Pub Date : 2024-09-04DOI: 10.1134/s0023158424601736
D. A. Bokarev, I. V. Paramoshin, S. A. Kanaev, G. N. Baeva, A. V. Rassolov, A. Yu. Stakheev
Abstract
The Co/BEA zeolite catalyst was found to exhibit exceptionally high activity in ozone catalytic oxidation (OZCO) of methane impurities in air, and it provided CH4 conversion >85% in the temperature range 90–170°С at a high gas hourly space velocity (100 000 h–1). A comparative study of the catalytic performance of 0.5% Co/BEA, 5% Co/BEA, and 5% Co/SiO2 samples was performed for elucidating the nature of the active sites on which the process takes place. The comparison of the catalytic data with the results of catalyst characterization by electron microscopy, UV spectroscopy, X-ray diffraction analysis, and temperature-programmed reduction allowed us to conclude that the active sites of low-temperature methane oxidation are Co2+ ions located in the cationic positions of the zeolite framework, and the 0.5% Co/BEA catalyst had the highest activity in methane oxidation.
{"title":"Low-Temperature O3-Catalytic Oxidation of Methane on Cobalt-Containing Zeolite Catalysts","authors":"D. A. Bokarev, I. V. Paramoshin, S. A. Kanaev, G. N. Baeva, A. V. Rassolov, A. Yu. Stakheev","doi":"10.1134/s0023158424601736","DOIUrl":"https://doi.org/10.1134/s0023158424601736","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The Co/BEA zeolite catalyst was found to exhibit exceptionally high activity in ozone catalytic oxidation (OZCO) of methane impurities in air, and it provided CH<sub>4</sub> conversion >85% in the temperature range 90–170°С at a high gas hourly space velocity (100 000 h<sup>–1</sup>). A comparative study of the catalytic performance of 0.5% Co/BEA, 5% Co/BEA, and 5% Co/SiO<sub>2</sub> samples was performed for elucidating the nature of the active sites on which the process takes place. The comparison of the catalytic data with the results of catalyst characterization by electron microscopy, UV spectroscopy, X-ray diffraction analysis, and temperature-programmed reduction allowed us to conclude that the active sites of low-temperature methane oxidation are Co<sup>2+</sup> ions located in the cationic positions of the zeolite framework, and the 0.5% Co/BEA catalyst had the highest activity in methane oxidation.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200012","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 : 2024-09-04DOI: 10.1134/s0023158424601700
T. V. Krasnyakova, D. V. Nikitenko, A. A. Gusev, V. G. But’ko, S. A. Mitchenko
Abstract
The energy profile for vinyl iodide (RI) electrophile C(sp2)–C(sp2) homocoupling catalyzed by platinum(II) iodo complexes has been theoretically evaluated by the DFT method using the hybrid meta exchange-correlation functional M06 and the LANL2DZ basis set in the Gaussian09 software package. The reaction mechanism proposed earlier on the basis of experimental data was confirmed, consisting of the sequence of the following steps: RI oxidative addition to PtII to form the intermediate compound RPtIV— reduction of the latter by iodide ions into RPtII—RI oxidative addition to form R2PtIV—reductive elimination to yield the final butadiene-1,3. The highest activation barrier was found for the oxidative addition of the second vinyl iodide molecule, which is consistent with the experimental fact that the overall catalytic reaction rate is limited by just this step.
