{"title":"Effects of metallic cobalt crystal phase on catalytic activity of cobalt catalysts supported on carbon nanotubes in Fischer–Tropsch synthesis","authors":"A. N. Pour, M. Housaindokht","doi":"10.1177/1468678319862438","DOIUrl":"https://doi.org/10.1177/1468678319862438","url":null,"abstract":"The effects of metallic cobalt crystal phase on catalytic activity of cobalt catalysts in the Fischer–Tropsch synthesis were investigated in a continuous spinning basket reactor. The cobalt catalysts were prepared by impregnation of the cobalt active phase in a microemulsion system on multiwall carbon nanotube supports. A series of cobalt catalysts with different Co particle sizes was prepared by variation of the water-to-surfactant molar ratio from 2 to 12 in the microemulsion system. The X-ray diffraction results validate a complex composition of cobalt phases containing cobalt oxides and metallic cobalt with hexagonal close-packed and face-centered cubic phases. The results show that larger cobalt particles exhibit more face-centered cubic and less hexagonal close-packed metallic cobalt. The experimental results show that the catalysts with higher fractions of hexagonal close-packed phase exhibited higher conversion in the Fischer–Tropsch reaction.","PeriodicalId":20859,"journal":{"name":"Progress in Reaction Kinetics and Mechanism","volume":"4 1","pages":"316 - 323"},"PeriodicalIF":0.7,"publicationDate":"2019-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79752751","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":"Reactivity and kinetic studies of benzofuran hydrodeoxygenation over a Ni2P-O/MCM-41 catalyst","authors":"Xueya Dai, Huaihui Song, Hualin Song, Jing Gong, Feng Li, Yanxiu Liu","doi":"10.1177/1468678319825909","DOIUrl":"https://doi.org/10.1177/1468678319825909","url":null,"abstract":"A nickel phosphide hydrodeoxygenation catalyst (Ni2P-O/MCM-41) was prepared using a new synthetic method. The as-prepared catalyst was evaluated in the hydrodeoxygenation of benzofuran, and the effects of reaction temperature, pressure, and the H2/liquid ratio were investigated. A pseudo first-order model was employed to describe the reaction kinetics of benzofuran hydrodeoxygenation over the Ni2P-O/MCM-41 catalyst. The reaction rate constants (k1–k5) at different temperatures were determined according to this model. At 533 K, the conversion of 2-ethylphenol in to ethylbenzene began to increase dramatically, and the yield of O-free product, ethylcyclohexane, started to increase rapidly. At 573 K, 3.0 MPa, and a H2/liquid ratio of 500 (V/V), the conversion of benzofuran over Ni2P-O/MCM-41 reached 93%, and the combined yield of O-free products was 91%. Contact time analysis indicated that demethylation was not favored over the Ni2P-O/MCM-41 catalyst.","PeriodicalId":20859,"journal":{"name":"Progress in Reaction Kinetics and Mechanism","volume":"29 1","pages":"307 - 315"},"PeriodicalIF":0.7,"publicationDate":"2019-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78135749","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}
Huang Weijia, Ming-Hua Chen, Zhen-Tao An, Li Zhang, Zhibao Jiang
{"title":"Simulation of thermal reaction mechanism between energetic components of hydroxyl-terminated polybutadiene propellant based on quantum chemical calculation","authors":"Huang Weijia, Ming-Hua Chen, Zhen-Tao An, Li Zhang, Zhibao Jiang","doi":"10.1177/1468678319860989","DOIUrl":"https://doi.org/10.1177/1468678319860989","url":null,"abstract":"In this article, hybrid functional B3LYP method is used to construct the reactant structure of energetic components in propellant at the bhandhlyp/6-31g(d) level, and to calculate the closed-shell layer of the system. At the bhandhlyp/6-31g(d) level, the energy difference (activation energy) between the transition state and the reactant was calculated and the reaction mechanism between energetic components was analyzed. It is found that the O30 atom of RDX first breaks off from the nitro group and is easier to break away from RDX and interact with the vertex atom Al1 of the Al13 cluster. With the further separation of O30, it also acts with Al11 until it completely breaks away from N26 atom. The activation energy of this reaction is 56.448 × 103 J mol−1. The oxygen dioxide atom in ammonium perchlorate is more likely to interact with the Al11 atom of the Al13 cluster. With the reaction proceeding, the O22 atom will not completely separate from the Cl19 atom. The activation energy of the reaction is 27.830 × 103 J mol−1.","PeriodicalId":20859,"journal":{"name":"Progress in Reaction Kinetics and Mechanism","volume":"62 1","pages":"324 - 335"},"PeriodicalIF":0.7,"publicationDate":"2019-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78149441","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}
