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Kinetics of oxidation reaction for Magnetite Pellets

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Journal of Iron and Steel Research(International) 2013年第9期20卷 16-20页

作者： LIANG Ru-quan YANG Shuo YAN Fu-sheng HE Ji-cheng Key Laboratory of National Education Ministry for Electromagnetic Process of Materials Northeastern University Research Institute Northeastern University

An experiment for the oxidation process of single magnetite pellet and theoretical analysis based on modi lied unreacted core shrinking （MUCS） model were carried out, and the controlling mechanisms of the initial and de veloping reactions were examined, respectively. From the study of the initial reaction, it was found that the chemical reaction of surface is the controlling step of the overall reaction when the temperature is up to about 750 K, while the mass transfer through the gaseous boundary layer dominates the reaction rate when the temperature is above 750 K. As the reaction developing within the pellet, the mass transfer through the produced layer becomes the controlling step. In addition, the effects of reaction conditions （such as oxygen concentration, temperature） on the fractional oxidation of magnetite pellet were determined.

关键词： magnetite pellet shaft furnace kinetics oxidation reaction controlling step

Characteristics of oxidation reaction of Rare-Earth Chlorides in Eutectic Chloride Melt

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Journal of Rare Earths 2007年第S1期25卷 13-16页

作者： Yung-Zun Cho Hee-Chul Yang Hee-Chul Eun Eung-Ho Kim In-Tae Kim Advanced Fuel Cycle Process Development Korea Atomic Energy Research InstituteDaejeon 305-353Korea

oxidation reaction of rare earth chlorides(Ce/Pr/Nd/EuCl3) in a LiCl-KCl eutectic molten salt was carried out using an oxygen sparging method. Regardless of the sparging time and the molten salt temperature, oxychlorides (NdOCl, PrOCl) and oxides(CeO, Eu2O3, PrO2) were formed as a oxidation products(i.e. precipitates) by the reaction with oxygen. The conversion efficiency of the rare earth elements to the precipitates increases with the sparging time and the molten salt temperature. In the conditions of 650 ℃ of a molten salt temperature and 420 min of a sparging time, the values of the conversion efficiency of the used rare earth chlorides were over 99.9%. Information on the hydrodynamics of an oxygen-molten salt two phase flow system is essential since its hydrodynamics strongly affect the oxidation reaction of rare earth elements in an eutectic chloride melts.

关键词： oxidation reaction oxygen sparging flow regime conversion efficiency rare earths

Metal-organic framework-based materials as key components in electrocatalytic oxidation and reduction reactions

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Journal of Energy Chemistry 2023年第12期87卷 540-567,I0014页

作者： Soheila Sanati Ali Morsali Hermenegildo García Department of Chemistry Faculty of Basic SciencesTarbiat Modares UniversityTehran 14115175Iran Instituto Universitario de Tecnología Química Universidad Politecnica de ValenciaConsejo Superior de Investigaciones CientíficaSUniversitat Politècnica de ValènciaValència 46022Spain

Studies have extensively addressed the development of electrocatalytic technologies for energy storage and conversion,fuel production,and environmental *** processes such as different oxidation and reduction reactions play a vital and significant role in these *** this regard,efficient,inexpensive,and stable electrocatalysts capable can significantly promote electrochemical *** features of metal–organic frameworks(MOFs)such as their high porosity,tunable structure,size,and pore shape,high surface area,and redox properties have introduced them as an ideal electrocatalyst *** review is thus aimed at elucidating the role of MOF-based materials(pristine,derivatives and composites)as efficient electrocatalysts in energy and sensing-related oxidation and reduction reactions such as oxygen reduction reaction(ORR),hydrogen oxidation reaction(HOR),carbon dioxide reduction reaction(CO_(2)RR),urea oxidation reaction(UOR),alcohol oxidation reaction(AOR),nitrogen reduction reaction(NRR),and glucose oxidation reaction(GOR)in advanced energy and sensing ***,the structure–property relationship of the electrocatalyst was elaborated for each electrocatalytic ***,perspectives on the potential research topics for practical use of MOF-based electrocatalysts are *** present review can improve the interest in MOF-based electrocatalysts to study different oxidation and reduction reactions in energy and sensing systems.

