Progress in Reaction Kinetics and Mechanism最新文献_第4页

Theoretical studies on the kinetics of the hydrogen-abstraction reactions from 1,3,5-trioxane and 1,4-dioxane by OH radicals 羟基自由基对1,3,5-三氧环和1,4-二氧环吸氢反应动力学的理论研究

IF 0.7 4区化学

Progress in Reaction Kinetics and Mechanism Pub Date : 2020-02-01 DOI: 10.1177/1468678319899252

V. Saheb, Aidin Bahadori

{"title":"Theoretical studies on the kinetics of the hydrogen-abstraction reactions from 1,3,5-trioxane and 1,4-dioxane by OH radicals","authors":"V. Saheb, Aidin Bahadori","doi":"10.1177/1468678319899252","DOIUrl":"https://doi.org/10.1177/1468678319899252","url":null,"abstract":"Theoretical investigations have been performed on the kinetics of bimolecular hydrogen-abstraction reactions of 1,3,5-trioxane and 1,4-dioxane cyclic ethers with OH radicals. Hydrogen abstraction from both axial and equatorial positions of 1,3,5-trioxane and 1,4-dioxane was considered. Optimization of the structures, and the calculation of energies, vibrational frequencies and moments of inertia for all the stationary points including reactants, hydrogen-bonded complexes, transition states and products were carried out using density functional theory at the M06-2X level together with the MG3S basis set. Single-point energy calculations on the optimized points were obtained at the CBS-QB3 level. The calculations show that the title reactions proceed through relatively strong hydrogen-bonded complexes due to the hydrogen bonding between the OH radicals and the oxygen atoms of the cyclic ethers. A two-transition state model (an inner tight transition state and an outer loose transition state) was employed to compute the hydrogen-abstraction rate coefficients. The rate coefficients were also computed using conventional transition state theory considering a tight transition state for the purpose of comparison. It was found that when the reactions proceed via inner transition states with relative energies higher than the reactants, the computed rate coefficients are underestimated by conventional transition state theory.","PeriodicalId":20859,"journal":{"name":"Progress in Reaction Kinetics and Mechanism","volume":"75 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2020-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86412876","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}

引用次数: 1

Magnetically separable Fe3O4-supported Ru–Ni bimetallic catalysts for diformyltricyclodecanes hydrogenation to value-added fine chemicals 磁性可分离fe3o4负载Ru-Ni双金属催化剂用于二甲酰三环癸烷加氢制备高附加值精细化学品

IF 0.7 4区化学

Progress in Reaction Kinetics and Mechanism Pub Date : 2020-01-01 DOI: 10.1177/1468678319825732

Hongyi Li, Yubo Ma

引用次数: 1

Influence of sulfating method on La–Ni–S2O82–/ZrO2–Al2O3 solid superacid catalyst for n-pentane isomerization 硫酸盐酸化对La-Ni-S2O82 - / ZrO2-Al2O3固体超强酸催化剂正戊烷异构化的影响

IF 0.7 4区化学

Progress in Reaction Kinetics and Mechanism Pub Date : 2020-01-01 DOI: 10.1177/1468678319897724

