profluorescent marker for monitoring of hydrolytic descruction of polylactide-based materials","authors":"D. Belov, Y. Faletrov, P. Yakovets, V. Shkumatov","doi":"10.33581/2520-257x-2022-1-53-60","DOIUrl":"https://doi.org/10.33581/2520-257x-2022-1-53-60","url":null,"abstract":"Polylactide (PLA) is one of the most promising biodegradable and biocompatible polymer materials. Estimation of hydrolytic destruction of PLA is of high importance for their applications both at planning and at real-time exploitation. This paper reports on synthesis and applicability of fluorescein-O-dihexanoate as a pro-fluorescent marker of hydrolytic destruction of two types of PLA-based materials. Fluorescence enhancement correlated with adequately more fast destruction of poly-D,L-lactide as well as less stability to alkaline hydrolysis. Thus, applicability of fluorescein-O-dihexanoate for fluorescence-based estimation of hydrolytic destruction of PLA-based materials is shown in quite real time mode.","PeriodicalId":17303,"journal":{"name":"Journal of the Belarusian State University. Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84148359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-30DOI: 10.33581/2520-257x-2022-1-43-52
J. Panada, V. Klopava, T. Kulahava, Y. Faletrov, M. Horetski, N. Frolova, S. Koran, E. Fomina, V. Shkumatov
A 3-acetyl analogue of 5-hydroxyindole was synthesised and evaluated for its effects on rat C6 glioma cell functions. It was found that 3-acetyl-5-hydroxy-2-methylindole at 10 μmol/L led to a sharp reduction of mitochondrial membrane potential, induction of autophagy and decrease of proliferation of C6 glioma cells. The compound’s effect was comparable to that of rotenone, an inhibitor of cell respiration.
{"title":"Influence of 3-acetyl-5-hydroxy-2-methylindole on glioma cell proliferation and metabolism","authors":"J. Panada, V. Klopava, T. Kulahava, Y. Faletrov, M. Horetski, N. Frolova, S. Koran, E. Fomina, V. Shkumatov","doi":"10.33581/2520-257x-2022-1-43-52","DOIUrl":"https://doi.org/10.33581/2520-257x-2022-1-43-52","url":null,"abstract":"A 3-acetyl analogue of 5-hydroxyindole was synthesised and evaluated for its effects on rat C6 glioma cell functions. It was found that 3-acetyl-5-hydroxy-2-methylindole at 10 μmol/L led to a sharp reduction of mitochondrial membrane potential, induction of autophagy and decrease of proliferation of C6 glioma cells. The compound’s effect was comparable to that of rotenone, an inhibitor of cell respiration.","PeriodicalId":17303,"journal":{"name":"Journal of the Belarusian State University. Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84093108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-23DOI: 10.33581/2520-257x-2022-1-31-42
S. Leschev, Y. Pakhadnia, Aliaksandr A. Ahabalayeu, M. Zayats
The extraction of anabolic steroids (1,4-androstadiene-3,17-dione; 17α-methyltestosterone; 19-norethiocholanolone; 4-hydroxytestosterone; 4-androstene-3,17-dione; 5α-androstane-3β,17β-diol; dehydroepiandrosterone; calusterone; clostebol; methandienone; methyldienolone; nandrolone; testosterone; epitestosterone; tibolone; 19-norandrostenedione; 1-methylene-5α-androstan-3α-ol-17-one) by aqueous-organic mixtures from hexane solutions was studied at the temperature (20 ± 1) °C. Based on the experimental data obtained, the partition ratios of anabolic steroids were calculated, which were used to optimise the standard sample preparation procedure in the process of determining the compounds under study in biologically active dietary supplements and specialised sports nutrition. It was found that the most effective and selective extractants from hydrocarbon solutions are water-acetonitrile mixtures containing from 10 to 20 % by volume of water. An extraction technique has been developed for sample preparation of biologically active dietary supplements for subsequent gas chromatographic determination of anabolic steroids in them using a triple quadrupole mass spectrometric detector. The proposed method is characterised by a standard deviation of 10–15 % and a detection limit about 10 μg/kg of biologically active dietary supplements, which makes it possible to reliably determine impurities of prohibited anabolic steroids in them.
