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Effects of internals on macroscopic fluid dynamics in a bubble column

Chinese Journal of Chemical engineering 2025年第1期77卷 19-29页

作者： Shijie Liu Jin Liang Qin Li Hui Yu Haoliang Wang Xiangyang Li Chao Yang School of Chemical Engineering Sichuan UniversityChengdu 610065China CAS Key Laboratory of Green Process and Engineering State Key Laboratory of Petroleum Molecular&Process EngineeringInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China

The effects of internals on liquid mixing and gas-liquid mass transfer have rarely been investigated in bubble columns,and the commonly used measurement method overestimates significantly overall gas ***,gas holdup measurement method is improved by conducting multi-point liquid level measurement and using net fluid volume instead of bed volume to calculate gas ***,a stable conductivity method for liquid macromixing has been established by shielding large bubbles using#16nylon ***,the influences of internal coverage(=12.6%,18.9% and 25.1%) on macroscopic fluid dynamics in a bubble column with a free wall area are systematically *** is found that the presence of internals has a notable effect on macroscopic fluid *** overall gas holdup and gas-liquid volumetric mass transfer coefficient decrease,and the macromixing time decreases with the increase of internal cross-sectional area *** are mainly caused by the uneven distribution of airflow due to the low resistance in the free wall *** design makes maintenance easier,but in reality,the reactor performance has *** improvements will be made to the reactor performance based on such a configuration through flow guidance using baffles.

关键词： Bubble column Internals Macroscopic fluid dynamics Mixing Mass transfer

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Microwave synthesis of vanadium phosphorus oxide catalysts for n-butane selective oxidation

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Particuology 2025年第1期96卷 97-105页

作者： Zhiqi Xie Shengwen Zhu Xingsheng Wang Shuang Wei Ruirui Zhang Ruixia Liu Beijing Key Laboratory of Ionic Liquids Clean Process CAS Key Laboratory of Green Process and EngineeringInstitute of Process EngineeringInnovation Academy for Green ManufactureCASBeijing100190China University of Chinese Academy of Sciences Beijing100049China

Vanadium phosphorus oxide (VPO) catalysts play a crucial role in the selective oxidation of n-butane to maleic anhydride (MA), and their catalytic performance is highly dependent on the synthesis conditions of the precursor. This study focuses on a facile and rapid microwave irradiation method for the synthesis of VPO precursors. The effects of microwave exposure time and power on morphology, crystalline structure, and catalytic effect of VPO are investigated. The relationship between the structure and performance of the catalysts is explored by SEM, TEM, BET, FT-IR, XRD, Raman, and XPS characterization. The results demonstrate that microwave power is the key factor influencing the size, thickness, surface area, and active surfaces of vanadium pyrophosphate after activation. Additionally, the P/V ratio and Lat-O/Sur-O ratio on the catalyst surface vary with different synthesis conditions, which significantly affect the catalytic performance. In conclusion, the microwave-synthesized VPO catalyst exhibits remarkable enhancements in n-butane conversion (87.2%) and maleic anhydride (MA) selectivity (70.2%), which shows high efficiency and energy-saving, providing a new research direction for the future preparation of VPO catalysts.

关键词： Microwave synthesis VPO catalyst n-butane oxidation Maleic anhydride yield

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Construction of multifunctional lanthanum manganese mixed nanoparticles mediated by ionic liquids for selective aerobic oxidation of cyclohexane

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Rare Metals 2024年第5期43卷 2205-2221页

