Kinetics and Catalysis最新文献

{"title":"XPS Study of the Synthesis of Single-Site Catalysts Based on Ir(I) and Rh(I) Complexes Immobilized on the SiO2 Surface Using a P-Containing Linker","authors":"M. Yu. Smirnov,&nbsp;L. M. Kovtunova,&nbsp;A. V. Kalinkin,&nbsp;I. V. Skovpin,&nbsp;I. V. Koptyug,&nbsp;V. I. Bukhtiyarov","doi":"10.1134/S0023158423060150","DOIUrl":"10.1134/S0023158423060150","url":null,"abstract":"<p>Samples of model single-site catalysts based on iridium and rhodium were synthesized by immobilizing the complexes [Ir(COD)(IMes)Cl] and [Rh(COD)(IMes)Cl] (where COD is 1,5-cyclooctadiene and IMes is 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene) on silica, the surface of which was modified with a linker containing a diphenylphosphine group (Ph₂P). The supports were silicon plates with a flat surface coated with a layer of natural oxide 1–3 nm thick (Si–SiO₂(nat)) or with a specially grown SiO₂ film (∼300 nm) (Si–SiO₂(ox)). The states of chemical elements in the modified silicon plates and samples of model catalysts were determined by XPS. Based on the results obtained, the nature of the coordination of the immobilized complexes was assumed. Samples of the catalysts were tested in the reaction of gas-phase hydrogenation of propene with parahydrogen.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":"64 6","pages":"895 - 908"},"PeriodicalIF":1.3,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138621539","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}

{"title":"Mechanism of the Decomposition of Hydrazine Monohydrate on Pd/Al2O3 Studied by in Situ IR Spectroscopy","authors":"V. A. Matyshak,&nbsp;O. N. Silchenkova,&nbsp;A. N. Ilichev,&nbsp;M. Ya. Bykhovsky,&nbsp;R. A. Mnatsakanyan","doi":"10.1134/S0023158423060101","DOIUrl":"10.1134/S0023158423060101","url":null,"abstract":"<p>Pd-containing catalysts (1% Pd/Al₂O₃ and 5% Pd/Al₂O₃) supported on aluminum oxide were studied in the decomposition reaction of hydrazine monohydrate. According to in situ IR-spectroscopic data, hydrazine monohydrate was adsorbed in a linear form on the coordinatively unsaturated sites of the catalyst surface. As the temperature was increased, the adsorbed hydrazine monohydrate lost a water molecule with a change in the geometry of the molecular complex. The adsorption of hydrazine on a support and its diffusion onto palladium clusters is a more advantageous process than direct adsorption on active sites. This circumstance shows that the hydrazine adsorbed on the support can be an intermediate in the process of its decomposition. The test catalysts had a maximum activity at a temperature of about 100°C. At temperatures in a range of 100−120°C, the ratio between hydrogen and nitrogen concentrations in the reaction products was 2, which corresponds to 100% selectivity for hydrogen. The selectivity decreased significantly with the reaction temperature. The high selectivity for hydrogen at low temperatures was explained by the fact that N₂H₄ was chemisorbed through the formation of hydrogen–metal bonds. The hydrogen–metal bond strength in such a complex is higher than the nitrogen–metal bond strength; hence, the N−H bond breaking barrier is lower than the N−N bond breaking barrier, and this fact led to the breaking of an N–H bond and the preservation of an N–N bond. At elevated temperatures, some of the formed hydrogen atoms recombined, and the other reacted with the surface complexes of hydrazine to form the intermediate NH₃−NH₃, in which N–N bond breaking led to the appearance of ammonia molecules in the gas phase.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":"64 6","pages":"826 - 836"},"PeriodicalIF":1.3,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138617899","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}

{"title":"Tocopherol- and Ascorbic Acid–Inhibited Radical Chain Oxidation of Tetrahydrofuran","authors":"L. R. Yakupova,&nbsp;A. R. Migranov,&nbsp;R. A. Nasibullina,&nbsp;R. L. Safiullin","doi":"10.1134/S0023158423060198","DOIUrl":"10.1134/S0023158423060198","url":null,"abstract":"<p>The role of ascorbic acid and α-tocopherol in the radical chain oxidation of tetrahydrofuran at 309 K was studied. The reaction was initiated by <span>(2,2{kern 1pt} ')</span>-azobisisobutyronitrile. The rate of the process was monitored by oxygen consumption. The rate constant of the reaction of the tetrahydrofuran peroxyl radical with α-tocopherol was measured to be <i>k</i>₇ = (2.9 ± 0.6) × 10⁵ L mol^–1 s^–1. The effect of an aqueous solution of ascorbic acid on the rate of tetrahydrofuran oxidation was studied. The rate constant of the reaction of the tetrahydrofuran peroxyl radical with ascorbic acid was measured to be <i>k</i>₇ = (10.2 ± 1.0) × 10⁴ L mol^–1 s^–1. The effect of ascorbic acid on the α-tocopherol-inhibited oxidation of tetrahydrofuran was examined. It was shown that, when both inhibitors are used together, the induction period is equal to the sum of the induction periods of the individual compounds. The effective inhibition rate constant in this case is <i>k</i>₇ = (2.5 ± 0.5) × 10⁵ L mol^–1 s^–1.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":"64 6","pages":"759 - 764"},"PeriodicalIF":1.3,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138575311","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}