{"title":"Extraction of anabolic steroids with aqueous-organic mixtures from hexanic solutions","authors":"S. Leschev, Y. Pakhadnia, Aliaksandr A. Ahabalayeu, M. Zayats","doi":"10.33581/2520-257x-2022-1-31-42","DOIUrl":"https://doi.org/10.33581/2520-257x-2022-1-31-42","url":null,"abstract":"The extraction of anabolic steroids (1,4-androstadiene-3,17-dione; 17α-methyltestosterone; 19-norethiocholanolone; 4-hydroxytestosterone; 4-androstene-3,17-dione; 5α-androstane-3β,17β-diol; dehydroepiandrosterone; calusterone; clostebol; methandienone; methyldienolone; nandrolone; testosterone; epitestosterone; tibolone; 19-norandrostenedione; 1-methylene-5α-androstan-3α-ol-17-one) by aqueous-organic mixtures from hexane solutions was studied at the temperature (20 ± 1) °C. Based on the experimental data obtained, the partition ratios of anabolic steroids were calculated, which were used to optimise the standard sample preparation procedure in the process of determining the compounds under study in biologically active dietary supplements and specialised sports nutrition. It was found that the most effective and selective extractants from hydrocarbon solutions are water-acetonitrile mixtures containing from 10 to 20 % by volume of water. An extraction technique has been developed for sample preparation of biologically active dietary supplements for subsequent gas chromatographic determination of anabolic steroids in them using a triple quadrupole mass spectrometric detector. The proposed method is characterised by a standard deviation of 10–15 % and a detection limit about 10 μg/kg of biologically active dietary supplements, which makes it possible to reliably determine impurities of prohibited anabolic steroids in them.","PeriodicalId":17303,"journal":{"name":"Journal of the Belarusian State University. Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85366332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-22DOI: 10.33581/2520-257x-2022-1-18-30
Y. N. Yurkshtovich, A. Blokhin
Temozolomide (4-methyl-5-oxo-2,3,4,6,8-pentazabicyclo[4,3,0]nona-2,7,9-triene-9-carboxamide) is an active component of antitumor immunosuppressive alkylating drugs, and it used largely for the treatment of various types of malignant tumors, including malignant gliomas that are difficult to treat by surgery (glioblastoma multiforme and anaplastic astrocytoma). Wide field of temozolomide application dictates the need for its comprehensive thermodynamic study. In this work temperature dependance of the temozolomide heat capacity was obtained using the adiabatic calorimetry method and the standard thermodynamic functions of crystalline temozolomide were calculated in the temperature range 80–370 K. Standard thermodynamic functions of the temozolomide in the ideal gas state were calculated using the statistical thermodynamics approach in the temperature range 0–1000 K. To obtain the standard internal energy and enthalpies of combustion and formation of crystalline temozolomide at T = 298.15 K the combustion bomb calorimetry was used. Standard enthalpy of formation of the gaseous temozolomide was calculated in the framework of the isodesmic reactions method using quantum chemical computing. To calculate standard sublimation enthalpy of temozolomide the electrostatic potential model was applied. The results obtained can find application in solving problems of optimisation of temozolomide production processes and to validate experimentally obtained values of thermodynamic properties of the temozolomide.
