The concept of liquid-solid hybrid catalyst that featuring a truly homogeneous liquid microenvironment together with insoluble solid characteristics has been established recently by our group,which enables us to conve...The concept of liquid-solid hybrid catalyst that featuring a truly homogeneous liquid microenvironment together with insoluble solid characteristics has been established recently by our group,which enables us to conveniently bridge the gap between homo-and heterogeneous catalysis.In this study,we extend this general concept to the confinement of molecular rhodium phosphine complexes,including Rh-TPPTS,Rh-TPPMS and Rh-SXP,for olefin hydroformylation reactions.A series of hybrid catalyst materials consisting a modulated liquid interior([BMIM]NTf_(2),[BMIM]PF_(6),[BMIM]BF_(4) or H_(2)O)and a permeable silica crust were fabricated through our developed Pickering emulsion-based method,showing 9.4–24.2-fold activity enhancement and significantly improved aldehyde selectivity(from 72.2%,61.8%to 86.6%)compared to their biphasic counterparts or traditional supported liquid phase system in the hydroformylation of 1-dodecene.Interestingly,the catalytic efficiency was demonstrated to be tunable by rationally engineering the thickness of porous crust and dimensions of the liquid pool.The thus-attained hybrid catalyst could also successfully catalyze the hydroformylation of a variety of olefin substrates and be recycled without a significant loss of activity for at least seven times.展开更多
Low-dimensional hybrid nanocrystals are newly emerging active photo catalysts for separating electron-hole pairs,but the instability and low quantum efficiency caused by particle aggregation and hybrid structure relax...Low-dimensional hybrid nanocrystals are newly emerging active photo catalysts for separating electron-hole pairs,but the instability and low quantum efficiency caused by particle aggregation and hybrid structure relaxation remain great challenges.To this end,herein we constructed amorphous FeO_(x)(A-FeO_(x))and crystalline LaFeO_(3)hybrids by a sol-gel method.The amorphous-crystalline hybrids,A-FeO_(x)/LaFeO_(3),not only improve the surface area and alter the band position,but also form numerous channels that are conducive to the transport of electrons and separation of electron-hole pairs,acting as microreactors.Photocatalytic tests show that the A-FeO_(x)/LaFeO_(3)is highly active for the degradation of various organic pollutants,with reaction rate constant of 1.19×10^(-2)min-1for cipro floxacin degradation,for example,which is 1.82 and 1.87 times higher than that of LaFeO_(3)and Fe_(2)O_(3)/LaFeO_(3),respectively,owing to the formation of microreactors between A-FeO_(x)and LaFeO_(3).Cycling tests show that the mate rial has good stability in the reaction,and trapping experiments demonstrate that the photo-induced holes are the main reactive species of the reaction.This work provides a novel and feasible insight into the design of high performance low-dimensional hybrid nanocatalysts for photocatalysis.展开更多
Fluorosurfactants play a crucial role in ensuring the stability and uniformity of droplet microreactors,which significantly broaden their applications in chemical and biological research.This review covers structure d...Fluorosurfactants play a crucial role in ensuring the stability and uniformity of droplet microreactors,which significantly broaden their applications in chemical and biological research.This review covers structure diversity and functional versatility of fluorosurfactants.Fluorosurfactants can be divided into two basic types according to their structure,linear and dendritic types,which both provides individual advantages.Linear fluorosurfactants are easily synthesized and commercially available,whereas dendritic fluorosurfactants have a branched structure that greatly reduces molecular cross-talk between droplets.Based on the application point of view,fluorosurfactants can be further classified into two categories:reactive and responsive fluorosurfactants.The hydrophilic head of reactive fluorosurfactants contains a reactive functional group,making them very useful in other applications,such as microcapsule preparation or protein crystallization.In contrast,responsive fluorosurfactants would change their properties with respect to external stimuli,such as temperature or light,making them perfect candidates for the on-demand control of droplet behavior.Development of these new classes of fluorosurfactants has expanded the capabilities and applications of droplet microreactors that enables interdisciplinary challenges to be solved.展开更多
Cyanoethylation of phenylamine is one of the important steps for the production of dicyanoethyl-based disperse dyes.However,the exothermic nature of this reaction and the inherent instability of intermittent dynamic o...Cyanoethylation of phenylamine is one of the important steps for the production of dicyanoethyl-based disperse dyes.However,the exothermic nature of this reaction and the inherent instability of intermittent dynamic operation pose challenges in achieving both high safety and reaction efficiency.In this study,a continuous cyanoethylation of phenylamine for synthesizing N,N-dicyanoethylaniline in a microreactor system has been developed.By optimizing the reaction conditions,the reaction time was significantly reduced from over 2 h in batch operation to approximately 14 min in the microreactor,while high conversion and selectivity were maintained.Based on the reaction network constructed,the reaction kinetics was established,and the kinetic parameters were then determined.These findings provide valuable insights into a controllable cyanoethylation reaction,which would be helpful for the design of efficient processes and optimization of reactors.展开更多