{"title":"Vinyl Iodide Homocoupling Catalyzed by Platinum(II) Iodo Complexes: A DFT Study","authors":"T. V. Krasnyakova, D. V. Nikitenko, A. A. Gusev, V. G. But’ko, S. A. Mitchenko","doi":"10.1134/s0023158424601700","DOIUrl":"https://doi.org/10.1134/s0023158424601700","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The energy profile for vinyl iodide (RI) electrophile C(<i>sp</i><sup>2</sup>)–C(<i>sp</i><sup>2</sup>) homocoupling catalyzed by platinum(II) iodo complexes has been theoretically evaluated by the DFT method using the hybrid meta exchange-correlation functional M06 and the LANL2DZ basis set in the Gaussian09 software package. The reaction mechanism proposed earlier on the basis of experimental data was confirmed, consisting of the sequence of the following steps: R<sup>I</sup> oxidative addition to Pt<sup>II</sup> to form the intermediate compound RPt<sup>IV</sup>— reduction of the latter by iodide ions into RPt<sup>II</sup>—RI oxidative addition to form R<sub>2</sub>Pt<sup>IV</sup>—reductive elimination to yield the final butadiene-1,3. The highest activation barrier was found for the oxidative addition of the second vinyl iodide molecule, which is consistent with the experimental fact that the overall catalytic reaction rate is limited by just this step.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200009","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 : 2024-09-04DOI: 10.1134/s0023158424601670
A. V. Cherepanov, D. A. Knyazkov
Abstract
Understanding the kinetics and mechanism of formation of charged species in flames is of great importance for the development of ion-sensitive combustion control technologies. The development of predictive models involving ion-molecular reactions, however, is hampered by the lack of experimental data. The paper presents the results of our study of the spatial distribution of cations naturally occurring in a fuel-rich, non-sooting, laminar premixed ethylene/oxygen/argon flame using flame sampling molecular beam mass spectrometry. Particular attention is paid to the interpretation of the obtained mass spectra of cations, which are distorted by the influence of the sampling probe. The reliability of the proposed interpretation of the spectra is confirmed by consistency between the cationic and neutral flame structures. The study focused on cations with the general formula CxH(_{y}^{ + }) (53 < m/z < 165), actively formed in the reaction zone of the fuel-rich flame. Two main mechanisms of their formation are discussed: proton transfer from HCO+ and H3O+ (key cations of flame) to neutral intermediates whose mass is 1 amu smaller and gradual increase in the mass of ions in the reactions of lighter CxH(_{y}^{ + }) ions with neutral intermediates having high concentrations in the flame (acetylene, diacetylene, propylene, propyne, etc.).
{"title":"Mass Spectrometric Study of Cations in a Non-Sooting Ethylene Flame","authors":"A. V. Cherepanov, D. A. Knyazkov","doi":"10.1134/s0023158424601670","DOIUrl":"https://doi.org/10.1134/s0023158424601670","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Understanding the kinetics and mechanism of formation of charged species in flames is of great importance for the development of ion-sensitive combustion control technologies. The development of predictive models involving ion-molecular reactions, however, is hampered by the lack of experimental data. The paper presents the results of our study of the spatial distribution of cations naturally occurring in a fuel-rich, non-sooting, laminar premixed ethylene/oxygen/argon flame using flame sampling molecular beam mass spectrometry. Particular attention is paid to the interpretation of the obtained mass spectra of cations, which are distorted by the influence of the sampling probe. The reliability of the proposed interpretation of the spectra is confirmed by consistency between the cationic and neutral flame structures. The study focused on cations with the general formula C<sub><i>x</i></sub>H<span>(_{y}^{ + })</span> (53 < <i>m</i>/<i>z</i> < 165), actively formed in the reaction zone of the fuel-rich flame. Two main mechanisms of their formation are discussed: proton transfer from HCO<sup>+</sup> and H<sub>3</sub>O<sup>+</sup> (key cations of flame) to neutral intermediates whose mass is 1 amu smaller and gradual increase in the mass of ions in the reactions of lighter C<sub><i>x</i></sub>H<span>(_{y}^{ + })</span> ions with neutral intermediates having high concentrations in the flame (acetylene, diacetylene, propylene, propyne, etc.).</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200007","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 : 2024-09-04DOI: 10.1134/s002315842460175x
V. Yu. Bychkov, Yu. P. Tulenin, Yu. A. Gordienko, O. N. Sil’chenkova, V. N. Korchak
Abstract
The occurrence of dry reforming of methane (DRM) in a steady-state mode and partial oxidation of methane (POM) in a self-oscillating mode over a nickel foil sample and the simultaneous occurrence of these two reactions have been studied. It has been shown that during the cooccurrence of the DRM and POM reactions, a kinetic coupling of these reactions takes place; it is evident as a change in the self-oscillation period and a significant acceleration of the DRM reaction in certain phases of the self-oscillation cycle compared with the DRM rate over this Ni sample in a steady-state mode. The DRM acceleration effect is observed in a temperature range of 600–750°C. The maximum increase in the CO2 conversion value averaged over the oscillation period is a factor of 2.6 at a temperature of 700°C for a feed gas mixture composition of CH4 : CO2 = 1 : 1 + 3.5% O2. In addition, the effect of O2 concentration in a range of 0.5–3.5% on the increase in the DRM rate has been studied. An interpretation of the observed effects has been proposed.