作者： Hao Li Rui-Rui Zhang Ke-Xin Li Shuang Wei Yu-Mei Liu Rui-Xia Liu Beijing Key Laboratory of Ionic Liquids Clean Process CAS Key Laboratory of Green Process and EngineeringState Key Laboratory of Multiphase Complex SystemsInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Selective oxidation of alkanes to produce highvalue chemicals is an essential strategy and means to realize efficient utilization of *** this work,a strategy of lanthanum manganese mixed metal oxides(LMMO)regulated via a facile ionic liquid(IL)-assisted hydrothermal method was proposed to construct the multifunctional catalysts,which exhibited excellent catalytic performance in the selective aerobic oxidation of *** 8.9%cyclohexane conversion with 90%KA oi(cyclohexanol and cyclohexanone)selectivity was achieved over the optimal LMMO catalyst under mild *** effects of anion type,carbon chain length and concentration of ILs on the structure and properties of catalysts were investigated through various characterizations,indicating the structure-directing and template effect of ILs on the multifunctional *** formation of self-assembled spherical nanoparticles followed the"dissolution-nucleation-proliferation"mechanism with the introduction of 1-butyl-3-methylimidazolium hydrogen sulfate,ascribing the synergistic effect between the microenvironment of ILs and the hydrothermal ***,the high reactive oxygen concentration redox capacity,and suitable basic sites of LMMO catalysts mediated by ILs enhance the activation of C-H bonds and molecular oxygen,simultaneously influencing the adsorption and desorption of the substrate.A comprehensive understanding of the high KA oil selectivity and radical reaction mechanism was elucidated based on in situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and radical trapping *** recycling and regeneration experiments further illuminated that the removal of adsorbed cyclohexanone acting on the LMMO catalyst was the key to achieve high KA oil selectivity.

关键词： Ionic liquids Nanoparticle Multifunctional catalyst Cyclohexane oxidation

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Role of methoxy and C_(α)-based substituents in electrochemical oxidation mechanisms and bond cleavage selectivity of β-O-4 lignin model compounds

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green Energy & Environment 2024年第1期9卷 114-125页

作者： Yang Zhou Qiang Zeng Hongyan He Kejia Wu Fuqiao Liu Xuehui Li School of Chemistry and Chemical Engineering The Guangdong Provincial Key Laboratory of Green Chemical Product TechnologyState Key Laboratory of Pulp and Paper EngineeringSouth China University of TechnologyGuangzhouGuangdong510640China CAS Key Laboratory of Green Process and Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing100190China

In order to better understand the specific substituent effects on the electrochemical oxidation process of β-O-4 bond, a series of methoxyphenyl type β-O-4 dimer model compounds with different localized methoxyl groups, including 2-(2-methoxyphenoxy)-1-phenylethanone, 2-(2-methoxyphenoxy)-1-phenylethanol, 2-(2-methoxyphenoxy)-1-(4-methoxyphenyl)ethanone, 2-(2-methoxyphenoxy)-1-(4-methoxyphenyl)ethanol, 2-(2,6-dimethoxyphenoxy)-1-(4-methoxyphenyl)ethanone, 2-(2,6-dimethoxyphenoxy)-1-(4-methoxyphenyl)ethanol have been selected and their electrochemical properties have been studied experimentally by cyclic voltammetry, and FT-IR spectroelectrochemistry. Combining with electrolysis products distribution analysis and density functional theory calculations, oxidation mechanisms of all six model dimers have been explored. In particular, a total effect from substituents of both para-methoxy(on the aryl ring closing to Cα) and Cα-OH on the oxidation mechanisms has been clearly observed, showing a significant selectivity on the Cα-Cβbond cleavage induced by electrochemical oxidations.

关键词： Lignin model compounds β-O-4 dimers Electrochemical oxidation Oxidation mechanisms Substituent effect

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Construction of Ni single-atom coordinated with doped N and S elements for mild hydrogenation of methyl acrylate to methyl propionate

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Nano Research 2025年第1期18卷 217-224页

作者： Taolue Sun Chen Jian Gang Wang Hui Zhao Guoliang Zhang Zengxi Li Chunshan Li State Key Laboratory of Mesoscience and Engineering CAS Key Laboratory of Green Process and EngineeringBeijing Key Laboratory of Ionic Liquids Clean ProcessInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China Huizhou Institute of Green Energy and Advanced Materials Huizhou 516081China Advanced Energy Science and Technology Guangdong Laboratory Huizhou 516081China

Although the nickel-based catalyst is able toexhibit comparative catalytic activity to noble metal formethyl acrylate hydrogenation,it requires strict reactioncondition,which can be improved by regulation ofcoordination *** this study,we constructed akind of Ni single-atom coordinated with N and S(Ni-NSC)through the pyrolysis of organic Ni-based precursors at600℃.The existence and fine structure of Ni single-atom were confirmed by the spherical electron microscopicobservation in combination with the X-ray absorption spectroscopy(XAS)*** addition,the catalytichydrogenation assessment suggested that the as-prepared Ni-NSC catalyst exhibited higher activity and stability than theNi/NSC supported catalyst prepared by incipient wetness impregnation *** remarkable catalytic activity was dueto the high dispersion and density of Ni single-atom and weak adsorption energy of intermediates on these Ni sites.