关键词： Metal-organic frameworks Electrocatalyst oxidation reaction Reduction reaction

Zero sintering-induced shrinkage of porous oxide ceramics

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Journal of Materials Science & Technology 2023年第28期159卷 184-193页

作者： Kai Miao Liangjie Liu Jiwei Cao Ran He Sai Li Lingling Wu Zhongliang Lu Dichen Li State Key Laboratory for Manufacturing Systems Engineering Xi’an Jiaotong UniversityXi’an 710049China KOCEL Intelligent Machinery Co. Ltd.Yinchuan 750021China School of Engineering University of LeicesterLeicester LE17RHUnited Kingdom

Porous oxide ceramics are widely used in extreme working conditions owing to their excellent resistance to high temperatures and ***,sintering is an inevitable process applied to ceramics,from the green body to the final *** highly complex structures exacerbate the shrinkage-induced ir-regular deformation and crack formation in the sintering process.A pioneering approach is developed in this study to achieve zero shrinkage for porous alumina ceramics during multistep sintering,using a combination of active fillers-ZrAl 3 and Al 75 Si *** response surface method is used to optimize the material compositions and sintering process,to achieve shrinkages of less than 0.05%for the entire *** sintering expansion mechanism is investigated by analyzing the pyrolysis and microstructures of samples at different *** combination of ZrAl 3 and Al 75 Si 25 can attain the continuous expansion of the matrix in a wide temperature range of 600-1400°***,typical alumina com-ponents are fabricated and used to verify the effectiveness of the proposed *** to shrinkage suppression,the profile deviation of the samples is less than 0.1 mm,and the proportion of microcracks is reduced by 97.8%.The suggested approach shows potential applications in near-net,low-defect fabrica-tion of complex fine ceramic components.

关键词： Porous oxide ceramics Sintering-induced shrinkage oxidation reaction reaction sintering

Hydrogen bond-mediated polyoxometalate-based metal-organic networks for efficient and selective oxidation of aryl alkenes to aldehydes

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Tungsten 2022年第2期4卷 109-120页

作者： Wen-Jing Cui Si-Meng Zhang Ze-Yu Tian Chen Li Yi-Meng Wang Bo-Rong Yu Yuan-Yuan Ma Zhan-Gang Han Hebei Key Laboratory of Organic Functional Molecules National Demonstration Center for Experimental Chemistry EducationCollege of Chemistry and Materials ScienceHebei Normal UniversityShijiazhuang050024China

Selective oxidation of aryl alkenes to aldehydes is an important approach to produce industrial raw materials,in which the exploration of an efficient heterogeneous catalyst is significant but *** this work,three hydrogen bond-mediated polyoxometalate(POM)-contained metal–organic networks with the formulas of[Ni(BTD)2(H2O)2]2[SiW12O40]·12H2O(1),[Ni(BTD)2(H2O)]2[SiW12O40]·6H2O(2)and[Zn(BTD)2(H2O)]2[SiW12O40]·6H2O(3)(BTD=4H,4ʹH-[3,3ʹ-bi(1,2,4-triazole)]-5,5ʹ-diamine)were hydrothermally synthesized,in which the metal–organic fragments interact with POM clusters via abundant hydrogen bonding to extend the structure into three-dimensional supramolecular *** be explored as heterogenous catalysts,compounds 1–3 showed high catalytic activity and selectivity for the selective oxidation of styrene to *** them,compound 1 exhibits the highest performance with ca.99%styrene conversion and ca.99%selectivity of benzaldehyde in 5 ***,compound 1 displays rich substrate compatibility,recyclability and good structural stability.A series of experiments demonstrated that the high performance of compound 1 should be attributed to the synergistic effect among polyoxoanion and coordination-unsaturated metal centers in metal–organic fragments,which facilitates the activation of H2O2 and styrene substrates,thus enhancing the catalytic performance.

关键词： Polyoxometalate Metal-organic network Heterogeneous catalyst oxidation reaction

An Efficient Extraction-Free Method for Oxidative Desulfurization of Model Fuels Employing Cross-Linked Polyionic Liquid Phosphotungstate Catalysts

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China Petroleum Processing & Petrochemical Technology 2022年第3期24卷 10-20页

作者： Yuan Dandan Zhang Ling Yin Guoqing Wang Yuanyuan Zhang Jiaojing Provincial Key Laboratory of Oil&Gas Chemical Technology College of Chemistry&Chemical EngineeringNortheast Petroleum UniversityDaqing 163318China

