检索结果-南通市图书馆

Substrate specificity in the biomimetic catalytic aerobic oxidation of styrene and cyclohexanone by metalloporphyrins: kinetics and mechanistic study

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Green Chemical Engineering 2021年第2期2卷 217-223页

作者： Xian-tai zhou Hong-Bing Ji Fine Chemical Industry Research Institute Sun Yat-sen UniversityGuangzhou510275China School of Chemical Engineering Guangdong University of Petrochemical TechnologyMaoming525000China

Substrate specificity is a hallmark of enzymatic *** this work,the biomimetic catalytic oxidation of styrene and cyclohexanone by iron(III)porphyrins and molecular oxygen was carried out,and remarkable differences in efficiency were *** specificity of the substrates for biomimetic catalytic oxidation was investigated by kinetics and mechanistic *** studies revealed that the oxidation of styrene followed Michaelis-Menten kinetics with KM=8.99 mol L^(-1),but the oxidation of cyclohexanone followed first-order kinetics with kobs=1.46×10^(-4) s^(-1),indicating that the styrene epoxidation by metalloporphyrins exhibited characteristics of enzyme-like catalysis,while the oxidation of cyclohexanone was in agreement with the general rules of chemical *** catalytic mechanisms for the two substrates were discussed by operando electron paramagnetic resonance spectroscopy,operando UV-vis spectroscopy,and KI/starch *** specificity was concluded to be attributed to the stability of high-valence species and oxygen transfer rate.

关键词： Substrate specificity Kinetics Oxidation Metalloporphyrins Mechanism

Effects of Si Addition and Long-Term Thermal Exposure on the Tensile Properties of a Ni–Mo–Cr Superalloy

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2015年第8期28卷 951-957页

作者： zhou-Feng Xu Jia-Sheng Dong Li Jiang Zhi-Jun Li Xing-tai zhou Thorium Molten Salts Reactor Center Shanghai Institute of Applied Physics Chinese Academy of Sciences University of Chinese Academy of Sciences Institute of Metal Research Chinese Academy of Sciences

The effect of long-term thermal exposure on the grain boundary carbides and the tensile behavior of two kinds of Ni–Mo–Cr superalloys with different silicon contents（0 and 0.46 wt%） was investigated. Experimental results showed granular M2C carbides formed at the grain boundaries after exposure for 100 h for the non-silicon alloy. Furthermore, these fine granular M2C carbides will transform into plate-like M6C carbides as exposure time increases. For the Si-containing alloys,only the granular M6C carbides formed at the grain boundaries during the whole exposure time. The coarsening of the grain boundary carbides occurred in both alloys with increasing exposure time. In addition, the coarsening kinetics of the grain boundary carbides for the non-silicon alloy is faster than that of the standard alloy. The tensile properties of both alloys are improved after exposure for 100 h due to the formation of nano-sized grain boundary carbides. The grain boundary carbides are coarsened more seriously for non-silicon alloys than that of Si-containing alloys, resulting in a more significant decrease in the tensile strength and elongation for the former case. Silicon additions can effectively inhibit the severe coarsening of the grain boundary carbides and thus avoid the obvious deterioration of the tensile properties after a long-term thermal exposure.

关键词： Ni–Cr–Mo Silicon Carbides Mechanical properties

Upgraded control system designed for SECRAL

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2017年第9期28卷 57-62页

作者： Jian-Jun Su Yan-Yu Wang De-tai zhou Wen-Xiong zhou Jian-Chuan Zhang Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000 China Chongqing University Chongqing 400044 China

To improve the accuracy and usability of the superconducting electron cyclotron resonance ion source with advanced design in Lanzhou(SECRAL), an upgraded version of the control system was designed and tested. This paper details the architecture of the optimized control system and presents the results of its use in the long-term operation of the accelerator. The control system software, based on Visual C++, was developed following the model-view-controller architecture design pattern. The data acquisition system was based on a field-programmable gate array integrated circuit. In addition, control strategies were optimized for higher operational stability. The upgraded control system was tested with a U^(33+) ion beam at SECRAL, where it provided a data acquisition time of less than 1 ms. The fast reaction time and highprecision data processing during beam tuning verified the stability and maintainability of the control system.