关键词： methyl acrylate mild hydrogenation Ni single-atom coordination environment adsorption energy

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Density functional theory studies of Pt-based catalysts for CO oxidation

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Science China(Technological Sciences) 2025年第3期68卷 54-71页

作者： Xue LI Yang ZOU Yongqi ZHAO Xiaolong LIU Tingyu ZHU CAS Key Laboratory of Green Process and Engineering Institute of Process EngineeringChinese Academy of SciencesBeijing100190China Key Laboratory of Green and High-value Utilization of Salt Lake Resources Chinese Academy of SciencesXining810008China

CO is highly toxic and seriously harmful to human health,so it is meaningful to control CO emissions,especially from industrial *** oxidation is regarded to be an effective method for CO removal,in which Pt-based catalysts show excellent *** of catalytic CO oxidation employing Pt-based catalysts often encounter challenges such as CO poisoning,challenges in activating O_(2),significant temperature sensitivity,and inadequate tolerance to water and sulfur *** experimental hurdles have been corroborated by density functional theory(DFT)computations,which model adsorption,reaction pathways,and electronic structures at catalyst *** analysis has elucidated the underlying mechanisms behind these limitations,laying the foundation for enhancing the efficacy of Pt-based catalysts within the scope of academic *** has been used intensively in recent years to study the reaction mechanism and functioning characteristics of Pt-based catalysts in CO ***,advancements in research on DFT experiments on Pt-based catalysts are *** review provides a comprehensive overview and insights into the mechanism of CO adsorption on the surface of single-atom and multi-atom Pt-based catalysts,its effect on CO oxidation performance,and reaction pathways of CO oxidation in the hope of providing theoretical guidance for the structural design of most effective catalysts.

关键词： platinum catalytic oxidation carbon monoxide density functional theory

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Selective cyclohexane oxidation enhancement by electronic structures regulation of metal-poly(ionic liquid)s

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green Chemical engineering 2024年第2期5卷 213-221页

作者： Ying Jin Shengxin Chen Ruirui Wang Yumei Liu Xinxin Li Yingwei Li Ruirui Zhang Ruixia Liu Henan Institute of Advanced Technology Zhengzhou UniversityZhengzhou450001China Beijing Key Laboratory of Ionic Liquids Clean Process CAS Key Laboratory of Green Process and EngineeringState Key Laboratory of Multiphase Complex SystemsInstitute of Process EngineeringInnovation Academy for Green ManufactureCASBeijing100190China

Poly(ionic liquids)(PILs)combined with the macromolecular structure and unique properties of ionic liquids show unlimited potential in *** this work,a series of metal-based PIL with different ionic ratios were prepared for the selective oxidation of *** analysis reveals that different degrees of ionization could adjust the Co-N sites of the catalysts efficiently,leading to significant changes in their electronic structure,which strongly relate to catalytic performance in oxidation.20.07%cyclohexane conversion and 13.06%cyclohexanone and cyclohexanol(KA oil)yield can be achieved by metal-based PILs that are better than other commercial *** with CoCl_(2),metal-based PILs perform well,with superior conversion and KA oil *** interestingly,the catalyst created in this study features a malleable Co-N site,which may potentially have an impact on how oxygen species adsorb and desorb from the ***,the catalyst studied in this work is used as molecular oxygen for the selective oxidation of cyclohexane to produce KA oil,and its application prospect is promising.

关键词： Metal-PILs Cyclohexane oxidation C-H activation Co-N sites

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Numerical simulation of vortex breakdown in a cylindrical tank with rotating bottom and free surface using level set method

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Chinese Journal of Chemical engineering 2025年第1期77卷 293-300页

作者： Zepeng Zhao Qin Li Feng Ye Haoliang Wang Jianfeng Wang Hui Yu Xiangyang Li Chao Yang School of Chemical Engineering Sichuan UniversityChengdu 610065China CAS Key Laboratory of Green Process and Engineering State Key Laboratory of Petroleum Molecular&Process EngineeringInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China School of Ecology and Environment Zhengzhou UniversityZhengzhou 450001China