{"title":"Influence of Soot Particles on the Gas-Phase Methane Conversion into Synthesis Gas: The Role of H2O and CO2 Additives","authors":"A. R. Akhunyanov,&nbsp;P. A. Vlasov,&nbsp;V. N. Smirnov,&nbsp;A. V. Arutyunov,&nbsp;D. I. Mikhailov,&nbsp;V. S. Arutyunov","doi":"10.1134/S0023158423060010","DOIUrl":"10.1134/S0023158423060010","url":null,"abstract":"<p>The influence of the formation of microheterogeneous soot particles on the gas-phase conversion of rich mixtures of methane with oxygen into synthesis gas in a temperature range from 1500 to 1800 K under the conditions of an adiabatic reactor was studied by kinetic modeling. The effect of CO₂ and H₂O additives on this process was studied. The appearance of soot particles was observed in rich mixtures, starting from the fuel excess factor ϕ = 3.33. At relatively low temperatures of ~1500 K, a small amount of microheterogeneous soot particles was formed, which did not significantly affect other components of the reacting system. A noticeable effect of soot particles at this temperature was observed at a higher value of ϕ = 8.0. This was most clearly manifested in the temperature profile of the process, in which two maximums were observed at times of about 0.01 and 0.1 s upon the addition of water to the reacting mixture. In the case of CO₂ additions, the second maximum in the temperature profile was almost not pronounced. A complex temperature profile led to the appearance of the second concentration maximum of hydroxyl radicals OH at times of ~0.1 s. The addition of H₂O and CO₂ made it possible to vary the H₂/CO ratio in the synthesis gas over a wide range, which is necessary for the synthesis of various products. Because the added CO₂ under these conditions was actually involved in the chemical process of obtaining synthesis gas, its partial recirculation from the conversion products made it possible to reduce its emission in the production of synthesis gas.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":"64 6","pages":"700 - 715"},"PeriodicalIF":1.3,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138575300","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}

{"title":"Screening Stability and Kinetics of Superoxide Radical Anion in Dimethyl Sulfoxide Containing Ionic Liquids","authors":"Saba Humayun,&nbsp;Maan Hayyan,&nbsp;Yatimah Alias,&nbsp;Fazrizatul Shakilla Sani","doi":"10.1134/S0023158423930018","DOIUrl":"10.1134/S0023158423930018","url":null,"abstract":"<p>The hunt for sustainable solvents has been an expansive pursuit ever since the genesis of green chemistry and has yielded more ecological approaches involving new organic compounds that are simultaneously used as reaction media and catalysts, such as neoteric solvents. This work primarily investigated the suitability of various ionic liquids (ILs) as a reaction medium for chemical generation of superoxide radical anions (<span>({text{O}}_{2}^{{bullet - }})</span>). This was achieved by monitoring the stability of <span>({text{O}}_{2}^{{bullet - }})</span> over a period of 3 h via kinetic studies in the presence of ILs comprising ammonium, pyrrolidinium, imidazolium, guanidinium, morpholinium, and sulfonium-based cations combined with different anions, such as [TFSI]⁻, [TfO]⁻, [DCA]⁻, [DMP]⁻, [TCB]⁻, [FAP]⁻, [E₃FAP]⁻, [EtSO₄]⁻, [SCN]⁻, [Cl]⁻, and [I]⁻. Potassium superoxide (KO₂) salt, generated by dissolution of KO₂ in DMSO, was used as the source of <span>({text{O}}_{2}^{{bullet - }})</span>. Pursuant to our recent familiarity with literature, this work represents the first use of a guanidinium-based IL in the study of <span>({text{O}}_{2}^{{bullet - }})</span> stability. Following screening, it was found that consumption of generated <span>({text{O}}_{2}^{{bullet - }})</span> was highest in the presence of [C₄DMIm][I], at 35.25%. This highlights its instability in that medium. In contrast, <span>({text{O}}_{2}^{{bullet - }})</span> was generated as a well-stabilized species in DMSO containing [BMIm][Cl], [BMIm][TfO], [BMIm][TFSI], [PMIm][TFSI], [EMIm][TFSI], [TBAmm][TFSI], [EDMPAmm][TFSI], [N₂₁₁,mom][E₃FAP], [BMPyrr][TCB], [MOPyrr][TFSI], and [MOEMMo][TFSI]. Of the 22 ILs analyzed in this study, the lowest total consumption of <span>({text{O}}_{2}^{{bullet - }})</span> was observed in morpholinium-based IL at 0.04%, positioning it as the best medium for the chemical generation of <span>({text{O}}_{2}^{{bullet - }})</span>.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":"64 6","pages":"765 - 782"},"PeriodicalIF":1.3,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138575317","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}

