Pub Date : 2024-08-21DOI: 10.1134/s1070427223120030
M. A. Zotkin, D. A. Alentiev, S. E. Sokolov, M. V. Bermeshev
Abstract
Sorption of carbon dioxide, methane, and hydrogen in additive poly(5-norbornyl-2-norbornene) was studied at pressures in the interval 0–10 bar and temperatures in the interval 10–60°C. The isotherms obtained were described by the double sorption model including both Langmuir and Henry sorption models. The double sorption model parameters and the gas solFigubility coefficients in the polymer at different pressures and at infinite dilutions were determined. The solubility selectivity values were calculated from the data obtained. The highest solubility selectivity for the CO2/CH4 gas pair is reached at 20°С. Owing to high values of this selectivity, additive poly(5-norbornyl-2-norbornene) can be considered as a candidate membrane material for the separation of gas mixtures containing CO2.
{"title":"Sorption of Gases in Additive Polynorbornene with Norbornyl Substituents","authors":"M. A. Zotkin, D. A. Alentiev, S. E. Sokolov, M. V. Bermeshev","doi":"10.1134/s1070427223120030","DOIUrl":"https://doi.org/10.1134/s1070427223120030","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Sorption of carbon dioxide, methane, and hydrogen in additive poly(5-norbornyl-2-norbornene) was studied at pressures in the interval 0–10 bar and temperatures in the interval 10–60°C. The isotherms obtained were described by the double sorption model including both Langmuir and Henry sorption models. The double sorption model parameters and the gas solFigubility coefficients in the polymer at different pressures and at infinite dilutions were determined. The solubility selectivity values were calculated from the data obtained. The highest solubility selectivity for the CO<sub>2</sub>/CH<sub>4</sub> gas pair is reached at 20°С. Owing to high values of this selectivity, additive poly(5-norbornyl-2-norbornene) can be considered as a candidate membrane material for the separation of gas mixtures containing CO<sub>2</sub>.</p>","PeriodicalId":757,"journal":{"name":"Russian Journal of Applied Chemistry","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142186404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-21DOI: 10.1134/s1070427223120078
G. V. Tsaplin, S. A. Kazakov, M. I. Semchukova, E. A. Alekseeva, A. L. Alekseenko, I. M. Chernega, S. V. Popkov
Abstract
A procedure was developed for preparing 2-alkylthio-5-(1,2,4-triazol-1-ylmethyl)-1,3,4-oxadiazoles by alkylation of 5-(1Н-1,2,4-triazol-1-ylmethyl)-1,3,4-oxadiazole-2-thione with β-bromophenetoles in the presence of triethylamine in acetone with up to 90% yield. The in vitro tests of the target compounds for fungicidal activity toward six species of phytopathogenic fungi of different taxonomic classes show that the S-halophenoxyethyl-substituted derivatives surpass a reference fungicide, Triadimefon, in the activity toward Venturia inaequalis, Rhizoctonia solani, and Bipolaris sorokiniana.