Haiqiang Zhao, Hua Song, Lele Zhao, Feng Li

{"title":"Influence of sulfating method on La–Ni–S2O82–/ZrO2–Al2O3 solid superacid catalyst for n-pentane isomerization","authors":"Haiqiang Zhao, Hua Song, Lele Zhao, Feng Li","doi":"10.1177/1468678319897724","DOIUrl":"https://doi.org/10.1177/1468678319897724","url":null,"abstract":"La–Ni–S2O82–/ZrO2–Al2O3 catalysts were successfully prepared by two different methods of sulfate impregnation, and the physico-chemical properties of the catalysts were characterized by X-ray diffraction, Brunauer–Emmett–Teller analysis, Fourier transform infrared spectroscopy, pyridine adsorption–infrared spectroscopy, and X-ray photoelectron spectroscopy techniques. Catalytic activities were evaluated in a fixed-bed flow reactor using n-pentane isomerization as the probe reaction. Compared with catalyst La–Ni–S2O82–/ZrO2–Al2O3-I, prepared by the traditional impregnation method, the catalyst La–Ni–S2O82–/ZrO2–Al2O3-W, prepared by the incipient-wetness impregnation method, possessed higher pore volume, pore size, sulfur content, and stronger Brønsted acid sites. The catalytic activity for La–Ni–S2O82–/ZrO2–Al2O3-W was maintained at around 56% within 3000 min with an isopentane selectivity of 88% which showed much greater stability than that of La–Ni–S2O82–/ZrO2–Al2O3-I. This can be attributed to the fact that (1) the large pore size and pore volume of La–Ni–S2O82–/ZrO2–Al2O3-W can largely suppress carbon deposition and (2) the more numerous and stronger Brønsted acid sites for La–Ni–S2O82–/ZrO2–Al2O3-W guaranteed to provide enough acid sites for isomerization during the reaction process.","PeriodicalId":20859,"journal":{"name":"Progress in Reaction Kinetics and Mechanism","volume":"1 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83128292","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}

引用次数: 0

Prediction of esterification rate constants for secondary alkan-2-ols based on one- and two-parameter Taft equations 基于单参数和双参数Taft方程的仲烷烃-2-醇酯化速率常数预测

IF 0.7 4区化学

Progress in Reaction Kinetics and Mechanism Pub Date : 2020-01-01 DOI: 10.1177/1468678319825731

J. Vojtko, Jaroslav Durdiak, Zuzana Lukáčová-Chomisteková, P. Tomčík

引用次数: 3

A [1 + 2] cycloaddition instead of usual [2 + 3] cycloaddition between the B12N12 cluster and methyl azide: Potential energy surface calculations and Born–Oppenheimer molecular dynamics simulations B12N12簇与叠氮化物之间的[1 + 2]环加成取代了通常的[2 + 3]环加成:势能表面计算和Born-Oppenheimer分子动力学模拟

IF 0.7 4区化学

Progress in Reaction Kinetics and Mechanism Pub Date : 2020-01-01 DOI: 10.1177/1468678319900581

P. Pakravan, Seyyed Amir Siadati

引用次数: 0

A mechanistic study of 1,3,5-trisubstituted-1,2,3-triazoles by Ab initio method 用从头算法研究1,3,5-三取代-1,2,3-三唑的机理

IF 0.7 4区化学

Progress in Reaction Kinetics and Mechanism Pub Date : 2020-01-01 DOI: 10.1177/1468678320923295

Jinsong Gu, Xiuhui Lu

引用次数: 0

A highly efficient and stable Ni/SBA-15 catalyst for hydrogen production by ethanol steam reforming 一种高效稳定的乙醇蒸汽重整制氢Ni/SBA-15催化剂

IF 0.7 4区化学

Progress in Reaction Kinetics and Mechanism Pub Date : 2020-01-01 DOI: 10.1177/1468678319891842

Xia An, J. Ren, Wei-Ping Hu, Xu Wu, Xianmei Xie

{"title":"A highly efficient and stable Ni/SBA-15 catalyst for hydrogen production by ethanol steam reforming","authors":"Xia An, J. Ren, Wei-Ping Hu, Xu Wu, Xianmei Xie","doi":"10.1177/1468678319891842","DOIUrl":"https://doi.org/10.1177/1468678319891842","url":null,"abstract":"The production of hydrogen by steam reforming of ethanol was carried out on SBA-15-supported nano NiO catalyst synthesized by the equivalent-volume impregnation method with two different Ni sources (nickel nitrate and nickel sulfamate). The catalyst was characterized by N2 adsorption–desorption, X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy to examine the physical and chemical properties. The activity tests were performed with the steam, with water/ethanol molar ratio ranging from 2:1 to 15:1, the N2 flow rate from 20 to 120 mL min−1 to determine the space-time, and the temperature range from 623 to 923 K on the two different Ni source catalysts. A favorable operating condition was established at 823 K using water/ethanol = 6 molar ratio and carrier gas (N2) flow of more than 50 mL min−1 for nickel nitrate source, but for nickel sulfamate source, the optimum temperature changed to 773 K and other conditions were the same as for the nickel nitrate source. After eliminating the influence of internal and external diffusion factors, an empirical power-law kinetic rate equation was derived from the experimental data. The non-linear regression method was used to estimate the kinetic parameter. The activation energy of the catalyst was then calculated, and the supported nickel nitrate and nickel sulfamate catalysts were 25.345 and 41.449 kJ mol−1, respectively, which was in agreement with the experimental and model-predicted results.","PeriodicalId":20859,"journal":{"name":"Progress in Reaction Kinetics and Mechanism","volume":"23 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75202560","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}