Dragana Marković-Nikolić, M. Cakic, G. Petković, G. Nikolić
{"title":"Kinetics, thermodynamics and mechanisms of phosphate sorption onto bottle gourd biomass modified by (3-chloro-2-hydroxypropyl) trimethylammonium chloride","authors":"Dragana Marković-Nikolić, M. Cakic, G. Petković, G. Nikolić","doi":"10.1177/1468678319858149","DOIUrl":"https://doi.org/10.1177/1468678319858149","url":null,"abstract":"The sorption kinetics and thermodynamic parameters of phosphate removal from aqueous solution using quaternary ammonium–modified bottle gourd biomass as a sorbent were studied in a batch reactor. The cationic sorbent, containing trimethylammonium and hydroxypropyl groups, was obtained through the chemical reactions of the lignocellulosic Lagenaria vulgaris shell with (3-chloro-2-hydroxypropyl)trimethylammonium chloride. Experimental data of phosphate sorption from aqueous solutions of different initial concentrations (5–140 mg P L−1) have been analysed by reaction kinetics and diffusion models. The characteristic rate constants calculated by linear and non-linear regression analyses of the experimental results are presented. The phosphate sorption reaches equilibrium in 20–30 min, depending on the initial phosphate concentration. The maximum sorption capacity of quaternary ammonium–modified bottle gourd (QABG) sorbent was 18 mg P g−1 at 20 oC. The sorption system is best described by a non-linear equation of the pseudo first-order model (R2 > 0.996). The Weber–Morris model indicated that the sorption process took place in three steps, whereby the intra-particle diffusion is not the only rate-controlling step. In addition, the effect of temperature (20 oC–50 oC) on sorption kinetics was also investigated. The various thermodynamic parameters suggest that phosphate sorption is favoured and is an exothermic process. The activation energy and the sticking probability confirmed that anion exchange is the dominant mechanism. These results provide valuable information for the potential use of agricultural residues in the treatment of wastewaters.","PeriodicalId":20859,"journal":{"name":"Progress in Reaction Kinetics and Mechanism","volume":"28 1","pages":"267 - 285"},"PeriodicalIF":0.7,"publicationDate":"2019-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77823208","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":"Bi24Br10+xAg x O31 nanostructure, a new reusable photocatalyst for efficient removal of Acid Blue 92 from model wastewaters under visible light","authors":"M. Padervand, E. Jalilian","doi":"10.1177/1468678319860023","DOIUrl":"https://doi.org/10.1177/1468678319860023","url":null,"abstract":"Bi24Br10+xAg x O31 nanosheets were prepared by a facile single-step co-precipitation method in the presence of 1-butyl-3-methylimidazolium bromide ionic liquid as the bromide source and template agent. The products were well characterized by X-ray powder diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, diffuse reflectance spectroscopy, nitrogen adsorption–desorption isotherms using Brunauer–Emmett–Teller analysis, Fourier transform infrared spectroscopy and transmission electron microscopy. The X-ray powder diffraction pattern confirmed the presence of both Bi24O31Br10 and AgBr crystalline phases in the structure. In addition, the scanning electron microscopy micrographs and transmission electron microscopy image indicated that the sample had sheet-like morphology and the thickness of the sheets was below 100 nm. According to the photocatalytic experiments, the product was exceptionally efficient for the degradation of Acid Blue 92 solutions under visible light. Also, the results of recycling experiments indicated the high capacity of the prepared nanosheets to effect repeated treatment of the