{"title":"Design, Synthesis, and Fungicidal Activity of 2-Alkylthio-5-(1,2,4-triazol-1-ylmethyl)-1,3,4-oxadiazoles","authors":"G. V. Tsaplin, S. A. Kazakov, M. I. Semchukova, E. A. Alekseeva, A. L. Alekseenko, I. M. Chernega, S. V. Popkov","doi":"10.1134/s1070427223120078","DOIUrl":"https://doi.org/10.1134/s1070427223120078","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>A procedure was developed for preparing 2-alkylthio-5-(1,2,4-triazol-1-ylmethyl)-1,3,4-oxadiazoles by alkylation of 5-(1<i>Н-</i>1,2,4-triazol-1-ylmethyl)-1,3,4-oxadiazole-2-thione with β-bromophenetoles in the presence of triethylamine in acetone with up to 90% yield. The <i>in vitro</i> tests of the target compounds for fungicidal activity toward six species of phytopathogenic fungi of different taxonomic classes show that the S-halophenoxyethyl-substituted derivatives surpass a reference fungicide, Triadimefon, in the activity toward <i>Venturia inaequalis</i>, <i>Rhizoctonia solani</i>, and <i>Bipolaris sorokiniana</i>.</p>","PeriodicalId":757,"journal":{"name":"Russian Journal of Applied Chemistry","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224541","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-21DOI: 10.1134/s1070427223120054
M. G. Mukhamediev, D. A. Gafurova, D. Zh. Bekchanov, D. N. Shakhidova, T. Kh. Rakhimov
Abstract
The physicochemical features of the solubilization of gossypol (GS) with polyivinylpyrrolidone (PVP) were studied. In contrast to the initial polyphenol, the solubilization product is a water-soluble supramolecular complex. As shown by IR spectroscopy, the complexation of PVP with GS occurs via hydrogen bonding between the carbonyl oxygen atom of the pyrrolidone ring of the polymer and hydroxyl proton of polyphenol. The relative viscosity of aqueous solutions of the supramolecular complex depends on its composition and passes through a minimum with the lowest value of the PVP : GS ratio close to 2 : 1. That is, at this component ratio, the structure of the complex in an aqueous medium is the most compact. The GS solubilization with PVP can be presented as adsorption of the polyphenol onto the polymer and can be described by the Langmuir monomolecular adsorption theory.
{"title":"Solubilization of Gossypol with Polyvinylpyrrolidone","authors":"M. G. Mukhamediev, D. A. Gafurova, D. Zh. Bekchanov, D. N. Shakhidova, T. Kh. Rakhimov","doi":"10.1134/s1070427223120054","DOIUrl":"https://doi.org/10.1134/s1070427223120054","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The physicochemical features of the solubilization of gossypol (GS) with polyivinylpyrrolidone (PVP) were studied. In contrast to the initial polyphenol, the solubilization product is a water-soluble supramolecular complex. As shown by IR spectroscopy, the complexation of PVP with GS occurs via hydrogen bonding between the carbonyl oxygen atom of the pyrrolidone ring of the polymer and hydroxyl proton of polyphenol. The relative viscosity of aqueous solutions of the supramolecular complex depends on its composition and passes through a minimum with the lowest value of the PVP : GS ratio close to 2 : 1. That is, at this component ratio, the structure of the complex in an aqueous medium is the most compact. The GS solubilization with PVP can be presented as adsorption of the polyphenol onto the polymer and can be described by the Langmuir monomolecular adsorption theory.</p>","PeriodicalId":757,"journal":{"name":"Russian Journal of Applied Chemistry","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-21DOI: 10.1134/s107042722312008x
E. K. Grachev, A. S. Buinovsky, A. V. Muslimova, V. M. Ilekis, E. Yu. Kartashov, M. S. Syrtanov, M. A. Kruglyakov, V. I. Sachkov
Abstract
The hydrogen decrepitation of end-of-life NdFeB magnetic alloys was studied. End-of-life magnets extracted from PC hard drives were taken as a material for the experiments. The choice of these items is governed by their low cost, easy removal from PC, and small size. The magnets were demagnetized at 623 K in a medium vacuum for 4 h, which was followed by three-step cleaning of their surface to remove the electroplated coating, oxidized surface layer, and adsorbed impurities and moisture. The first step of the cleaning was sandblasting with slag shot fed at a pressure of 300 kPa. The second step was chemical etching with solutions of dilute acids (1–3% HCl, HNO3, or H2SO4 in distilled water), followed by washing in acetone. The third step was heat treatment in a vacuum, consisting in rapid heating in a shaft furnace of magnet samples placed after etching in an autoclave, with several exposures in the temperature interval 373–573 K in a medium vacuum. After these operations, the samples were quenched by placing the hot autoclave into a vessel with ice-cold water, preceded by filling the autoclave with argon. Then, alloys of the NdFeB system without removing from the autoclave were subjected to hydrogen decrepitation performed in the temperature interval from 298 to 473 K at an excess hydrogen pressure of 30 to 210 kPa to determine how these parameters influence the properties of the hydride powders obtained and the amount of hydrogen taken up. The hydrogen for the decrepitation was generated by direct desorption from the heated hydride of the LaNi5 alloy. In the pressure range 30–70 kPa and room temperature, alloys of the NdFeB system transform into hydrides. The chemical reaction with hydrogen starts instantaneously without a period of primary hydrogen adsorption. The hydride powders obtained, containing no less than 0.459 wt % hydrogen, are very brittle and can be finely milled (100-g portion) in a planetary ball mill within 6 min to obtain a powder with the particle size smaller than 20 μm. The analysis of the surface of the finely milled hydride powder particles revealed no oxygen (≤1 wt %).