Mixing behavior is critical for enhancing the selectivity of fast chemical reactions in microreactors.A high Reynolds number(Re)improves the mixing rate and selectivity of the reactions,but some exceptions of increasi...Mixing behavior is critical for enhancing the selectivity of fast chemical reactions in microreactors.A high Reynolds number(Re)improves the mixing rate and selectivity of the reactions,but some exceptions of increasing side product yield with the higher Re have been reported.This study investigated the mixing uniformity in microreactors with in-line UV-vis spectroscopy to clarify the relationship between reaction selectivity and chaotic mixing with the higher Re.A colorization experiment of thymolphthalein in an acidic solution was conducted with an excess acid amount to the base to indicate a non-uniformly mixed region.Non-uniformity significantly increased with Re.At the same time,the degree of mixing,which was measured by a usual decolorization experiment,showed that the mixing rate increased with Re.The in-line analysis of the Villermaux-Dushman reaction during the mixing clarified that side product yield significantly increased with Re at around 300 and then decreased at around 1100.These results suggest the compensation effect between the mixing uniformity and mixing rate on the selectivity of the mixing-sensitive reactions.Faster mixing,characterized by a larger Re,can disturb mixing uniformity and,in some cases,decrease reaction selectivity.展开更多
Micromixing efficiency is an important parameter for evaluating the multiphase mass transfer performance and reaction efficiency of microreactors.In this work,the novel curved capillary reactor with different shapes w...Micromixing efficiency is an important parameter for evaluating the multiphase mass transfer performance and reaction efficiency of microreactors.In this work,the novel curved capillary reactor with different shapes was designed to generate Dean flow,which was used to enhance the liquid-liquid micromixing performance.The Villermaux-Dushman probe reaction was employed to characterize the micromixing performance in different curved capillary microreactors.The effects of experiment parameters such as liquid flow rate,inner diameter,tube length,and curve diameter on micromixing performance were systematically investigated.Under the optimal conditions,the minimum value of the segmentation factor XS was 0.008.It was worth noting that at the low Reynolds number(Re<30),the change of curved shape on the capillary microreactor can significantly improve the micromixing performance with XS reduced by 37.5%.Further,the correlations of segment index XS with dimensionless factor such as Reynolds number or Dean number were developed,which can be used to predict the liquid-liquid micromixing performance in capillary microreactors.展开更多
The development of efficient systems for the catalytic oxidation of 2-nitro-4-methylsulfonyltoluene(NMST)to 2-nitro-4-methylsulfonyl benzoic acid(NMSBA)with atmospheric air or molecular oxygen in alkaline medium prese...The development of efficient systems for the catalytic oxidation of 2-nitro-4-methylsulfonyltoluene(NMST)to 2-nitro-4-methylsulfonyl benzoic acid(NMSBA)with atmospheric air or molecular oxygen in alkaline medium presents a significant challenge for the chemical industry.Here,we report the synthesis of FeOOH/Fe_(3)O_(4)/metal-organic framework(MOF)polygonal mesopores microflower templated from a MIL-88B(Fe)at room temperature,which exposes polygonal mesopores with atomistic edge steps and lattice defects.The obtained FeOOH/Fe_(3)O_(4)/MOF catalyst was adsorbed onto glass beads and then introduced into the microchannel reactor.In the alkaline environment,oxygen was used as oxidant to catalyze the oxidation of NMST to NMSBA,showing impressive performance.This sustainable system utilizes oxygen as a clean oxidant in an inexpensive and environmentally friendly NaOH/methanol mixture.The position and type of substituent critically affect the products.Additionally,this sustainable protocol enabled gram-scale preparation of carboxylic acid and benzyl alcohol derivatives with high chemoselectivities.Finally,the reactions can be conducted in a pressure reactor,which can conserve oxygen and prevent solvent loss.Moreover,compared with the traditional batch reactor,the self-built microchannel reactor can accelerate the reaction rate,shorten the reaction time,and enhance the selectivity of catalytic oxidation reactions.This approach contributes to environmental protection and holds potential for industrial applications.展开更多