{"title":"Thermodynamic properties of temozolomide in crystalline and gaseous aggregate states","authors":"Y. N. Yurkshtovich, A. Blokhin","doi":"10.33581/2520-257x-2022-1-18-30","DOIUrl":"https://doi.org/10.33581/2520-257x-2022-1-18-30","url":null,"abstract":"Temozolomide (4-methyl-5-oxo-2,3,4,6,8-pentazabicyclo[4,3,0]nona-2,7,9-triene-9-carboxamide) is an active component of antitumor immunosuppressive alkylating drugs, and it used largely for the treatment of various types of malignant tumors, including malignant gliomas that are difficult to treat by surgery (glioblastoma multiforme and anaplastic astrocytoma). Wide field of temozolomide application dictates the need for its comprehensive thermodynamic study. In this work temperature dependance of the temozolomide heat capacity was obtained using the adiabatic calorimetry method and the standard thermodynamic functions of crystalline temozolomide were calculated in the temperature range 80–370 K. Standard thermodynamic functions of the temozolomide in the ideal gas state were calculated using the statistical thermodynamics approach in the temperature range 0–1000 K. To obtain the standard internal energy and enthalpies of combustion and formation of crystalline temozolomide at T = 298.15 K the combustion bomb calorimetry was used. Standard enthalpy of formation of the gaseous temozolomide was calculated in the framework of the isodesmic reactions method using quantum chemical computing. To calculate standard sublimation enthalpy of temozolomide the electrostatic potential model was applied. The results obtained can find application in solving problems of optimisation of temozolomide production processes and to validate experimentally obtained values of thermodynamic properties of the temozolomide.","PeriodicalId":17303,"journal":{"name":"Journal of the Belarusian State University. Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85560306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-16DOI: 10.33581/2520-257x-2022-1-3-17
P. Malakhovsky, Alexey V. Rashkevich, E. A. Minakov, M. Artemyev
We studied the aggregative stability of colloidal silver quasi-spherical nanoparticles and two-dimensional nanoplates, stabilised by 11-mercaptoundecanoic acid, in the presence of phosphate buffers containing different singly charged cations (Li+ , Na+ , K+ , Cs+) and tris-HCl at pH 8.0 and concentration 0.02 mol/L which mimics the carbodiimide conjugation conditions of nanoparticles with biomolecules. Aggregation of silver nanoplates occurs in the presence of Na-phosphate buffer whereas at the same conditions the quasi-spherical nanoparticles retain colloidal stability. The difference in colloidal stability between 3D and 2D silver nanoparticles is due to the increase of the apparent acid dissociation constant on the nanoplates’ basal faces and the subsequent increase in specific bridging interactions nanoparticle – cation – nanoparticle which can be eliminated by introducing of non-ionic spacer (11-mercapto-1-undecanol) in the ligand layer. Silver nanoplates with mixed ligand layer have increased colloidal stability across the pH.
{"title":"Aggregative stability of colloidal 3D and 2D silver nanoparticles, stabilised by 11-mercaptoundecanoic acid, in the presence of singly charged cations","authors":"P. Malakhovsky, Alexey V. Rashkevich, E. A. Minakov, M. Artemyev","doi":"10.33581/2520-257x-2022-1-3-17","DOIUrl":"https://doi.org/10.33581/2520-257x-2022-1-3-17","url":null,"abstract":"We studied the aggregative stability of colloidal silver quasi-spherical nanoparticles and two-dimensional nanoplates, stabilised by 11-mercaptoundecanoic acid, in the presence of phosphate buffers containing different singly charged cations (Li+ , Na+ , K+ , Cs+) and tris-HCl at pH 8.0 and concentration 0.02 mol/L which mimics the carbodiimide conjugation conditions of nanoparticles with biomolecules. Aggregation of silver nanoplates occurs in the presence of Na-phosphate buffer whereas at the same conditions the quasi-spherical nanoparticles retain colloidal stability. The difference in colloidal stability between 3D and 2D silver nanoparticles is due to the increase of the apparent acid dissociation constant on the nanoplates’ basal faces and the subsequent increase in specific bridging interactions nanoparticle – cation – nanoparticle which can be eliminated by introducing of non-ionic spacer (11-mercapto-1-undecanol) in the ligand layer. Silver nanoplates with mixed ligand layer have increased colloidal stability across the pH.","PeriodicalId":17303,"journal":{"name":"Journal of the Belarusian State University. Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73822393","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-22DOI: 10.33581/2520-257x-2021-2-62-73
S. M. Leschev, T. Henarava
Currently, there is an increase in the production of carbon nanomaterials in the world, which is associated with their unique physical and mechanical properties and their use in various fields of science, industry and technology. Investigation of the chemical composition of waste gases from a propane-butane mixture pyrolysis unit during the synthesis of carbon nanomaterials is of scientific and applied value, since it allows one to study both the chemistry of the pyrolysis process of hydrocarbon mixtures and determine the degree of toxicity of waste gas from pyrolysis units. The quantitative determination of polycyclic aromatic hydrocarbons in the gaseous products of pyrolysis of a propane-butane mixture during the synthesis of carbon nanomaterials has shown that when sampling with a small amount of the Supelpak-2 adsorbent, which is widely used in international and domestic methods, efficient capture of multinuclear aromatic hydrocarbons is not ensured. Therefore, an important research issue is the development of a simple and effective method for sampling polycyclic aromatic hydrocarbons with their subsequent GC-MS analysis. The principal essence of the technique is the impregnation of two fiberglass filters with an organic low-volatile solvent – diethylene glycol, tetraethylene glycol or dimethyl sulfoxide. The latter is characterised by the highest extracting power in relation to polycyclic aromatic hydrocarbons. The developed technique makes it possible to increase the efficiency of capturing multinuclear aromatic hydrocarbons (with four or more rings in a molecule) to 96–98 % compared to a solid adsorbent under equal conditions (pyrolysis conditions, weight of adsorbent equal with filters impregnated with a solvent), where the degree of their extraction is 1–5 %. The established values of the degree of recovery of the measured components are explained by the high extracting ability of dimethyl sulfoxide in relation to multinuclear aromatic hydrocarbons.