摘要 研究了报废钕铁硼磁性合金的氢衰变。实验材料是从 PC 硬盘驱动器中提取的报废磁铁。之所以选择这些材料，是因为它们成本低、易于从 PC 中取出且体积小。磁铁在 623 K 中真空条件下消磁 4 小时，然后分三步清洁磁铁表面，以去除电镀涂层、氧化表面层以及吸附的杂质和水分。清洗的第一步是用压力为 300 kPa 的熔渣喷丸进行喷砂。第二步是用稀酸溶液（蒸馏水中 1-3%的 HCl、HNO3 或 H2SO4）进行化学蚀刻，然后用丙酮清洗。第三步是在真空中进行热处理，包括将蚀刻后的磁体样品放入高压釜中的竖炉中快速加热，并在中等真空中的 373-573 K 温度区间内进行多次曝露。在这些操作之后，将热的高压釜放入装有冰水的容器中，然后在高压釜中注入氩气，使样品骤冷。然后，在不从高压釜中取出钕铁硼系统合金的情况下，在 298 至 473 K 的温度区间和 30 至 210 kPa 的过量氢气压力下进行氢气降解，以确定这些参数如何影响所获得的氢化物粉末的特性和所吸收的氢气量。用于降解的氢气是从加热的 LaNi5 合金氢化物中直接解吸产生的。在 30-70 kPa 的压力范围和室温下，钕铁硼系统的合金会转化为氢化物。与氢的化学反应瞬间开始，没有初级氢吸附期。获得的氢化物粉末含氢量不低于 0.459 wt %，非常脆，可以在行星球磨机中在 6 分钟内进行细磨（100 克份），获得粒度小于 20 μm 的粉末。对精细研磨的氢化物粉末颗粒表面的分析表明没有氧气（≤1 wt %）。
{"title":"Hydrogen Decrepitation of NdFeB End-of-Life Magnets with the Preliminary Three-Step Surface Cleaning","authors":"E. K. Grachev, A. S. Buinovsky, A. V. Muslimova, V. M. Ilekis, E. Yu. Kartashov, M. S. Syrtanov, M. A. Kruglyakov, V. I. Sachkov","doi":"10.1134/s107042722312008x","DOIUrl":"https://doi.org/10.1134/s107042722312008x","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The hydrogen decrepitation of end-of-life NdFeB magnetic alloys was studied. End-of-life magnets extracted from PC hard drives were taken as a material for the experiments. The choice of these items is governed by their low cost, easy removal from PC, and small size. The magnets were demagnetized at 623 K in a medium vacuum for 4 h, which was followed by three-step cleaning of their surface to remove the electroplated coating, oxidized surface layer, and adsorbed impurities and moisture. The first step of the cleaning was sandblasting with slag shot fed at a pressure of 300 kPa. The second step was chemical etching with solutions of dilute acids (1–3% HCl, HNO<sub>3</sub>, or H<sub>2</sub>SO<sub>4</sub> in distilled water), followed by washing in acetone. The third step was heat treatment in a vacuum, consisting in rapid heating in a shaft furnace of magnet samples placed after etching in an autoclave, with several exposures in the temperature interval 373–573 K in a medium vacuum. After these operations, the samples were quenched by placing the hot autoclave into a vessel with ice-cold water, preceded by filling the autoclave with argon. Then, alloys of the NdFeB system without removing from the autoclave were subjected to hydrogen decrepitation performed in the temperature interval from 298 to 473 K at an excess hydrogen pressure of 30 to 210 kPa to determine how these parameters influence the properties of the hydride powders obtained and the amount of hydrogen taken up. The hydrogen for the decrepitation was generated by direct desorption from the heated hydride of the LaNi<sub>5</sub> alloy. In the pressure range 30–70 kPa and room temperature, alloys of the NdFeB system transform into hydrides. The chemical reaction with hydrogen starts instantaneously without a period of primary hydrogen adsorption. The hydride powders obtained, containing no less than 0.459 wt % hydrogen, are very brittle and can be finely milled (100-g portion) in a planetary ball mill within 6 min to obtain a powder with the particle size smaller than 20 μm. The analysis of the surface of the finely milled hydride powder particles revealed no oxygen (≤1 wt %).</p>","PeriodicalId":757,"journal":{"name":"Russian Journal of Applied Chemistry","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142186429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-21DOI: 10.1134/s1070427223120042
E. I. Medentseva, A. P. Khrychikova, E. V. Bermesheva, K. V. Potapov, M. V. Bermeshev
Abstract