关键词：控制系统设计电子回旋共振离子源模型-视图-控制器现场可编程门阵列数据采集系统稳定性控制优化控制系统控制系统软件

Liquid-phase epoxidation of propylene with molecular oxygen by chloride manganese meso-tetraphenylporphyrins

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2022年第8期35卷 61-65页

作者： Xian-tai zhou Ling-Ling Wang Yang Li Hong-Bing Ji Fine Chemical Industry Research Institute School of Chemical Engineering and TechnologySun Yat-sen UniversityZhuhai 519082China Fine Chemical Industry Research Institute School of ChemistrySun Yat-sen UniversityGuangzhou 510275China School of Chemical Engineering Guangdong University of Petrochemical TechnologyMaoming 525000China

Propylene molecule owns two active sites,the direct epoxidation of propylene by dioxygen is still a challenge due to the limitation of *** this work,the direct liquid-phase propylene aerobic epoxidation protocol by chloride manganese meso-tetraphenylporphyrin(MnTPPCl)was *** conversion of propylene was 12.7%,and the selectivity towards PO(propylene oxide)reached up to 80.5%.The formation of PO was attributed to the mechanism via high-valent Mn species,which was confirmed by means of in situ UV–vis spectrum.

关键词： Propylene Epoxidation Dioxygen Manganese porphyrins Liquid phase

Different efficiency toward the biomimetic aerobic oxidation of benzyl alcohol in microchannel and bubble column reactors: Hydrodynamic characteristics and gas–liquid mass transfer

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2023年第3期55卷 84-92页

作者： Qi Han Xin-Yuan Zhang Hai-Bo Wu Xian-tai zhou Hong-Bing Ji Fine Chemical Industry Research Institute School of Chemical Engineering and TechnologySun Yat-sen UniversityZhuhai 519082China Fine Chemical Industry Research Institute School of ChemistrySun Yat-sen UniversityGuangzhou 510275China Huizhou Research Institute Sun Yat-sen UniversityHuizhou 516081China

The selective aerobic oxidation of benzyl alcohol to benzaldehyde has attracted considerable attention because benzaldehyde is a high value-added product. The rate of this typical gas–liquid reaction is significantly affected by mass transfer. In this study, CoTPP-mediated(CoTPP: cobalt(II) mesotetraphenylporphyrin) selective benzyl alcohol oxidation with oxygen was conducted in a membrane microchannel(MMC) reactor and a bubble column(BC) reactor, respectively. We observed that 83% benzyl alcohol was converted within 6.5 min in the MMC reactor, but only less than 10% benzyl alcohol was converted in the BC reactor. Hydrodynamic characteristics and gas–liquid mass transfer performances were compared for the MMC and BC reactors. The MMC reactor was assumed to be a plug flow reactor,and the dimensionless variance was 0.29. Compared to the BC reactor, the gas–liquid mass transfer was intensified significantly in MMC reactor. It could be ascribed to the high gas holdup(2.9 times higher than that of BC reactor), liquid film mass transfer coefficient(8.2 times higher than that of BC reactor), and mass transfer coefficient per unit interfacial area(3.8 times higher than that of BC reactor). Moreover,the Hatta number for the MMC reactor reached up to 0.61, which was about 15 times higher than that of the BC reactor. The computational fluid dynamics calculations for mass fractions in both liquid and gas phases were consistent with the experimental data.

关键词： Membrane microchannel reactor Gas-liquid flow Mass transfer Benzyl alcohol Computational fluid dynamics(CFD) Bubble column reactor

Cyclohexene Promoted Efficient Biomimetic Oxidation of Alcohols to Carbonyl Compounds Catalyzed by Manganese Porphyrin under Mild Conditions

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2020年第5期38卷 458-464页

作者： Xiao-Hui Liu Hai-Yang Yu Can Xue Xian-tai zhou Hong-Bing Ji School of Chemical Engineering and Technology Sun Yat-sen UniversityZhuhaiGuangdong 519082China Fine Chemical Industry Research Institute Key Laboratory of Low-Carbon Chemistry&Energy Conservation of Guangdong ProvinceSchool of ChemistrySun Yat-sen UniversityGuangzhouGuangdong 510275China School of Chemical Engineering Guangdong University of Petrochemical TechnologyMaomingGuangdong 525000China

Selective oxidation of alcohols to corresponding carbonyl compounds is one of the most important processes both in academic and application *** a kind of biomimetic catalyst,metalloporphyrins-catalyzed aerobic oxidation of alcohols with aldehyde as hydrogen donator is gathering much ***,using olefins as another kind hydrogen donator for aerobic oxidation of alcohols has not been *** this study,a system comprising managenese porphyrin and cyclohexene for biomimetic aerobic oxidation of alcohols to carbonyl compounds was *** catalytic system exhibited excellent catalytic performance and selectivity towards the corresponding products for most primary and secondary alcohols under mild *** on the results obtained from experiments as well as in situ EPR(electron paramagnetic resonance)and UV-vis spectroscopy,the role of cvclohexene was demonstrated.