wastewater solution, which is of great importance in being introduced as a catalyst in practical applications.","PeriodicalId":20859,"journal":{"name":"Progress in Reaction Kinetics and Mechanism","volume":"2 1","pages":"257 - 266"},"PeriodicalIF":0.7,"publicationDate":"2019-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72872639","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":"Kinetics and mechanism of formation of the complex [Ru(CN)5INH]3− through the ligand substitution reaction between the aquapentacyanoruthenate(II) anion and isoniazid","authors":"Rupali Yadav, R. Naik","doi":"10.1177/1468678319825737","DOIUrl":"https://doi.org/10.1177/1468678319825737","url":null,"abstract":"The formation kinetics of the complex, [Ru(CN)5INH]3−, formed through the ligand substitution reaction between isoniazid (INH) and aquapentacyanoruthenate(II) ([Ru(CN)5H2O]3−), have been investigated, under pseudo first-order conditions, as a function of concentrations of [INH] and [Ru(CN)5H2O]3−, ionic strength and temperature at pH = 4.0 ± 0.02 in 0.2 M NaClO4 spectrophotometrically at 502 nm (λmax of intense yellow colour product [Ru(CN)5INH]3−) corresponding to metal-to-ligand charge-transfer transitions, in aqueous medium. The pseudo first-order condition was maintained by taking at least 10% excess of [INH] over [Ru(CN)5H2O]3−. The stoichiometry of the reaction product was found to be 1:1 which was further supported and characterized using elemental analysis, infrared, nuclear magnetic resonance and mass spectrometric techniques. Thermodynamic and kinetic parameters have also been computed, using the Eyring equation, and the values of ΔH≠, Ea, ΔG≠ and ΔS≠ were found to be 47.3 kJ mol−1, 49.8 kJ mol−1, −8.62 kJ mol−1 and 187.6 J K−1mol−1, respectively. The reaction was found to obey first-order kinetics with respect to [INH]. It exhibited a negative salt effect on the rate upon variation of ionic strength of the medium. A tentative mechanistic scheme was proposed on the basis of experimental findings.","PeriodicalId":20859,"journal":{"name":"Progress in Reaction Kinetics and Mechanism","volume":"69 1","pages":"244 - 256"},"PeriodicalIF":0.7,"publicationDate":"2019-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90444474","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":"Does the single-walled carbon nanotube affect the rate constant of binding of biotin to streptavidin? Molecular dynamics simulation perspective","authors":"O. Soltani, M. Bozorgmehr, M. Momen-Heravi","doi":"10.1177/1468678319825710","DOIUrl":"https://doi.org/10.1177/1468678319825710","url":null,"abstract":"The interaction of biotin and streptavidin in the presence and absence of a carbon nanotube was studied by molecular dynamics simulation. With respect to the Arrhenius dependence of the rate constants with temperature, those of streptavidin–biotin complex formation ( k 1 ) and streptavidin–biotin complex dissociation ( k − 1 ) were calculated from molecular dynamics simulation trajectories. Nanotube has reduced the amount of and k1 and k1. However, the biotin position in streptavidin does not change much. The results obtained from MMPBSA calculations show that the contribution of the van der Waals forces to both systems (in the absence and presence of the nanotube) was greater than that of electrostatic forces. The presence of the nanotube also led to the reduction of van der Waals and electrostatic forces in the interaction of biotin with streptavidin. However, this reduction was greater for electrostatic forces. In the absence of a nanotube, there are four hydrogen bonds between streptavidin and biotin, which are related to the residues Ser27, Tyr43, Ser45 and Ser88. In the presence of the nanotube, the hydrogen bonding of biotin with Ser45 is removed.","PeriodicalId":20859,"journal":{"name":"Progress in Reaction Kinetics and Mechanism","volume":"96 1","pages":"234 - 243"},"PeriodicalIF":0.7,"publicationDate":"2019-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81285331","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":"Study on syngas methanation mechanism over Ni4/MCM-41 catalyst based on density functional theory","authors":"Jiaying Zhang","doi":"10.1177/1468678319854871","DOIUrl":"https://doi.org/10.1177/1468678319854871","url":null,"abstract":"The