This paper describes the application of ultrasound waves on hydrodynamics and mass transfer characteristics in the gas–liquid flow in a T-shape microreactor with a diameter of 800 μm. A 1.7 MHz piezoelectric transdu...This paper describes the application of ultrasound waves on hydrodynamics and mass transfer characteristics in the gas–liquid flow in a T-shape microreactor with a diameter of 800 μm. A 1.7 MHz piezoelectric transducer(PZT) was employed to induce the vibration in this microreactor. Liquid side volumetric mass transfer coefficients were measured by physical and chemical methods of CO_2 absorption into water and Na OH solution. The approach of absorption of CO_2 into a 1 mol·L^(-1) Na OH solution was used for analysis of interfacial areas. With the help of a photography system, the fluid flow patterns inside the microreactor were analyzed. The effects of superficial liquid velocity, initial concentration of Na OH, superficial CO_2 gas velocity and length of microreactor on the mass transfer rate were investigated. The comparison between sonicated and plain microreactors(microreactor with and without ultrasound) shows that the ultrasound wave irradiation has a significant effect on kLa and interfacial area at various operational conditions. For the microreactor length of 12 cm, ultrasound waves improved kLa and interfacial area about 21% and 22%, respectively. From this study, it can be concluded that ultrasound wave irradiation in microreactor has a great effect on the mass transfer rate. This study suggests a new enhancement technique to establish high interfacial area and kLa in microreactors.展开更多
Gas-liquid-liquid three-phase slug flow was generated in both hydrophilic and hydrophobic microreactors with double T-junctions.The bubble-droplet relative movement and the local mass transfer within the continuous sl...Gas-liquid-liquid three-phase slug flow was generated in both hydrophilic and hydrophobic microreactors with double T-junctions.The bubble-droplet relative movement and the local mass transfer within the continuous slug and the dispersed droplet were investigated.It was found that bubbles moved faster than droplets under low capillary number(Ca),while droplets moved faster upon the increase of Ca due to the increased inertia.For the first time,we observed that the increased viscosity of droplets fastened the droplet movement.The mass transfer in the continuous slug was dominated by convection,leading to nearly constant global mass transfer coefficient(k_(L)a);while that in the dispersed droplet was dominated by diffusion,resulting in k_(L) decreasing along the channel.Such features are analogical to the corresponding gas-liquid or liquid-liquid two-phase slug flow,but the formation of bubble-droplet clusters caused by relative movement lowered the absolute mass transfer coefficient.These results provide insights for the precise manipulation of gas-liquid-liquid slug flow in microreactors towards process optimization.展开更多
Ultra-high-purity silicon tetrachloride(SiCl4)is demanded as an electronic-grade chemical to meet the stringent requirements of the rapidly developing semiconductor industry.The high requirement for ultra-high-purity ...Ultra-high-purity silicon tetrachloride(SiCl4)is demanded as an electronic-grade chemical to meet the stringent requirements of the rapidly developing semiconductor industry.The high requirement for ultra-high-purity SiCl4 has created the need for a high-efficient process for reducing energy consumption as well as satisfying product quality.In this paper,a mass of production technology of ultra-high-purity SiCl4 was successfully developed through chlorination reaction in the ultraviolet(UV)-based photo microreactor coupled with the distillation process.The influences of key operational parameters,including temperature,pressure,UV wavelength and light intensity on the product quality,especially for hydrogen-containing impurities,were quantified by the infrared transmittance of Fourier transform infrared spectroscopy(FT-IR)at 2185 cm^-1and 2160 cm^-1indicating that chara cteristic vib rational modes of Si-H bonds,as well as the operating conditions of distillation were also investigated as key factors for metal impurities removing.The advanced intensification of SiCl4 manufactured by the integration of photo microreactor and distillation achieves the products with superior specifications higher than the standard commercial products.展开更多
Fixed-bed reactors for the partial oxidation of methane to produce synthetic gas still pose hotspot problems. An alternative reactor, which is known as the shell-and-tube-typed microreactor, has been developed to reso...Fixed-bed reactors for the partial oxidation of methane to produce synthetic gas still pose hotspot problems. An alternative reactor, which is known as the shell-and-tube-typed microreactor, has been developed to resolve these problems. The microreactor consists of a 1 cm outside-diameter, 0.8 cm insidediameter and 11 cm length tube, and a 1.8 cm inside-diameter shell. The tube is made of dense alumina and the shell is made of quartz. Two different methods dip and spray coating were performed to line the tube side with the LaNixOy catalyst. Combustion and reforming reactions take place simultaneously in this reactor. Methane is oxidized in the tube side to produce flue gases （CO2 and H2O） which flow counter-currently and react with the remaining methane in the shell side to yield synthesis gas. The methane conversion using the higher-loading catalyst spray-coated tube reaches 97% at 700 ℃, whereas that using the lower-loading catalyst dip-coated tube reaches only 7.78% because of poor adhesion between the catalyst film and the alumina support. The turnover frequencies （TOFs） using the catalyst spray-and dip-coated tubes are 5.75×10^-5 and 2.24×10^-5 mol/gcat· s, respectively. The catalyst spray-coated at 900 ℃ provides better performance than that at 1250 ℃ because sintering reduces the surface-area. The hydrogen to carbon monoxide ratio produced by the spray-coated catalyst is greater than the stoichiometric ratio, which is caused by carbon deposition through methane cracking or the Boudouard reaction.展开更多