A cylindrical chamber with a rotating bottom holds significant potential for application in cell culture bioreactors due to its ability to generate more stable swirling *** order to control vortex breakdown within the chamber,this study first establishes a computational fluid dynamics simulation coupled with the level set *** by experimental results in literature,this method accurately simulates the position and shape of vortex breakdown,and also predicts the critical Reynolds numbers for the appearance and detachment of vortex breakdown bubbles from the ***,it precisely captures the gaseliquid interface and depicts the vortex breakdown phenomenon in the air above the liquid for the first ***,it predicts the impact of physical property of gaseliquid systems on vortex breakdown in response to significant changes in viscosity of microbial process systems.

关键词： Vortex breakdown Level set Microbial cultivation Micro-bioreactor

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Direct observation of ordered-disordered structural transition of MoS_(2)-confined ionic liquids

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Chinese Journal of Chemical engineering 2024年第8期72卷 126-132页

作者： Yumiao Lu Weilu Ding Kun Li Yanlei Wang Bobo Cao Ruirui He Hongyan He CAS Key Laboratory of Green Process and Engineering State Key Laboratory of Mesoscience and EngineeringBeijing Key Laboratory of Ionic Liquids Clean ProcessInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Longzihu New Energy Laboratory Zhengzhou Institute of Emerging Industrial TechnologyZhengzhou 450000China

Ionic liquids(ILs)are an emerging class of media of fundamental importance for chemical engineering,especially due to their interaction with solid ***,we explore the growth phenomenon of surface-confined ILs and reveal a peculiar structural transition behavior from order to disorder above a threshold *** behavior can be explained by the variation of interfacial forces with increasing distance from the solid *** structural observation of different ILs highlights the influence of the ionic structure on the growth ***,the length of the alkyl chain in the cation is found to be a determining factor for the ordering ***,the thermal stability of surface-confined ILs is investigated in depth by controlling annealing *** is found that the ordered monolayer ILs exhibit high robustness against high *** findings provide new perspectives on the properties of surface-confined ILs and open up potential avenues for manipulating the structures of nanometer-thick IL films for various applications.

关键词： Ionic liquids(ILs) Surface-confined ILs Structural transition Thermal stability Interfacial forces

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Synthesis of spherical nano-ZSM-5 zeolite with intergranular mesoporous for alkylation of ethylbenzene with ethanol to produce m-diethylbenzene

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Chinese Journal of Chemical engineering 2024年第3期67卷 298-309页

作者： Siyue Wang Jinhong Li Qingxin Xu Shengjie Song Yu'ni Jiang Lidong Chen Xin Shi Weiguo Cheng Faculty of Chemistry and Chemical Engineering Liaoning Normal UniversityDalian 110629China Beijing Key Laboratory of Ionic Liquids Clean Process Key Laboratory of Green Process and EngineeringInstitute of Process EngineeringChinese Academy of SciencesBeijing 100190China

Catalytic synthesis of m-diethylbenzene(m-DEB)through alkylation of ethylbenzene(EB)may be a promising alternative route in comparison with traditional rectification of mixed DEB,for which the top priority is to develop efficient and stable heterogeneous ***,the spherical nano-ZSM-5 zeolite with abundant intergranular mesoporous is synthesized by the seed-mediated growth method for alkylation of EB with ethanol to produce *** results show that the spherical nano-ZSM-5 zeolite exhibits better stability and higher alkylation activity at a lower temperature than those of commercial micropore *** then,the spherical nano-ZSM-5 is further modified by La_(2)O_(3) through acid treatment followed by immersion *** acid treatment causes nano-ZSM-5 to exhibit the increased pore size but decreased the acid sites,and subsequent La_(2)O_(3) loading reintroduces the weak acid *** a result,the HNO_(3)-La_(2)O_(3)-modified catalyst exhibits a slight increase in EB conversion and DEB yield in comparison with unmodified one,and meanwhile,it still maintains high m-DEB *** catalyst after acid treatment achieves higher catalytic stability besides maintaining the high alkylation activity of EB with *** present study on the spherical nano-HZSM-5 zeolite and its modification catalyst with excellent alkylation ability provides new insights into the production of mDEB.

关键词： Zeolite Modification Alkylation reaction m-diethylbenzene Catalyst Fixed-bed

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