{"title":"Sampling and concentration of polycyclic aromatic hydrocarbons from exhaust gases from a plant for synthesis of carbon nanomaterials","authors":"S. M. Leschev, T. Henarava","doi":"10.33581/2520-257x-2021-2-62-73","DOIUrl":"https://doi.org/10.33581/2520-257x-2021-2-62-73","url":null,"abstract":"Currently, there is an increase in the production of carbon nanomaterials in the world, which is associated with their unique physical and mechanical properties and their use in various fields of science, industry and technology. Investigation of the chemical composition of waste gases from a propane-butane mixture pyrolysis unit during the synthesis of carbon nanomaterials is of scientific and applied value, since it allows one to study both the chemistry of the pyrolysis process of hydrocarbon mixtures and determine the degree of toxicity of waste gas from pyrolysis units. The quantitative determination of polycyclic aromatic hydrocarbons in the gaseous products of pyrolysis of a propane-butane mixture during the synthesis of carbon nanomaterials has shown that when sampling with a small amount of the Supelpak-2 adsorbent, which is widely used in international and domestic methods, efficient capture of multinuclear aromatic hydrocarbons is not ensured. Therefore, an important research issue is the development of a simple and effective method for sampling polycyclic aromatic hydrocarbons with their subsequent GC-MS analysis. The principal essence of the technique is the impregnation of two fiberglass filters with an organic low-volatile solvent – diethylene glycol, tetraethylene glycol or dimethyl sulfoxide. The latter is characterised by the highest extracting power in relation to polycyclic aromatic hydrocarbons. The developed technique makes it possible to increase the efficiency of capturing multinuclear aromatic hydrocarbons (with four or more rings in a molecule) to 96–98 % compared to a solid adsorbent under equal conditions (pyrolysis conditions, weight of adsorbent equal with filters impregnated with a solvent), where the degree of their extraction is 1–5 %. The established values of the degree of recovery of the measured components are explained by the high extracting ability of dimethyl sulfoxide in relation to multinuclear aromatic hydrocarbons.","PeriodicalId":17303,"journal":{"name":"Journal of the Belarusian State University. Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88190669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-22DOI: 10.33581/2520-257x-2021-2-17-24
Ekaterina G. Ragoyja, V. Matulis, O. Ivashkevich
It was shown that N2O content among NO reduction products increases with an increase of the silver concentration in the catalyst because the nature of the catalytic centers changes and leads to a subsequent change in the mechanism of the reaction. Two reaction mechanisms were proposed and studied by means of quantum chemistry: a two-stage mechanism that proceeds via NO dimer formation on catalysts with high (above 2 wt. %) silver concentration and a parallel mechanism with isocyanates involved on catalysts with low (below 2 wt. %) silver concentration. It was demonstrated that on catalysts with high silver concentration mechanism that involves stepwise NO reduction via N2O to N2 is realised. Moreover, the final stage is complicated by the fact that formed intermediates and N2O are likely to desorb from the catalyst surface. In the case of catalysts with low silver concentration, the formation of both products (N2O and N2) proceeds in parallel and the lower activation barriers of the reaction leading to N2, as well as the thermodynamic profitability of its formation, lead to the predominance of the target product. The competition between the proposed mechanisms was studied in the case of catalytic centers represented by silver dimers. It was shown that activation barriers of reaction proceeding via NO dimer formation are lower than the corresponding barriers of the reaction with isocyanates involved, which confirms the prevalent realisation of the first process and the predominance of N2O among the final products. The obtained results explain the experimental data and are significant for further modelling of the mechanism of nitrogen oxides catalytic reduction considering the Al2O3 support.