关键词： alcohols carbonyl system

Propylene epoxidation coupled with furfural oxidation over Pt(Ⅱ) TPP porphyrin with molecular oxygen

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Green Chemical Engineering 2024年第4期5卷 519-525页

作者： Hong-Qi Li Hai-Yang Yu Yang Li Xiao-Qi He Xian-tai zhou Huizhou Research Institute Sun Yat-sen UniversityHuizhou516081China School of Chemical Engineering and Technology Sun Yat-sen UniversityZhuhai519082China

The development of green route for preparing propylene oxide(PO)with molecular oxygen is of significance both in academic and *** this work,propylene epoxidation coupled with furfural oxidation catalyzed by platinum meso-tetraphenylporphyrin(Pt(Ⅱ)TPP)has been *** conversion and PO selectivity reached up to 56%and 83%,***,furfural was almost completely converted to furoic *** on operando characterizations and electron paramagnetic resonance(EPR)tests,a mechanism involved high-valent Pt species was *** work is expected to provide a potential application prospects for producing PO and furoic acid simultaneously in chemical industry.

关键词： Propylene Epoxidation Molecular oxygen Furfural Platinum porphyrins

Corrosion behavior of pure metals(Ni and Ti)and alloys(316H SS and GH3535)in liquid GaInSn

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2024年第3期35卷 70-83页

作者： Jian-Hui Yu Hong-Xia Xu Xiang-Xi Ye Bin Leng Han-Xun Qiu Xing-tai zhou School of Materials and Chemistry University of Shanghai for Science and TechnologyShanghai 200093China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China

In this study,the interactions between a Ga-based liquid metal,GaInSn,and several metal materials,including pure metals(Ni and Ti)and alloys(316H stainless steel(SS)and GH3535),at 650℃were *** aim was to evaluate the corrosion performance and select a suitable candidate material for use as a molten salt manometer diaphragm in thermal energy storage *** results indicated that the alloys(316H SS and GH3535)exhibited less corrosion than pure metals(Ni and Ti)in liquid ***-rich binary intermetallic compounds were found to form on the surfaces of all the tested metal materials exposed to liquid GaInSn,as a result of the decomposition of liquid GaInSn and its reaction with the constituent elements of the metal *** corrosion mechanism for all the tested materials exposed to liquid GaInSn was also investigated and proposed,which may aid in selecting the optimal candidate material when liquid GaInSn is used as the pressure-sensing medium.

关键词： Metal materials Liquid GaInSn Corrosion Intermetallic compounds Thermal energy storage systems

Manganese porphyrin-mediated aerobic epoxidation of propylene with isoprene: A new strategy for simultaneously preparing propylene epoxide and isoprene monoxide

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2023年第3期34卷 236-239页

作者： Xian-tai zhou Hai-Yang Yu Yang Li Hai-Bo Wu Hong-Bing Ji Fine Chemical Industry Research Institute School of Chemical Engineering and TechnologySun Yat-sen UniversityZhuhai 519082China Fine Chemical Industry Research Institute School of ChemistrySun Yat-sen UniversityGuangzhou 510275China Huizhou Research Institute Sun Yat-sen UniversityHuizhou 516081China Advanced Energy Science and Technology Guangdong Laboratory Huizhou 516003China

The direct epoxidation of propylene by O_(2) is a significant and challenging topic. The key factor for this homogeneous aerobic epoxidation is the activation of molecular oxygen under mild conditions. In this work,the aerobic epoxidation of propylene catalyzed by manganese porphyrins was achieved in the presence of isoprene. Isoprene contains an allyl methyl group, and the α-H can be easily removed to achieve the activation of molecular oxygen. The conversion of propylene was 38% and the selectivity toward propylene oxide(PO) was up to 87%. The role of isoprene was demonstrated, and a plausible mechanism was proposed. The protocol reported herein is expected to provide a strategy for the simultaneous preparation of propylene oxide and isoprene monoxide.

关键词： Propylene Epoxidation Dioxygen Isoprene Metalloporphyrins