{"title":"Kinetic Coupling of Steady-State Dry Reforming of Methane and Self-Oscillating Partial Oxidation of Methane over Nickel","authors":"V. Yu. Bychkov, Yu. P. Tulenin, Yu. A. Gordienko, O. N. Sil’chenkova, V. N. Korchak","doi":"10.1134/s002315842460175x","DOIUrl":"https://doi.org/10.1134/s002315842460175x","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The occurrence of dry reforming of methane (DRM) in a steady-state mode and partial oxidation of methane (POM) in a self-oscillating mode over a nickel foil sample and the simultaneous occurrence of these two reactions have been studied. It has been shown that during the cooccurrence of the DRM and POM reactions, a kinetic coupling of these reactions takes place; it is evident as a change in the self-oscillation period and a significant acceleration of the DRM reaction in certain phases of the self-oscillation cycle compared with the DRM rate over this Ni sample in a steady-state mode. The DRM acceleration effect is observed in a temperature range of 600–750°C. The maximum increase in the CO<sub>2</sub> conversion value averaged over the oscillation period is a factor of 2.6 at a temperature of 700°C for a feed gas mixture composition of CH<sub>4</sub> : CO<sub>2</sub> = 1 : 1 + 3.5% O<sub>2</sub>. In addition, the effect of O<sub>2</sub> concentration in a range of 0.5–3.5% on the increase in the DRM rate has been studied. An interpretation of the observed effects has been proposed.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200011","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 : 2024-09-04DOI: 10.1134/s0023158424601785
P. S. Bandurist, D. A. Pichugina
Abstract
Quantum chemical modeling of CO oxidation on the Cu12S6(PH3)8 and Cu12S6 clusters was performed in order to establish the general tendencies in the process on metal nanoclusters stabilized by ligands and to find out if the presence of a phosphine ligand is needed in the active site. The Langmuir–Hinshelwood mechanism was studied, which involves sequential oxidation of two CO molecules with oxygen. The calculated activation energies on Cu12S6(PH3)8 are lower than on Cu12S6 for all oxidation stages; therefore, the PH3 ligands have a positive effect on the catalytic properties of the copper sulfide cluster in the CO oxidation. A linear correlation was found between the energy of CO adsorption on various copper sulfide clusters and the activation energy of the oxidation stage: the lowest activation energy is observed for the cluster with a CO adsorption energy of 36 kJ/mol.