With global warming,the demand for diversified energy sources has increased significantly.Transportable microreactors are important potential supplements to the global power market and are a promising development dire...With global warming,the demand for diversified energy sources has increased significantly.Transportable microreactors are important potential supplements to the global power market and are a promising development direction.This paper describes a 5 MW integrated long-life S-CO_(2)cooled vehicular microreactor(VMR)design based on tristructural isotropic(TRISO)fuel particles that aims to provide electricity for industrial power facilities,remote mines,and remote mountainous areas that are not connected to central power grids.First,to facilitate transportation,flexible deployment,and simplified operation and maintenance requirements,the VMR core and auxiliary system were designed to be reasonably small and as simple as possible.Second,the TRISO fuel particles used in the proposed VMR offer excellent properties,such as high inherent security and nonproliferation,which are vital for reactors in remote areas.In addition,a long core lifetime was achieved using the compact core design and enhanced fuel loading capacity,which is challenging when using TRISO as fuel.Finally,to make the VMR economically competitive in terms of improved neutron performance and fuel efficiency compared to similar designs,large-size TRISO particles and tube-in-duct fuel assembly were utilized and different core configurations were schemed and simulated to obtain the design that best satisfied the proposed criteria.The lifetime and burnup in the final optimized VMR were satisfactory at 21 years and43.9 MWd/kgU,respectively,with an adequate shutdown margin and excellent safety parameters to ensure safe operation.展开更多
A new microreactor with continuous serially connected micromixers(CSCM)was tailored for the coprecipitation process to synthesize Fe_(3)O_(4) nanoparticles.Numerical simulation reveals that the two types of CSCM micro...A new microreactor with continuous serially connected micromixers(CSCM)was tailored for the coprecipitation process to synthesize Fe_(3)O_(4) nanoparticles.Numerical simulation reveals that the two types of CSCM microchannels(V-typed and U-typed)proposed in this work exhibited markedly better mixing performances than the Zigzag and capillary microchannels due to the promotion of Dean vortices.Complete mixing was achieved in the V-typed microchannel in 2.7 s at an inlet Reynolds number of 27.Fe_(3)O_(4) nanoparticles synthesized in a planar glass microreactor with the V-typed microchannel,possessing an average size of 9.3 nm and exhibiting superparamagnetism,had obviously better dispersity and uniformity and higher crystallinity than those obtained in the capillary microreactor.The new CSCM microreactor developed in this work can act as a potent device to intensify the synthesis of similar inorganic nanoparticles via multistep chemical precipitation processes.展开更多
For the synthesis of AgInS_2 quantum dots(QDs), a suitable temperature is extremely important for control of the size, shape and fluorescence properties of QDs. Most of synthesis methods for AgInS_2 QDs are based on b...For the synthesis of AgInS_2 quantum dots(QDs), a suitable temperature is extremely important for control of the size, shape and fluorescence properties of QDs. Most of synthesis methods for AgInS_2 QDs are based on batch reactors, which bring uneven distribution of temperature, affecting their fluorescence properties and size uniformity. Here we designed a droplet microreactor with a temperature-controllable region, and successfully synthesized water-soluble AgInS_2 QDs. By accurately controlling temperature,we also studied how the reaction temperature affected the fluorescence properties of AgInS_2 QDs. The results showed that with the increasing of reaction temperature, the QDs size increased and the fluorescence peak constantly red-shifted along with enhanced fluorescence intensity. Based on the droplet microreactor, we could achieve more appropriate reaction condition to synthesize AgInS_2 QDs with higher fluorescence quantum yield(QY) and intensity.展开更多
Aqueous phase synthesized ternary I-III-VI_(2) Quantum dots(QDs)are getting more and more attention in biology researches,for their good biocompatibility and easy-to-adjust fluorescence properties.However,the quantum ...Aqueous phase synthesized ternary I-III-VI_(2) Quantum dots(QDs)are getting more and more attention in biology researches,for their good biocompatibility and easy-to-adjust fluorescence properties.However,the quantum yield(QY)of these aqueous phase synthesized QDs are often pretty low,which seriously hindered their further applications in this field.In general,the ripening of the QDs helps to enhance their QY,closely related to the ripening temperature.But it is still hard to precisely control the fluorescence performance of the QDs products,due to the difficulties in precise temperature control and cumbersome temperature adjusting operations in batch reactors.Here we proposed an integrated droplet microfluidic chip for the automated and successive AgInS_(2)QDs synthesis and ripening,with both temperatures controlled independently,precisely but easily.Taking advantage of the space-time transformation of the droplet microfluidic chips,the suitable temperature combination for Ag In S_(2)QDs synthesis and ripening was studied,and the high-performance AgInS_(2)QDs were obtained.In addition,the reason for the decrease of QY of AgInS_(2)QDs at higher ripening temperature was also explored.展开更多