{"title":"Quantum chemical study of NO reduction mechanism on Ag /Al2O3 catalysts","authors":"Ekaterina G. Ragoyja, V. Matulis, O. Ivashkevich","doi":"10.33581/2520-257x-2021-2-17-24","DOIUrl":"https://doi.org/10.33581/2520-257x-2021-2-17-24","url":null,"abstract":"It was shown that N2O content among NO reduction products increases with an increase of the silver concentration in the catalyst because the nature of the catalytic centers changes and leads to a subsequent change in the mechanism of the reaction. Two reaction mechanisms were proposed and studied by means of quantum chemistry: a two-stage mechanism that proceeds via NO dimer formation on catalysts with high (above 2 wt. %) silver concentration and a parallel mechanism with isocyanates involved on catalysts with low (below 2 wt. %) silver concentration. It was demonstrated that on catalysts with high silver concentration mechanism that involves stepwise NO reduction via N2O to N2 is realised. Moreover, the final stage is complicated by the fact that formed intermediates and N2O are likely to desorb from the catalyst surface. In the case of catalysts with low silver concentration, the formation of both products (N2O and N2) proceeds in parallel and the lower activation barriers of the reaction leading to N2, as well as the thermodynamic profitability of its formation, lead to the predominance of the target product. The competition between the proposed mechanisms was studied in the case of catalytic centers represented by silver dimers. It was shown that activation barriers of reaction proceeding via NO dimer formation are lower than the corresponding barriers of the reaction with isocyanates involved, which confirms the prevalent realisation of the first process and the predominance of N2O among the final products. The obtained results explain the experimental data and are significant for further modelling of the mechanism of nitrogen oxides catalytic reduction considering the Al2O3 support.","PeriodicalId":17303,"journal":{"name":"Journal of the Belarusian State University. Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73076591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-09-22DOI: 10.33581/2520-257x-2021-2-50-61
Natalia Apanasevich, K. Lapko, Alexander N. Kudlash, A. Sokal, Yury D. Kliaulin, K. Vishnevskii
Thermostable composite materials based on solid magnesium phosphate and calcium phosphate, as well as hybrid calcium magnesium phosphate binders have been developed and investigated. Thermal and phase transformations of the phosphate composites have been studied. Strength characteristics of composite materials have been determined in the temperature range of 20–1000 °C. It is shown that the obtained phosphate composites have high strength properties (compressive strength reaches 120–130 MPa) and are characterised by high thermal stability in the temperature range up to 1000 °С. The low weight loss of the studied composites (no more than 10 %) and the absence of significant thermal effects indicate that they are promising for use as a thermostable matrix for obtaining functional composite materials.
{"title":"Preparation and study of thermostable composites based on solid magnesium phosphate and calcium phosphate binders","authors":"Natalia Apanasevich, K. Lapko, Alexander N. Kudlash, A. Sokal, Yury D. Kliaulin, K. Vishnevskii","doi":"10.33581/2520-257x-2021-2-50-61","DOIUrl":"https://doi.org/10.33581/2520-257x-2021-2-50-61","url":null,"abstract":"Thermostable composite materials based on solid magnesium phosphate and calcium phosphate, as well as hybrid calcium magnesium phosphate binders have been developed and investigated. Thermal and phase transformations of the phosphate composites have been studied. Strength characteristics of composite materials have been determined in the temperature range of 20–1000 °C. It is shown that the obtained phosphate composites have high strength properties (compressive strength reaches 120–130 MPa) and are characterised by high thermal stability in the temperature range up to 1000 °С. The low weight loss of the studied composites (no more than 10 %) and the absence of significant thermal effects indicate that they are promising for use as a thermostable matrix for obtaining functional composite materials.","PeriodicalId":17303,"journal":{"name":"Journal of the Belarusian State University. Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75353614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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