density functional theory method is employed to systematically explore the mechanism of syngas methanation on the Ni4/MCM-41 catalyst surface. The calculation results show that the optimal pathway of CH4 formation is CO + H → CHO + H → CH2O + H → CH3O → CH3 + H → CH4 with the rate-determining step of CH3O direct dissociation. Because the activation energy for the direct dissociation of CH3O species is much lower than that for the CH3OH formation (198.6 vs 264.8 kJ mol−1), there is almost no by-product CH3OH that appeared in the products of the syngas methanation over the Ni4/MCM-41 catalyst. Compared with other conventional nickel-based methanation catalysts, Ni4/MCM-41 catalyst is an excellent methanation catalyst with high selectivity of CH4.","PeriodicalId":20859,"journal":{"name":"Progress in Reaction Kinetics and Mechanism","volume":"54 1","pages":"222 - 233"},"PeriodicalIF":0.7,"publicationDate":"2019-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87148565","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}
Hasnia Abdeldjebar, Y. Belmiloud, Wassila Djitli, Sofiene Achour, M. Brahimi, B. Tangour
{"title":"Proton transfer in the benzimidazolone and benzimidazolthione tautomerism process catalyzed by polar protic solvents","authors":"Hasnia Abdeldjebar, Y. Belmiloud, Wassila Djitli, Sofiene Achour, M. Brahimi, B. Tangour","doi":"10.1177/1468678319825740","DOIUrl":"https://doi.org/10.1177/1468678319825740","url":null,"abstract":"The tautomeric equilibrium of benzimidazolone and benzimidazolthione have been studied by the density functional theory method using the CAM-B3LYP functional together with the 6-311G(d,p) basis set. Two separate mechanisms have been investigated: a direct intramolecular transfer using the polarizable continuum model and an indirect proton transfer assisted by a molecule of solvent (C6H12, H2O, CH3OH, and H2O2). In both cases, the results obtained indicate that ketone and thione are the most stable forms. However, the enhanced height of the activation barrier for the four-center mechanisms describing the tautomerism reaction as a direct intramolecular transfer implicates a relatively disadvantaged process. The participation of a polar protic solvent molecule allows the lowering of the activation energy barrier. Potential energy profiles of keto-enol and thio-enol tautomerism assisted by methanol and water are very different. The former one describes a concerted mechanism but the latter does not because it is associated with asynchronous processes that take place during the thio-enol tautomerism.","PeriodicalId":20859,"journal":{"name":"Progress in Reaction Kinetics and Mechanism","volume":"24 1","pages":"143 - 156"},"PeriodicalIF":0.7,"publicationDate":"2019-05-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89312481","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}
Joanna Drzeżdżon, Agnieszka Piotrowska-Kirschling, L. Chmurzyński, D. Jacewicz
{"title":"Aquation reaction of iminodiacetate complex of oxidovanadium(IV) with 2,2’-bipyridine induced by Fe(III) ions: Kinetic studies","authors":"Joanna Drzeżdżon, Agnieszka Piotrowska-Kirschling, L. Chmurzyński, D. Jacewicz","doi":"10.1177/1468678319850496","DOIUrl":"https://doi.org/10.1177/1468678319850496","url":null,"abstract":"The kinetics of the aquation reaction of the [VO(ida)(bipy)]·2H2O (VO(ida)(bipy)) complex (where ida = iminodiacetate anion and bipy = 2,2’-bipyridine) promoted by [Fe(H2O)6]3+ ions were investigated in aqueous solutions. Spectrophotometric studies were carried out at different temperatures in the range of 293.15–313.15 K. The concentration of the [Fe(H2O)6]3+ (Fe3+) ions was kept within the range of 2 × 10–4 to 8 × 10–4 mol L–1, and the concentration of VO(ida)(bipy) was 1 × 10–3 mol L–1. The values of the observable reaction rate constants were calculated based on the Glint computer program. Furthermore, the mechanism for the aquation of VO(ida)(bipy), induced by Fe(III) ions, has been proposed.","PeriodicalId":20859,"journal":{"name":"Progress in Reaction Kinetics and Mechanism","volume":"65 1","pages":"300 - 306"},"PeriodicalIF":0.7,"publicationDate":"2019-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84459262","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}