In this work, a liquid-gas heterogeneous microreactor was developed for investigating continuous crystallization of dolutegravir sodium(DTG), as well as revealing reaction kinetics and mixing mechanism with 3-min data...In this work, a liquid-gas heterogeneous microreactor was developed for investigating continuous crystallization of dolutegravir sodium(DTG), as well as revealing reaction kinetics and mixing mechanism with 3-min data acquisition. The reaction kinetics models were established by visually recording the concentration variation of reactants over time in the microchannel via adding pH-sensitive fluorescent dye. The mixing intensification mechanism of liquid-gas flow was quantified through the fluorescent signal to indicate mixing process, demonstrating an outstanding mixing performance with a mixing time less than 0.1 s. Compared with batch crystallization, continuous synthesis of dolutegravir sodium using liquid-gas heterogenous microreactor optimizes crystal distribution size, and successfully modifies the crystal morphology in needle-like habit instead of rod-like habit. The microreactor continuous crystallization can run for 5 h without crystal blockage and achieve D90 of DTG less than 30 μm. This work provides a feasible approach for continuously synthesizing dolutegravir sodium, and can optimize the existing pharmaceutical crystallization.展开更多
The hydrogenation of hydrogen peroxide is an unwanted side reaction in the direct synthesis of hydrogen peroxide and remains a problem to solve.The mechanism of this reaction has been studied with batch reactors but t...The hydrogenation of hydrogen peroxide is an unwanted side reaction in the direct synthesis of hydrogen peroxide and remains a problem to solve.The mechanism of this reaction has been studied with batch reactors but the slow heat and mass transfer in batch reactors hindered the understanding of its intrinsic kinetics.In this study,a microreactor is employed to investigate the parameters that influence the hydrogenation reaction,including flow rate,channel length,hydrogen pressure,solvent composition,and initial hydrogen peroxide concentration.The activity of different catalysts was compared and the hydrogenation law was confirmed,providing guiding information to better control the hydrogenation process.展开更多
An easy method is presented to fabricate monodisperse magnetic macroporous polymer beads（MMPBs）. Waterin-oil high internal phase emulsion（HIPE） is prepared by emulsifying aqueous iron ions solution in an oil phase...An easy method is presented to fabricate monodisperse magnetic macroporous polymer beads（MMPBs）. Waterin-oil high internal phase emulsion（HIPE） is prepared by emulsifying aqueous iron ions solution in an oil phase containing monomers. The HIPE is introduced into a simple microfluidic device to fabricate monodisperse（water-in-oil）-in-water double emulsion droplets. The droplets serve as microreactors to synthesize Fe3O4 nanoparticles and are on-line polymerized to form MMPBs. The prepared MMPBs display uniform size, interconnected porous structure, superparamagnetic behavior and uniform distribution of Fe3O4 in polymer matrix. The MMPBs are characterized by scanning electron microscopy（SEM）, Fourier transform infrared spectroscopy（FTIR）, X-ray diffraction（XRD）, transmission electron microscopy（TEM）, vibrating sample magnetometry（VSM）. We believe that this method is a universal technique in preparing macroporous nanocomposite beads.展开更多
In this paper, operator-based nonlinear water temperature control for a group of three connected microreactors actuated by Peltier devices is proposed. To control the water temperature of tube in the microreactor, the...In this paper, operator-based nonlinear water temperature control for a group of three connected microreactors actuated by Peltier devices is proposed. To control the water temperature of tube in the microreactor, the temperature change of aluminum effects is considered. Therefore, the temperature change of aluminum becomes the part of an input of the tube. First, nonlinear thermal models of aluminum plates and tubes that structure the microreactor are obtained. Then, an operator based nonlinear water temperature control system for the microreactor is designed. Finally, the effectiveness of the proposed models and methods is confirmed by simulation and experimental results.展开更多