{"title":"Effect of Stabilizing Ligand on the Catalytic Properties of Copper Sulfide Nanoclusters in CO Oxidation","authors":"P. S. Bandurist, D. A. Pichugina","doi":"10.1134/s0023158424601785","DOIUrl":"https://doi.org/10.1134/s0023158424601785","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Quantum chemical modeling of CO oxidation on the Cu<sub>12</sub>S<sub>6</sub>(PH<sub>3</sub>)<sub>8</sub> and Cu<sub>12</sub>S<sub>6</sub> clusters was performed in order to establish the general tendencies in the process on metal nanoclusters stabilized by ligands and to find out if the presence of a phosphine ligand is needed in the active site. The Langmuir–Hinshelwood mechanism was studied, which involves sequential oxidation of two CO molecules with oxygen. The calculated activation energies on Cu<sub>12</sub>S<sub>6</sub>(PH<sub>3</sub>)<sub>8</sub> are lower than on Cu<sub>12</sub>S<sub>6</sub> for all oxidation stages; therefore, the PH<sub>3</sub> ligands have a positive effect on the catalytic properties of the copper sulfide cluster in the CO oxidation. A linear correlation was found between the energy of CO adsorption on various copper sulfide clusters and the activation energy of the oxidation stage: the lowest activation energy is observed for the cluster with a CO adsorption energy of 36 kJ/mol.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200015","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 : 2024-09-04DOI: 10.1134/s0023158424601657
S. V. Vasilevich, A. V. Mitrofanov
Abstract
Results of a kinetic study of the pyrolysis of woody biomass (Quercus robur) under conditions of continuous heating to a temperature of 873 K at a constant rate of 1.25, 2.5, 5, and 10 K/min have been discussed. An integral method has been used to describe the reaction mechanism and determine the macrokinetic parameters. It has been found that, from a phenomenological point of view, the averaged woody biomass pyrolysis reaction under test conditions corresponds to a three-dimensional diffusion model (1.25 K/min), a model described by the third-order reaction equation (2.5, 5 K/min), and a one-dimensional diffusion model (10 K/min). In this case, the relative standard deviation of the conversion values calculated using this equation from the test data is <11.2%. The division of the averaged reaction into three stages (first stage is completed at a temperature of 390 K; the second, at 579 K; the third, at the completion of the conversion process) leads to agreement between the calculated degree of degradation of the studied biomass samples and the test values in a range of the degree of degradation of 0–1. Although the relative standard deviation does not exceed 3.5%, the division of the averaged reaction into stages does not exclude discrepancies in the values of the determined macrokinetic parameters. It has been shown that the choice of the model that provides the best description of the wood conversion process depends on heating rate during the tests. Owing to this dependence, the macrokinetic parameter values significantly differ from each other. Taking this fact into account, it can be concluded that the selected models and calculated macrokinetic parameters are of a formal nature and cannot be thought of as physicochemical characteristics that are universal with respect to the subject of research. Discrepancies in calculations of macrokinetic parameters that are caused by the effect of heating rate can be eliminated by studying the kinetics of conversion under isothermal conditions (at a constant temperature).
摘要 讨论了在以 1.25、2.5、5 和 10 K/min 的恒定速率连续加热至 873 K 温度的条件下热解木质生物质（柞树）的动力学研究结果。采用积分法描述了反应机理并确定了宏观动力学参数。研究发现，从现象学的角度来看，试验条件下木质生物质热解反应的平均值对应于三维扩散模型（1.25 K/min）、三阶反应方程描述的模型（2.5、5 K/min）和一维扩散模型（10 K/min）。在这种情况下，使用该方程计算出的转化值与测试数据的相对标准偏差为 11.2%。将平均反应分为三个阶段（第一阶段在 390 K 的温度下完成；第二阶段在 579 K 的温度下完成；第三阶段在转化过程完成时完成）使得所研究的生物质样品的降解度计算值与降解度范围为 0-1 的测试值一致。虽然相对标准偏差不超过 3.5%，但将平均反应分为几个阶段并不能排除所测定的宏观动力学参数值之间的差异。试验表明，选择哪种模型能最好地描述木材转化过程取决于试验过程中的加热速率。由于这种依赖性，宏观动力学参数值之间存在很大差异。考虑到这一事实，可以得出结论：所选模型和计算的宏观动力学参数都是形式上的，不能被视为研究对象的通用物理化学特征。通过研究等温条件（恒温）下的转化动力学，可以消除因加热速率的影响而造成的宏观 动力学参数计算上的差异。
{"title":"A Kinetic Study of the Nonisothermal Pyrolysis of Wood","authors":"S. V. Vasilevich, A. V. Mitrofanov","doi":"10.1134/s0023158424601657","DOIUrl":"https://doi.org/10.1134/s0023158424601657","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Results of a kinetic study of the pyrolysis of woody biomass (<i>Quercus robur</i>) under conditions of continuous heating to a temperature of 873 K at a constant rate of 1.25, 2.5, 5, and 10 K/min have been discussed. An integral method has been used to describe the reaction mechanism and determine the macrokinetic parameters. It has been found that, from a phenomenological point of view, the averaged woody biomass pyrolysis reaction under test conditions corresponds to a three-dimensional diffusion model (1.25 K/min), a model described by the third-order reaction equation (2.5, 