Addition polymerization of 3-methyl-3-phenylcyclopropene and 3,3-di(n-propyl)cyclopropene in the presence of a palladium complex containing an acyclic diaminocarbene ligand was studied. When activated with the organoborate (Na+[B(3,5-(CF3)2C6H3)4]–), such complex catalyzes the addition polymerization of substituted cyclopropenes. The polymerization occurs selectively without opening of the cyclopropane ring. The copolymerization of 3,3-di(n-propyl)cyclopropene with a monomer of the norbornene series (5-ethylidene-2-norbornene) was monitored by a decrease in the intensity of the characteristic signals in the 1H NMR spectra of the corresponding monomers. The substituted cyclopropenes were found to be more active monomers than norbornenes in the addition polymerization. The addition homopolymers of 3-methyl-3-phenylcyclopropene and 3,3-di(n-propyl)cyclopropene were characterized by differential scanning calorimetry, thermogravimetric analysis, and X-ray diffraction.
{"title":"Addition Polymerization of 3,3-Disubstituted Cyclopropenes in the Presence of a Palladium Complex Containing an Acyclic Diaminocarbene Ligand","authors":"E. I. Medentseva, A. P. Khrychikova, E. V. Bermesheva, K. V. Potapov, M. V. Bermeshev","doi":"10.1134/s1070427223120042","DOIUrl":"https://doi.org/10.1134/s1070427223120042","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Addition polymerization of 3-methyl-3-phenylcyclopropene and 3,3-di(<i>n</i>-propyl)cyclopropene in the presence of a palladium complex containing an acyclic diaminocarbene ligand was studied. When activated with the organoborate (Na<sup>+</sup>[B(3,5-(CF<sub>3</sub>)<sub>2</sub>C<sub>6</sub>H<sub>3</sub>)<sub>4</sub>]<sup>–</sup>), such complex catalyzes the addition polymerization of substituted cyclopropenes. The polymerization occurs selectively without opening of the cyclopropane ring. The copolymerization of 3,3-di(<i>n</i>-propyl)cyclopropene with a monomer of the norbornene series (5-ethylidene-2-norbornene) was monitored by a decrease in the intensity of the characteristic signals in the <sup>1</sup>H NMR spectra of the corresponding monomers. The substituted cyclopropenes were found to be more active monomers than norbornenes in the addition polymerization. The addition homopolymers of 3-methyl-3-phenylcyclopropene and 3,3-di(<i>n</i>-propyl)cyclopropene were characterized by differential scanning calorimetry, thermogravimetric analysis, and X-ray diffraction.</p>","PeriodicalId":757,"journal":{"name":"Russian Journal of Applied Chemistry","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142224539","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-21DOI: 10.1134/s1070427223120029
I. Yu. Kaplin, E. V. Golubina, A. V. Gorodnova, E. S. Lokteva, M. A. Galkin, A. V. Fionov, O. Ya. Isaikina, A. V. Shumyantsev, K. I. Maslakov
Abstract
The effect that introduction of cerium oxide into oxide systems based on chromium and silicon exerts on the catalytic properties of these systems in nonoxidative propane dehydrogenation in a flow-through system with a fixed catalyst bed was studied. The characteristics of the catalysts CrOx–SiO2 and CrOx–CeO2–SiO2, both containing 9 wt % CrOx assuming the Cr2O3 stoichiometry, were compared. The СеО2 content of the ternary system was 52 wt %. The catalysts were characterized by X-ray diffraction analysis, scanning electron microscopy, Raman spectroscopy, electron paramagnetic resonance, X-ray photoelectron spectroscopy, temperature-programmed reduction with hydrogen, and thermal analysis. In the initial period of the reaction, the catalyst containing CeO2 demonstrated higher propane conversion at 500 and 550°С and higher deactivation rate compared to CrOx–SiO2. Both catalysts can be regenerated by treatment in an air stream at 550°С for 30 min. Cerium dioxide favors the reduction of chromium in high oxidation states to form active reaction sites, Cr3+ ions, ensures higher dispersity of the chromium oxides, and favors partial oxidation of coke deposits in the initial period of the catalyst operation.