In this study, the laminated porous metal fiber sintered felt(PMFSF) functioning as catalyst support was used in a cylindrical methanol steam reforming(MSR) microreactor for hydrogen production. The PMFSF was fabricat...In this study, the laminated porous metal fiber sintered felt(PMFSF) functioning as catalyst support was used in a cylindrical methanol steam reforming(MSR) microreactor for hydrogen production. The PMFSF was fabricated by the low temperature solid-phase sintering method using metal fibers such as copper fibers and aluminum fibers which are obtained by the multi-tooth cutting method. The two-layer impregnation method was employed to coat Cu/Zn/Al/Zr catalyst on the PMFSF. The effect of fiber material, uniform porosity and gradient porosity on the performance of methano steam reforming microreactor was studied by varying the gas hourly space velocity(GHSV) and reaction temperature. Our results showed that the loading strength of porous copper fiber sintered felt(PCFSF) was better than porous aluminum fiber sintered felt(PAFSF). Under the same reaction conditions, the PCFSF showed higher methanol conversion and more H_2 output than PAFSF. Moreover, the gradient porosity(Type 5: 90%×80%×70%) of PMFSF used as the catalyst support in microreactor demonstrated a best reaction performance for hydrogen production.展开更多
文摘The concept of liquid-solid hybrid catalyst that featuring a truly homogeneous liquid microenvironment together with insoluble solid characteristics has been established recently by our group,which enables us to conveniently bridge the gap between homo-and heterogeneous catalysis.In this study,we extend this general concept to the confinement of molecular rhodium phosphine complexes,including Rh-TPPTS,Rh-TPPMS and Rh-SXP,for olefin hydroformylation reactions.A series of hybrid catalyst materials consisting a modulated liquid interior([BMIM]NTf_(2),[BMIM]PF_(6),[BMIM]BF_(4) or H_(2)O)and a permeable silica crust were fabricated through our developed Pickering emulsion-based method,showing 9.4–24.2-fold activity enhancement and significantly improved aldehyde selectivity(from 72.2%,61.8%to 86.6%)compared to their biphasic counterparts or traditional supported liquid phase system in the hydroformylation of 1-dodecene.Interestingly,the catalytic efficiency was demonstrated to be tunable by rationally engineering the thickness of porous crust and dimensions of the liquid pool.The thus-attained hybrid catalyst could also successfully catalyze the hydroformylation of a variety of olefin substrates and be recycled without a significant loss of activity for at least seven times.
基金Project supported by the National Natural Science Foundation of China(42277485,21976141)the Department of Science and Technology of Hubei Province(2021CFA034)the Knowledge Innovation Program of Wuhan-Shuguang Project(2023020201020369)。
文摘Low-dimensional hybrid nanocrystals are newly emerging active photo catalysts for separating electron-hole pairs,but the instability and low quantum efficiency caused by particle aggregation and hybrid structure relaxation remain great challenges.To this end,herein we constructed amorphous FeO_(x)(A-FeO_(x))and crystalline LaFeO_(3)hybrids by a sol-gel method.The amorphous-crystalline hybrids,A-FeO_(x)/LaFeO_(3),not only improve the surface area and alter the band position,but also form numerous channels that are conducive to the transport of electrons and separation of electron-hole pairs,acting as microreactors.Photocatalytic tests show that the A-FeO_(x)/LaFeO_(3)is highly active for the degradation of various organic pollutants,with reaction rate constant of 1.19×10^(-2)min-1for cipro floxacin degradation,for example,which is 1.82 and 1.87 times higher than that of LaFeO_(3)and Fe_(2)O_(3)/LaFeO_(3),respectively,owing to the formation of microreactors between A-FeO_(x)and LaFeO_(3).Cycling tests show that the mate rial has good stability in the reaction,and trapping experiments demonstrate that the photo-induced holes are the main reactive species of the reaction.This work provides a novel and feasible insight into the design of high performance low-dimensional hybrid nanocatalysts for photocatalysis.
基金support of the National Key Research and Development Program of China(2021YFC2104300)the National Natural Science Foundation of China(T2322011,22308146,22278214)the support of the State Key Laboratory of Materials-Oriented Chemical Engineering(SKL-MCE-22A06,KL20-02).
文摘Fluorosurfactants play a crucial role in ensuring the stability and uniformity of droplet microreactors,which significantly broaden their applications in chemical and biological research.This review covers structure diversity and functional versatility of fluorosurfactants.Fluorosurfactants can be divided into two basic types according to their structure,linear and dendritic types,which both provides individual advantages.Linear fluorosurfactants are easily synthesized and commercially available,whereas dendritic fluorosurfactants have a branched structure that greatly reduces molecular cross-talk between droplets.Based on the application point of view,fluorosurfactants can be further classified into two categories:reactive and responsive fluorosurfactants.The hydrophilic head of reactive fluorosurfactants contains a reactive functional group,making them very useful in other applications,such as microcapsule preparation or protein crystallization.In contrast,responsive fluorosurfactants would change their properties with respect to external stimuli,such as temperature or light,making them perfect candidates for the on-demand control of droplet behavior.Development of these new classes of fluorosurfactants has expanded the capabilities and applications of droplet microreactors that enables interdisciplinary challenges to be solved.