5 K/min), and a one-dimensional diffusion model (10 K/min). In this case, the relative standard deviation of the conversion values calculated using this equation from the test data is <11.2%. The division of the averaged reaction into three stages (first stage is completed at a temperature of 390 K; the second, at 579 K; the third, at the completion of the conversion process) leads to agreement between the calculated degree of degradation of the studied biomass samples and the test values in a range of the degree of degradation of 0–1. Although the relative standard deviation does not exceed 3.5%, the division of the averaged reaction into stages does not exclude discrepancies in the values of the determined macrokinetic parameters. It has been shown that the choice of the model that provides the best description of the wood conversion process depends on heating rate during the tests. Owing to this dependence, the macrokinetic parameter values significantly differ from each other. Taking this fact into account, it can be concluded that the selected models and calculated macrokinetic parameters are of a formal nature and cannot be thought of as physicochemical characteristics that are universal with respect to the subject of research. Discrepancies in calculations of macrokinetic parameters that are caused by the effect of heating rate can be eliminated by studying the kinetics of conversion under isothermal conditions (at a constant temperature).</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200008","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 : 2024-09-04DOI: 10.1134/s0023158424601773
G. B. Veselov, Yu. V. Shubin, A. A. Vedyagin
Abstract
In this work, a series of nickel-containing samples of carbon xerogels (Ni@CX) were synthesized by introducing nickel acetate into a solution of precursors (resorcinol and formaldehyde), joint polycondensation, and subsequent pyrolysis in an atmosphere of argon. The samples were tested in the selective hydrogenation reaction of 1,3-butadiene. It was shown that catalysts prepared without the addition of complexing agents contained nickel nanoparticles (4–7 nm) stabilized in a carbon matrix. The Ni@CX catalyst made it possible to achieve a selectivity of 93% for butenes at a conversion of 94% and a temperature of 200°C, while the selectivity for the formation of butenes in the presence of an impregnated reference sample was lower than 1%, although it provided a conversion of 100% already at 75°C. It was supposed that the selectivity of catalysts prepared by the joint synthesis increased due to the blockage of nonselective catalytic sites by carbon of the support.
{"title":"Hydrogenation of 1,3-Butadiene over Nickel-Containing Carbon Xerogels","authors":"G. B. Veselov, Yu. V. Shubin, A. A. Vedyagin","doi":"10.1134/s0023158424601773","DOIUrl":"https://doi.org/10.1134/s0023158424601773","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>In this work, a series of nickel-containing samples of carbon xerogels (Ni@CX) were synthesized by introducing nickel acetate into a solution of precursors (resorcinol and formaldehyde), joint polycondensation, and subsequent pyrolysis in an atmosphere of argon. The samples were tested in the selective hydrogenation reaction of 1,3-butadiene. It was shown that catalysts prepared without the addition of complexing agents contained nickel nanoparticles (4–7 nm) stabilized in a carbon matrix. The Ni@CX catalyst made it possible to achieve a selectivity of 93% for butenes at a conversion of 94% and a temperature of 200°C, while the selectivity for the formation of butenes in the presence of an impregnated reference sample was lower than 1%, although it provided a conversion of 100% already at 75°C. It was supposed that the selectivity of catalysts prepared by the joint synthesis increased due to the blockage of nonselective catalytic sites by carbon of the support.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142199912","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 : 2024-09-04DOI: 10.1134/s0023158424601748
V. A. Matyshak, O. N. Silchenkova, A. N. Ilichev, M. Ya. Bykhovsky, V. Yu. Bychkov
Abstract
The paper compares the properties and activity of palladium clusters deposited on aluminum oxides of different phase compositions obtained by different methods. The numbers of palladium atoms available for the adsorption of hydrazine were determined for each catalyst. A correlation was found between the number of such atoms and the rate of hydrogen formation in the decomposition reaction of hydrazine monohydrate. It was concluded that an active palladium catalyst for the decomposition of hydrazine can be obtained using a modified support with a large specific surface area. The specific surface area and its modification determined the surface coverage with the active reagent. Obviously, the study of the role of various properties of supports in the formation of the active phase should be continued.