{"title":"CrOx–SiO2 Catalysts in Nonoxidative Propane Dehydrogenation: Effect of Adding Cerium Dioxide","authors":"I. Yu. Kaplin, E. V. Golubina, A. V. Gorodnova, E. S. Lokteva, M. A. Galkin, A. V. Fionov, O. Ya. Isaikina, A. V. Shumyantsev, K. I. Maslakov","doi":"10.1134/s1070427223120029","DOIUrl":"https://doi.org/10.1134/s1070427223120029","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The effect that introduction of cerium oxide into oxide systems based on chromium and silicon exerts on the catalytic properties of these systems in nonoxidative propane dehydrogenation in a flow-through system with a fixed catalyst bed was studied. The characteristics of the catalysts CrO<sub>x</sub>–SiO<sub>2</sub> and CrO<sub>x</sub>–CeO<sub>2</sub>–SiO<sub>2</sub>, both containing 9 wt % CrO<sub>x</sub> assuming the Cr<sub>2</sub>O<sub>3</sub> stoichiometry, were compared. The СеО<sub>2</sub> content of the ternary system was 52 wt %. The catalysts were characterized by X-ray diffraction analysis, scanning electron microscopy, Raman spectroscopy, electron paramagnetic resonance, X-ray photoelectron spectroscopy, temperature-programmed reduction with hydrogen, and thermal analysis. In the initial period of the reaction, the catalyst containing CeO<sub>2</sub> demonstrated higher propane conversion at 500 and 550°С and higher deactivation rate compared to CrO<sub>x</sub>–SiO<sub>2</sub>. Both catalysts can be regenerated by treatment in an air stream at 550°С for 30 min. Cerium dioxide favors the reduction of chromium in high oxidation states to form active reaction sites, Cr<sup>3+</sup> ions, ensures higher dispersity of the chromium oxides, and favors partial oxidation of coke deposits in the initial period of the catalyst operation.</p>","PeriodicalId":757,"journal":{"name":"Russian Journal of Applied Chemistry","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142186428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-21DOI: 10.1134/s1070427223120017
E. M. Zakharyan, A. L. Maksimov
Abstract
The need for polyethylene terephthalate recycling is associated with the formation of significant amount of its waste, which should be reprocessed due to the growth of polymer production and consumption of plastic products used in light, chemical, medical industries, in mechanical engineering and instrument making. The main share of polyethylene terephthalate (PET) recycling processes is chemical methods through which various monomers are generated. After purification and modification of these monomers, valuable petrochemical raw materials can be yielded. The review describes the principles and mechanisms of polyethylene terephthalate degradation upon pyrolysis. The influence of the heating rate during pyrolysis (fast, slow), type of raw material (pure polymer, polymer waste), additives (modifiers, stabilizers, fire retardants), type of reactor in the process (horizontal, vertical, fixed bed reactor, fluidized bed reactor, conical tip reactor, rotating dc arc plasma reactor) is considered, as well as the effect of processing conditions such as temperature, amount of raw material, pressure, atmosphere, and presence of catalyst on the quantitative and qualitative composition of oxygen-containing compounds formed in the gas fraction, pyrolysis oil, and semi-coke. The influence of additives of various polymers in a mixture with polyethylene terephthalate on the formation of products (gas fraction, pyrolysis oil, and semi-coke), additives of plant biomass, and food waste is demonstrated. The effect of microwave radiation on the polyethylene terephthalate pyrolysis is considered.