基金the financial supports from National Natural Science Foundation of China(22378344,22208278)Natural Science Foundation of Shandong Province(ZR2023MB120,ZR2023QB152)Youth Innovation Team Plan of Shandong Province(2022KJ270)。
文摘Cyanoethylation of phenylamine is one of the important steps for the production of dicyanoethyl-based disperse dyes.However,the exothermic nature of this reaction and the inherent instability of intermittent dynamic operation pose challenges in achieving both high safety and reaction efficiency.In this study,a continuous cyanoethylation of phenylamine for synthesizing N,N-dicyanoethylaniline in a microreactor system has been developed.By optimizing the reaction conditions,the reaction time was significantly reduced from over 2 h in batch operation to approximately 14 min in the microreactor,while high conversion and selectivity were maintained.Based on the reaction network constructed,the reaction kinetics was established,and the kinetic parameters were then determined.These findings provide valuable insights into a controllable cyanoethylation reaction,which would be helpful for the design of efficient processes and optimization of reactors.
基金the support of JSPS KAKENHI(21H05083)the Cooperative Research Program of the Network Joint Research Center for Materials and Devices,which was supported by the Ministry of Education,Culture,Sports,Science,and Technology(MEXT),JapanAUN/SEED-Net(BUU REd-UC 2301)for Research and Education Grant for the University Consortium(consortium name:CES-CHEM)。
文摘Mixing behavior is critical for enhancing the selectivity of fast chemical reactions in microreactors.A high Reynolds number(Re)improves the mixing rate and selectivity of the reactions,but some exceptions of increasing side product yield with the higher Re have been reported.This study investigated the mixing uniformity in microreactors with in-line UV-vis spectroscopy to clarify the relationship between reaction selectivity and chaotic mixing with the higher Re.A colorization experiment of thymolphthalein in an acidic solution was conducted with an excess acid amount to the base to indicate a non-uniformly mixed region.Non-uniformity significantly increased with Re.At the same time,the degree of mixing,which was measured by a usual decolorization experiment,showed that the mixing rate increased with Re.The in-line analysis of the Villermaux-Dushman reaction during the mixing clarified that side product yield significantly increased with Re at around 300 and then decreased at around 1100.These results suggest the compensation effect between the mixing uniformity and mixing rate on the selectivity of the mixing-sensitive reactions.Faster mixing,characterized by a larger Re,can disturb mixing uniformity and,in some cases,decrease reaction selectivity.
基金supports of National Natural Science Foundation of China(22308057)Outstanding Talent Introduction Funds from Fuzhou University(0040-511175)Fuzhou University Testing Fund of precious apparatus(2023T003).
文摘Micromixing efficiency is an important parameter for evaluating the multiphase mass transfer performance and reaction efficiency of microreactors.In this work,the novel curved capillary reactor with different shapes was designed to generate Dean flow,which was used to enhance the liquid-liquid micromixing performance.The Villermaux-Dushman probe reaction was employed to characterize the micromixing performance in different curved capillary microreactors.The effects of experiment parameters such as liquid flow rate,inner diameter,tube length,and curve diameter on micromixing performance were systematically investigated.Under the optimal conditions,the minimum value of the segmentation factor XS was 0.008.It was worth noting that at the low Reynolds number(Re<30),the change of curved shape on the capillary microreactor can significantly improve the micromixing performance with XS reduced by 37.5%.Further,the correlations of segment index XS with dimensionless factor such as Reynolds number or Dean number were developed,which can be used to predict the liquid-liquid micromixing performance in capillary microreactors.
基金supported by the National Natural Science Foundation of China(22078251)Hubei Province Key Research and Development Program(2023DJC167)the research project of Hubei Provincial Department of Education(D20191504).
文摘The development of efficient systems for the catalytic oxidation of 2-nitro-4-methylsulfonyltoluene(NMST)to 2-nitro-4-methylsulfonyl benzoic acid(NMSBA)with atmospheric air or molecular oxygen in alkaline medium presents a significant challenge for the chemical industry.Here,we report the synthesis of FeOOH/Fe_(3)O_(4)/metal-organic framework(MOF)polygonal mesopores microflower templated from a MIL-88B(Fe)at room temperature,which exposes polygonal mesopores with atomistic edge steps and lattice defects.The obtained FeOOH/Fe_(3)O_(4)/MOF catalyst was adsorbed onto glass beads and then introduced into the microchannel reactor.In the alkaline environment,oxygen was used as oxidant to catalyze the oxidation of NMST to NMSBA,showing impressive performance.This sustainable system utilizes oxygen as a clean oxidant in an inexpensive and environmentally friendly NaOH/methanol mixture.The position and type of substituent critically affect the products.Additionally,this sustainable protocol enabled gram-scale preparation of carboxylic acid and benzyl alcohol derivatives with high chemoselectivities.Finally,the reactions can be conducted in a pressure reactor,which can conserve oxygen and prevent solvent loss.Moreover,compared with the traditional batch reactor,the self-built microchannel reactor can accelerate the reaction rate,shorten the reaction time,and enhance the selectivity of catalytic oxidation reactions.This approach contributes to environmental protection and holds potential for industrial applications.