{"title":"Kinetic Laws of Oxidation of para-tert-Butylcumene in the Presence of N-Hydroxyphthalimide","authors":"A. S. Frolov,&nbsp;E. A. Kurganova,&nbsp;V. N. Sapunov,&nbsp;R. A. Kozlovskii,&nbsp;G. N. Koshel’,&nbsp;E. M. Yarkina","doi":"10.1134/S002315842306006X","DOIUrl":"10.1134/S002315842306006X","url":null,"abstract":"<p>The kinetics of the oxidation of <i>para</i>-<i>tert</i>-butylcumene to hydroperoxide by molecular oxygen in the presence of <i>N</i>-hydroxyphthalimide was studied. By analyzing the laws of the formation of hydroperoxide and byproducts, a mathematical model of the process was constructed, which adequately describes the changes in the concentrations of the main components of the reaction over time. The main role of <i>N</i>-hydroxyphthalimide is to convert peroxide radicals into the corresponding hydroperoxides, thereby reducing the yield of byproducts by decreasing the quadratic chain termination rate. Moreover, the formed <i>N</i>-hydroxyphthalimide radicals increase the rate of hydrocarbon oxidation. Thus, the use of <i>N</i>-hydroxyphthalimide in hydrocarbon oxidation processes results in an increase in the rate and selectivity of hydroperoxide formation.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":"64 6","pages":"750 - 758"},"PeriodicalIF":1.3,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138623567","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}

{"title":"Palladium-Containing Catalysts Based on Functionalized Carbon Nanofibers for the Dehydrogenation of Methylcyclohexane","authors":"G. B. Veselov,&nbsp;D. M. Shivtsov,&nbsp;S. D. Afonnikova,&nbsp;I. V. Mishakov,&nbsp;A. A. Vedyagin","doi":"10.1134/S0023158423060174","DOIUrl":"10.1134/S0023158423060174","url":null,"abstract":"<p>The activity of palladium-containing catalysts based on functionalized carbon nanofibers prepared by an incipient wetness impregnation method in the dehydrogenation reaction of methylcyclohexane was investigated. Methylcyclohexane is considered as one of the most promising liquid hydrogen carriers. The dependence of the catalytic characteristics of the samples on the functionalization conditions of carbon nanofibers was studied. Using temperature-programmed desorption, it was shown that an increase in the treatment time of carbon nanofibers in concentrated nitric acid from 1 to 3 h increased the number of hydroxyl groups on their surface, and treatment for 6 h contributed to a rise in the concentration of carboxyl groups and their derivatives (esters and anhydrides). Additional calcination of the functionalized nanofibers in an inert atmosphere at 530°C yielded a sample containing predominantly hydroxyl groups. The presence of hydroxyl groups on the surface of the carbon material had a positive effect on the performance of the catalysts, while the presence of carboxyl groups led to a decrease in the yield of toluene. It was assumed that the observed differences in catalyst activity were due to differences in the dispersion and localization of palladium particles.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":"64 6","pages":"925 - 927"},"PeriodicalIF":1.3,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138627328","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}