{"title":"Pyrolysis of Polyethylene Terephthalate: Process Features and Composition of Reaction Products","authors":"E. M. Zakharyan, A. L. Maksimov","doi":"10.1134/s1070427223120017","DOIUrl":"https://doi.org/10.1134/s1070427223120017","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The need for polyethylene terephthalate recycling is associated with the formation of significant amount of its waste, which should be reprocessed due to the growth of polymer production and consumption of plastic products used in light, chemical, medical industries, in mechanical engineering and instrument making. The main share of polyethylene terephthalate (PET) recycling processes is chemical methods through which various monomers are generated. After purification and modification of these monomers, valuable petrochemical raw materials can be yielded. The review describes the principles and mechanisms of polyethylene terephthalate degradation upon pyrolysis. The influence of the heating rate during pyrolysis (fast, slow), type of raw material (pure polymer, polymer waste), additives (modifiers, stabilizers, fire retardants), type of reactor in the process (horizontal, vertical, fixed bed reactor, fluidized bed reactor, conical tip reactor, rotating dc arc plasma reactor) is considered, as well as the effect of processing conditions such as temperature, amount of raw material, pressure, atmosphere, and presence of catalyst on the quantitative and qualitative composition of oxygen-containing compounds formed in the gas fraction, pyrolysis oil, and semi-coke. The influence of additives of various polymers in a mixture with polyethylene terephthalate on the formation of products (gas fraction, pyrolysis oil, and semi-coke), additives of plant biomass, and food waste is demonstrated. The effect of microwave radiation on the polyethylene terephthalate pyrolysis is considered.</p>","PeriodicalId":757,"journal":{"name":"Russian Journal of Applied Chemistry","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142186426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-21DOI: 10.1134/s1070427223120066
T. P. Bekezina, M. S. Vaisbekker, V. A. Burmistrova, V. G. Bozhkov
Abstract
The nature of cathodic polarization in an iridium-plating electrolyte based on a sulfamate solution of H2[IrCl6] was studied. Spectroscopic analysis shows that the iridium electrolyte contains binuclear oxygen-bridged Ir(III, IV) sulfamate complexes. The microstructure and distribution profiles of the iridium deposit in contacts of different diameters were studied. The structure of the iridium deposit is highly dispersed. The nonuniformity of the iridium deposit profile over the contact area and the dependence of the deposit thickness on the contact diameter can be reduced by varying the hydrodynamic conditions of the metal electroplating (stirring of the electrolyte with a magnetic stirrer or ultrasound) and by using electrochemical polarization. The Ir–GaAs contacts with the Schottky barrier are characterized by high quality of electrophysical parameters and good reproducibility of the volt–ampere characteristics. A decrease in the thickness of the iridium deposit and of the n-GaAs epitaxial layer leads to an increase in the barrier height of the rectifying Ir–GaAs contacts.