An efficient extraction-free oxidative desulfurization(ODS)process using a series of cross-linked polyionic liquid phosphotungstate(CLPIL-PW)catalysts is *** cross-linked PILs were prepared with DVB and 1-n-alkyl-3-vinyl imidazole hydrobromide(alkyl=ethyl,butyl,octyl,dodecyl),and were then assembled with phosphotungstic acid(H_(3)PW_(12)O_(40))to form the *** CLPIL-PWs have been applied to the oxidative removal of dibenzothiophene(DBT)from model oil with H_(2)O_(2) as an *** effects of ionic liquid(IL)cationic species,varying the DVB/IL molar ratio in the polymerization process,and varying operating conditions were *** CLPIL-PWs were characterized by inductively coupled plasma(ICP)mass spectrometry,elemental analysis,scanning electron microscopy(SEM),Fourier transform infra-red(FTIR)spectroscopy,X-ray diffraction(XRD),^(13)C and^(31)P nuclear magnetic resonance(NMR)*** polydivinylbenzene-co-1-n-octyl-3-vinyl imidazole phosphotungstate(P(DVB-OVIm)PW)exhibited the highest DBT removal efficiency(99.9%)and remarkable recyclability,and could be reused eight times without reducing its ***,an extraction-free ODS mechanism is proposed.

关键词： desulfurization polyionic liquids(PILs) cross-linking phosphotungstic acid oxidation reaction

Kinetics of oxidation of dimethyl trisulfide by potassium permanganate in drinking water

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Frontiers of Environmental Science & Engineering 2012年第2期6卷 171-176页

作者： Xiaoyan MA Shifei HU Hongyu WANG Jun LI Jing HUANG Yun ZHANG Weigang LU Qingsong LI Municipal Department of Architecture Engineering College Zhejiang University of TechnologyHangzhou 310014China National Water Quality Monitoring Net of City Water Supply Hangzhou Station Hangzhou 310014China Water Resources and Environmental Institute Xiamen University of TechnologyXiamen 361005China

Metabolites of algae such as geosmin, 2-methylisoborneol etc. are reported to induce pungent odors into drinking water and attract additional scientific attention. Recently, in China, taste and odor outbreaks in drinking water supply have become increasingly common. In source water affected by eutrophication, dimethyl trisulfide, speculated to be produced by decayed algae, was found to be the source of taste and odor issues and can be removed effectively by usual oxidation agents. In this experimental study, batch scale tests were carried out focusing on the removal of dimethyl trisulfide. reaction kinetics of dimethyl trisulfide oxidized by potassium permanganate in water had been studied; influence factors such as pH, organic substrate, other existed taste, and odor contaminant in equivalent concentration were also discussed. Results showed that dimethyl trisulfide can be removed by potassium permanganate efficiently; the ratio can reach more than 70% with oxidant dosage of 4 mg·L and contact time prolonged to 120 min. The dimethyl trisulfide decomposition followed a second-order kinetics pattern with a rate constant = 0.00213 L·(min·mg) . Typically, the degradation rate of dimethyl trisulfide was increased with the increasing KMnO dosage, but dramatically dropped with the increasing levels of humic acid (1.8–4.5 mg·L ) and other odor-causing compounds (e.g. -cyclocitral, 0–1886.0 μg·L ). Solution pH (5.2–9.0) and initial dimethyl trisulfide concentration did not significantly affected the degradation. This study demonstrates that KMnO oxidation is an effective option to remove dimethyl trisulfide from water.

关键词： odor and taste oxidation reaction reactionkinetics water treatment

Stepwise oxidation of Ketene Dithioacetal

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Chinese Chemical Letters 2001年第10期12卷 865-868页

作者： Chen, K Yang, HZ Nankai Univ Inst Elementoorgan Chem State Key Lab Elementoorgan Chem Tianjin 300071 Peoples R China

Stepwise oxidation of ketene dithioacetal is found and the different oxidation products changed with the amount of oxidant, temperature and reaction time.

关键词： oxidation reaction ketene dithioacetal hydrogen peroxide

Palladium-Catalyzed oxidation of Dihydromyrcene to Citronellal in Supercritical Carbon Dioxide

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Chinese Journal of Chemistry 2004年第11期22卷 1384-1386页

作者：冉学光江焕峰朱新海 Department of Applied Chemistry South China University of Technology Guangzhou Guangdong 510640 China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic Chemistry Chinese Academy of Sciences Shanghai 200032 China Laboratory of Cellulose and Lignocellulosics Chemistry Guangzhou Institute of Chemistry Chinese Academy of Sciences Guangzhou Guangdong 510650 China

Citronellal was the major product of catalytic oxidation of dihydromyrcene with oxygen using the catalyst comprised of (MeCN)2PdClNO2 and CuCl2 in a tertiary alcohol in supercritical carbon dioxide. It was found that the chemoselectivity of the reaction and the yield of citronellal were greatly affected by the pressure of carbon dioxide, the reaction temperature and the molar ratio of Pd/Cu.

关键词： supercritical carbon dioxide dihydromyrcene Pd-catalyzed oxidation reaction citronellal