{"title":"Prospects of Using Ruthenium within the Composition of Three-Way Palladium–Rhodium Catalysts","authors":"Yu. V. Shubin,&nbsp;P. E. Plyusnin,&nbsp;R. M. Kenzhin,&nbsp;A. A. Vedyagin","doi":"10.1134/S0023158423060149","DOIUrl":"10.1134/S0023158423060149","url":null,"abstract":"<p>The possibility of using ruthenium in the composition of palladium–rhodium catalysts used to neutralize the exhaust gases of vehicles with gasoline engines was investigated. The thermolysis of a supported precursor in oxidizing and reducing atmospheres led to the formation of samples with different initial catalytic activity. The stability of trimetallic systems was compared under conditions of prompt thermal aging with that of reference samples of similar chemical composition but obtained by mechanical mixing of monometallic catalysts. The results obtained allowed us to conclude that the alloy nanoparticles were more stable, and the thermolysis of the precursor in a reducing atmosphere contributed to a higher initial activity of the catalyst in the oxidation of CO. According to the X-ray photoelectron spectroscopy data, the high thermal stability of trimetallic catalysts was due to a constant ratio between metals on the support surface in the course of the catalytic reaction.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":"64 6","pages":"922 - 924"},"PeriodicalIF":1.3,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138575195","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}

{"title":"Implications of Active Intermediate and Olefin Attachment Position in the Piperine Metathesis","authors":"Aline A. C. França,&nbsp;Eliada A. da Silva,&nbsp;Benedito S. Lima-Neto,&nbsp;Valdemiro P. de Carvalho Júnior,&nbsp;José M. Elias de Matos,&nbsp;José L. da Silva Sá","doi":"10.1134/S0023158423060058","DOIUrl":"10.1134/S0023158423060058","url":null,"abstract":"<p>First and second generation of Grubbs catalysts (G1 and G2) were applied in the piperine olefin metathesis under different conditions. G1 was used in self-metathesis, G2 was implemented in both, self and cross-metathesis of piperine with eugenol. Results allowed to implicate about the main intermediate of the reaction and the position of olefin attachment to the catalyst, assuming that the reaction follows a pathway where 2A=B olefin leads to the formation of A=A and B=B. In addition, the results contributed to the studies of catalyst’s reactivity when the olefin metathesis product required the high electronic effect of the <i>N</i>-heterocyclic of G2. In this paper, the highest activity of G2 in the olefin metathesis of eugenol was observed when the first intermediate was Ru-eugenol-moiety in the cross-metathesis of the piperine with eugenol. This demonstrates that the acidity of the new carbene in the intermediate species causes inactivity only in the reaction with piperine.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":"64 6","pages":"783 - 792"},"PeriodicalIF":1.3,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138575127","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}

{"title":"Dimethyl Ether Carbonylation in the Presence of an H-MOR Zeolite Modified with Copper, Cobalt, and Magnesium","authors":"M. A. Kipnis,&nbsp;R. S. Galkin,&nbsp;E. A. Volnina,&nbsp;I. A. Belostotskii,&nbsp;G. N. Bondarenko,&nbsp;O. V. Arapova","doi":"10.1134/S0023158423060071","DOIUrl":"10.1134/S0023158423060071","url":null,"abstract":"<p>The adsorption, temperature-programmed desorption, and carbonylation of dimethyl ether (DME) in the presence of mordenite and ferrierite (SiO₂/Al₂O₃ ≈ 20, Zeolyst International) is studied. The effect of introducing Cu, Co, and Mg cations by ion exchange is discussed. Dimethyl ether carbonylation is conducted at 200°С, a pressure of 3 MPa, and a space velocity of 8000 mL g^–1 h^–1 in the following mixture (vol %): DME, ⁓2.2; CO, 92.8–95.5; and the rest, N₂. After an induction period, the methyl acetate content in the presence of mordenite is about 4–5 times higher than that in the presence of ferrierite. Water, methanol, and hydrocarbons are formed in trace amounts. The introduction of Cu, Co, and Mg cations into mordenite by ion exchange (single ion-exchange run, cation/Al ratio of no more than 35%) leads to an increase not only in stability, but also in activity in the DME carbonylation reaction. It is found that an increase in the content of copper (from 1.19 to 2.23 wt %) and magnesium (from 0.62 to 1.8 wt %) has different effects on activity. It increases in the case of copper and decreases in the case of magnesium. The prereduction of a copper-exchanged mordenite leads to the appearance of metallic copper particles on the surface of the mordenite crystallites and a decrease in activity. According to in situ diffuse reflectance infrared spectroscopy, the introduction of magnesium cations by three ion-exchange runs leads to a significant decrease in the number of Brønsted acid sites (BASes) in both the 12-MR and 8-MR channels of the mordenite. The catalytic characteristics of ferrierite hardly change upon the introduction of copper and magnesium by ion exchange.</p>","PeriodicalId":682,"journal":{"name":"Kinetics and Catalysis","volume":"64 6","pages":"849 - 861"},"PeriodicalIF":1.3,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138575196","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}