{"title":"Electrochemical Deposition of Iridium onto Gallium Arsenide from a Sulfamate Electrolyte Based on Hexachloroiridic(IV) Acid","authors":"T. P. Bekezina, M. S. Vaisbekker, V. A. Burmistrova, V. G. Bozhkov","doi":"10.1134/s1070427223120066","DOIUrl":"https://doi.org/10.1134/s1070427223120066","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The nature of cathodic polarization in an iridium-plating electrolyte based on a sulfamate solution of H<sub>2</sub>[IrCl<sub>6</sub>] was studied. Spectroscopic analysis shows that the iridium electrolyte contains binuclear oxygen-bridged Ir(III, IV) sulfamate complexes. The microstructure and distribution profiles of the iridium deposit in contacts of different diameters were studied. The structure of the iridium deposit is highly dispersed. The nonuniformity of the iridium deposit profile over the contact area and the dependence of the deposit thickness on the contact diameter can be reduced by varying the hydrodynamic conditions of the metal electroplating (stirring of the electrolyte with a magnetic stirrer or ultrasound) and by using electrochemical polarization. The Ir–GaAs contacts with the Schottky barrier are characterized by high quality of electrophysical parameters and good reproducibility of the volt–ampere characteristics. A decrease in the thickness of the iridium deposit and of the n-GaAs epitaxial layer leads to an increase in the barrier height of the rectifying Ir–GaAs contacts.</p>","PeriodicalId":757,"journal":{"name":"Russian Journal of Applied Chemistry","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142186427","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-20DOI: 10.1134/s1070427224020125
Y. F. El-Aryan, S. Melhi
Abstract
Polyacrylonitrile chromium(III) molybdate composite has been synthesized by mixing polyacrylonitrile into inorganic material chromium molybdate. The physicochemical properties of this material were determined using X-ray diffractometer system (XRD), infrared (IR) and thermal analysis (TGA and DTA). The adsorption studies were carried out under various parameters, such as pH, adsorbent dosage, contact time, and initial dye concentration. The experimental results show that the percentage of adsorption increases with an increase in the adsorbent dosage. The maximum adsorption occurred at the pH value of 2.45 The equilibrium uptake was increased with an increase in the initial dye concentration in solution. Adsorption kinetic data were properly fitted with the pseudo-second-order kinetic model. The experimental isotherms data were analyzed using Langmuir and Freundlich isotherm equations. The best fit was obtained by the Langmuir model with high correlation coefficients (R2 = 0.9976) with a maximum monolayer adsorption capacity of 11.38 mg/g.