引用次数: 2

Oxidation reaction mechanism and kinetics between OH radicals and alkyl-substituted aliphatic thiols: H-abstraction pathways 羟基自由基与烷基取代脂肪族硫醇之间的氧化反应机理和动力学:吸氢途径

IF 0.7 4区化学

Progress in Reaction Kinetics and Mechanism Pub Date : 2019-11-27 DOI: 10.1177/1468678319886129

A. Tahan, A. Shiroudi

引用次数: 2

1-Norbornyl cation may be in equilibrium with 2-norbornyl cation 1-降冰片基阳离子可能与2-降冰片基阳离子处于平衡状态

IF 0.7 4区化学

Progress in Reaction Kinetics and Mechanism Pub Date : 2019-08-22 DOI: 10.1177/1468678319861319

A. Mamantov

引用次数: 0

New kinetic analysis of the Fenton reaction: Critical examination of the free radical – chain reaction concept 芬顿反应的新动力学分析:对自由基-链式反应概念的批判性考察

IF 0.7 4区化学

Progress in Reaction Kinetics and Mechanism Pub Date : 2019-07-31 DOI: 10.1177/1468678319860991

M. L. Kremer

{"title":"New kinetic analysis of the Fenton reaction: Critical examination of the free radical – chain reaction concept","authors":"M. L. Kremer","doi":"10.1177/1468678319860991","DOIUrl":"https://doi.org/10.1177/1468678319860991","url":null,"abstract":"Using [H2O2] in the molar range, the reaction with Fe2+ has two phases: in the first rapid phase, only a small fraction of the total O2 is evolved; the bulk of the gas is formed in a slow second phase. In interpretations based on the free radical model of Barb et al., the first phase has been identified with the ‘Fenton reaction’ (reaction of Fe2+with H2O2), while the second with catalytic decomposition of H2O2 by Fe3+ ions. This interpretation is not correct. A new analysis of the model shows that (1) it is a chain reaction having no termination steps and (2) the ‘Fenton part’ alone consists of two phases. It starts with rapid evolution of O2 via a five-membered chain reaction (first phase). When [Fe2+] becomes low, evolution of O2 continues in a three-membered chain reaction at a greatly reduced rate (second phase). In later stages of the second phase, Fe3+ catalysis contributes to O2 evolution. Thus, the amount of O2 formed in the rapid phase cannot be identified with the total amount formed in the ‘Fenton reaction’ but only with that formed in its first phase. Computer simulations of O2 evolution based on the model of Barb et al. and rate constants show a definite dependence of this quantity on the initial [H2O2] – in contrast to the experimentally found independence. More satisfactory, but not complete, agreement with measured data could be reached in simulations using a non-radical model. Some of the difficulty has been due to the determination of the exact position of the end of the first phase. The transition between the two phases of the reaction occurs in a short, but finite time interval. It has been shown that the quantity ‘total amount of O2 evolved in the Fenton reaction’ (subtracting the part due to Fe3+catalysis) is not accessible to experimental determination nor to theoretical calculation.","PeriodicalId":20859,"journal":{"name":"Progress in Reaction Kinetics and Mechanism","volume":"63 1","pages":"289 - 299"},"PeriodicalIF":0.7,"publicationDate":"2019-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86935824","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}

引用次数: 5