{"title":"Influence of Support Properties on the State and Activity of Supported Palladium in the Decomposition Reaction of Hydrazine Monohydrate","authors":"V. A. Matyshak, O. N. Silchenkova, A. N. Ilichev, M. Ya. Bykhovsky, V. Yu. Bychkov","doi":"10.1134/s0023158424601748","DOIUrl":"https://doi.org/10.1134/s0023158424601748","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The paper compares the properties and activity of palladium clusters deposited on aluminum oxides of different phase compositions obtained by different methods. The numbers of palladium atoms available for the adsorption of hydrazine were determined for each catalyst. A correlation was found between the number of such atoms and the rate of hydrogen formation in the decomposition reaction of hydrazine monohydrate. It was concluded that an active palladium catalyst for the decomposition of hydrazine can be obtained using a modified support with a large specific surface area. The specific surface area and its modification determined the surface coverage with the active reagent. Obviously, the study of the role of various properties of supports in the formation of the active phase should be continued.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200013","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 : 2024-09-04DOI: 10.1134/s0023158424601633
D. Sh. Fakhretdinov, I. Sh. Yakupov, A. I. Iskhakova, E. R. Latypova, R. F. Talipov
Abstract
The formal kinetics of the interaction of acrylonitrile (AN) and cyclopentadiene (CPD) by the Diels–Alder reaction in the presence of industrial zeolites has been studied. The dependence of the reaction rate constants of interacting components on the geometric properties of porous materials was revealed. The established dependence had a negative extremum at a zeolite pore diameter of 4 Å. It was shown that, in the presence of zeolites, the rate constant of the reaction under consideration was lower than that in the reaction carried out without porous materials.
{"title":"Kinetics of the Interaction of Acrylonitrile with Cyclopentadiene in the Diels–Alder Reaction in the Presence of Synthetic Zeolites","authors":"D. Sh. Fakhretdinov, I. Sh. Yakupov, A. I. Iskhakova, E. R. Latypova, R. F. Talipov","doi":"10.1134/s0023158424601633","DOIUrl":"https://doi.org/10.1134/s0023158424601633","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The formal kinetics of the interaction of acrylonitrile (AN) and cyclopentadiene (CPD) by the Diels–Alder reaction in the presence of industrial zeolites has been studied. The dependence of the reaction rate constants of interacting components on the geometric properties of porous materials was revealed. The established dependence had a negative extremum at a zeolite pore diameter of 4 Å. It was shown that, in the presence of zeolites, the rate constant of the reaction under consideration was lower than that in the reaction carried out without porous materials.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200010","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/s0023158424601268
V. V. Azatyan
Abstract
The reasons for the mistakes underlying the neglect and denial of the reaction chains discovered by N.N. Semenov and S. Hinshelwood in the combustion of gases at pressures close to atmospheric are analyzed. A method for unequivocal experimental proof of the chain nature of gas combustion is described. Examples are given proving the chain nature of combustion and explosion in a wide range of pressures and temperatures.
摘要 分析了忽视和否认 N.N. Semenov 和 S. Hinshelwood 在接近大气压的气体燃烧中发现的反应链的错误原因。介绍了通过实验明确证明气体燃烧链式性质的方法。举例说明了在各种压力和温度下燃烧和爆炸的链式性质。
{"title":"Chapter II. Chain Nature of Ignition and Explosion of Gases at Atmospheric and High Pressures","authors":"V. V. Azatyan","doi":"10.1134/s0023158424601268","DOIUrl":"https://doi.org/10.1134/s0023158424601268","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The reasons for the mistakes underlying the neglect and denial of the reaction chains discovered by N.N. Semenov and S. Hinshelwood in the combustion of gases at pressures close to atmospheric are analyzed. A method for unequivocal experimental proof of the chain nature of gas combustion is described. Examples are given proving the chain nature of combustion and explosion in a wide range of pressures and temperatures.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200017","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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