{"title":"Adsorption Study of Eriochrome Black T Dye on Polyacrylonitrile Chromium molybdate Composite","authors":"Y. F. El-Aryan, S. Melhi","doi":"10.1134/s1070427224020125","DOIUrl":"https://doi.org/10.1134/s1070427224020125","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Polyacrylonitrile chromium(III) molybdate composite has been synthesized by mixing polyacrylonitrile into inorganic material chromium molybdate. The physicochemical properties of this material were determined using X-ray diffractometer system (XRD), infrared (IR) and thermal analysis (TGA and DTA). The adsorption studies were carried out under various parameters, such as pH, adsorbent dosage, contact time, and initial dye concentration. The experimental results show that the percentage of adsorption increases with an increase in the adsorbent dosage. The maximum adsorption occurred at the pH value of 2.45 The equilibrium uptake was increased with an increase in the initial dye concentration in solution. Adsorption kinetic data were properly fitted with the pseudo-second-order kinetic model. The experimental isotherms data were analyzed using Langmuir and Freundlich isotherm equations. The best fit was obtained by the Langmuir model with high correlation coefficients (<i>R</i><sup>2</sup> = 0.9976) with a maximum monolayer adsorption capacity of 11.38 mg/g.</p>","PeriodicalId":757,"journal":{"name":"Russian Journal of Applied Chemistry","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142186430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-20DOI: 10.1134/s1070427224020137
Mahsa Rahimi Sadr, Biuck Habibi, Naser Samadi
Abstract
Mercury metal ions are very toxic, the presence of this metal and its derivatives, which are harmful even in very small amounts to the health of all organisms, was found in the study area. The purpose of this study is determination and elimination of Hg (II) ions from drinking water and aqueous environments. Modified and activated carbon produced from local plantain bark has been considered to be suitable and environmentally friendly material for mercury (II) ions removal in water treatments. 85% phosphoric acid chemical activator was used, It is then heated to 450°C for 5 h to carry out carbonization. The absorbent was characterized by SEM. Removal was performed by passing water containing ions through a column containing the adsorbent The prepared adsorbent well removed mercury ions from the aqueous solution, measuring of concentration mercury ions in samples from the inlet and outlet of the column was performed by two different methods, spectrophotometric determination at 492 nm with dithizone and atomic absorption (equipped with cold vaper apparatus) spectroscopy CVAAS, the results were almost the same. The various parameters such as pH, with (6–8), contact time (0.5, 1, 2, and 3 h), concentrations of metal ions entering the system (0.25, 0.5, 0.75, and 1 ppm), and agitation speed were investigated on adsorption effect. The efficiency of this absorbent for removal of Hg (II) ions is 87%. It can be used several times, which shows that this is a good adsorbent for elimination of mercury ions of real samples such as drinking water and industrial wastewaters, due to its ease of use, low cost and relatively good performance. The elimination method is simple, sensitive, inexpensive, fast, usable and vital for the peoples in this area
{"title":"Optimization and Characterization of a New Environmentally Friendly Adsorbent to Remove Mercury Ions from Aqueous Solutions","authors":"Mahsa Rahimi Sadr, Biuck Habibi, Naser Samadi","doi":"10.1134/s1070427224020137","DOIUrl":"https://doi.org/10.1134/s1070427224020137","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Mercury metal ions are very toxic, the presence of this metal and its derivatives, which are harmful even in very small amounts to the health of all organisms, was found in the study area. The purpose of this study is determination and elimination of Hg (II) ions from drinking water and aqueous environments. Modified and activated carbon produced from local plantain bark has been considered to be suitable and environmentally friendly material for mercury (II) ions removal in water treatments. 85% phosphoric acid chemical activator was used, It is then heated to 450°C for 5 h to carry out carbonization. The absorbent was characterized by SEM. Removal was performed by passing water containing ions through a column containing the adsorbent The prepared adsorbent well removed mercury ions from the aqueous solution, measuring of concentration mercury ions in samples from the inlet and outlet of the column was performed by two different methods, spectrophotometric determination at 492 nm with dithizone and atomic absorption (equipped with cold vaper apparatus) spectroscopy CVAAS, the results were almost the same. The various parameters such as pH, with (6–8), contact time (0.5, 1, 2, and 3 h), concentrations of metal ions entering the system (0.25, 0.5, 0.75, and 1 ppm), and agitation speed were investigated on adsorption effect. The efficiency of this absorbent for removal of Hg (II) ions is 87%. It can be used several times, which shows that this is a good adsorbent for elimination of mercury ions of real samples such as drinking water and industrial wastewaters, due to its ease of use, low cost and relatively good performance. The elimination method is simple, sensitive, inexpensive, fast, usable and vital for the peoples in this area</p>","PeriodicalId":757,"journal":{"name":"Russian Journal of Applied Chemistry","volume":null,"pages":null},"PeriodicalIF":0.9,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142186432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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