文摘This paper describes the application of ultrasound waves on hydrodynamics and mass transfer characteristics in the gas–liquid flow in a T-shape microreactor with a diameter of 800 μm. A 1.7 MHz piezoelectric transducer(PZT) was employed to induce the vibration in this microreactor. Liquid side volumetric mass transfer coefficients were measured by physical and chemical methods of CO_2 absorption into water and Na OH solution. The approach of absorption of CO_2 into a 1 mol·L^(-1) Na OH solution was used for analysis of interfacial areas. With the help of a photography system, the fluid flow patterns inside the microreactor were analyzed. The effects of superficial liquid velocity, initial concentration of Na OH, superficial CO_2 gas velocity and length of microreactor on the mass transfer rate were investigated. The comparison between sonicated and plain microreactors(microreactor with and without ultrasound) shows that the ultrasound wave irradiation has a significant effect on kLa and interfacial area at various operational conditions. For the microreactor length of 12 cm, ultrasound waves improved kLa and interfacial area about 21% and 22%, respectively. From this study, it can be concluded that ultrasound wave irradiation in microreactor has a great effect on the mass transfer rate. This study suggests a new enhancement technique to establish high interfacial area and kLa in microreactors.
基金the financial support for this work from National Natural Science Foundation of China(21991103,92034303,91634204)。
文摘Gas-liquid-liquid three-phase slug flow was generated in both hydrophilic and hydrophobic microreactors with double T-junctions.The bubble-droplet relative movement and the local mass transfer within the continuous slug and the dispersed droplet were investigated.It was found that bubbles moved faster than droplets under low capillary number(Ca),while droplets moved faster upon the increase of Ca due to the increased inertia.For the first time,we observed that the increased viscosity of droplets fastened the droplet movement.The mass transfer in the continuous slug was dominated by convection,leading to nearly constant global mass transfer coefficient(k_(L)a);while that in the dispersed droplet was dominated by diffusion,resulting in k_(L) decreasing along the channel.Such features are analogical to the corresponding gas-liquid or liquid-liquid two-phase slug flow,but the formation of bubble-droplet clusters caused by relative movement lowered the absolute mass transfer coefficient.These results provide insights for the precise manipulation of gas-liquid-liquid slug flow in microreactors towards process optimization.
基金financial support from Industry Base Project supported by Ministry of Industry and Information Technology(0714-EMTC02-5593/13)Scientific Research and Development of Henan province(174200510014)。
文摘Ultra-high-purity silicon tetrachloride(SiCl4)is demanded as an electronic-grade chemical to meet the stringent requirements of the rapidly developing semiconductor industry.The high requirement for ultra-high-purity SiCl4 has created the need for a high-efficient process for reducing energy consumption as well as satisfying product quality.In this paper,a mass of production technology of ultra-high-purity SiCl4 was successfully developed through chlorination reaction in the ultraviolet(UV)-based photo microreactor coupled with the distillation process.The influences of key operational parameters,including temperature,pressure,UV wavelength and light intensity on the product quality,especially for hydrogen-containing impurities,were quantified by the infrared transmittance of Fourier transform infrared spectroscopy(FT-IR)at 2185 cm^-1and 2160 cm^-1indicating that chara cteristic vib rational modes of Si-H bonds,as well as the operating conditions of distillation were also investigated as key factors for metal impurities removing.The advanced intensification of SiCl4 manufactured by the integration of photo microreactor and distillation achieves the products with superior specifications higher than the standard commercial products.
文摘Fixed-bed reactors for the partial oxidation of methane to produce synthetic gas still pose hotspot problems. An alternative reactor, which is known as the shell-and-tube-typed microreactor, has been developed to resolve these problems. The microreactor consists of a 1 cm outside-diameter, 0.8 cm insidediameter and 11 cm length tube, and a 1.8 cm inside-diameter shell. The tube is made of dense alumina and the shell is made of quartz. Two different methods dip and spray coating were performed to line the tube side with the LaNixOy catalyst. Combustion and reforming reactions take place simultaneously in this reactor. Methane is oxidized in the tube side to produce flue gases （CO2 and H2O） which flow counter-currently and react with the remaining methane in the shell side to yield synthesis gas. The methane conversion using the higher-loading catalyst spray-coated tube reaches 97% at 700 ℃, whereas that using the lower-loading catalyst dip-coated tube reaches only 7.78% because of poor adhesion between the catalyst film and the alumina support. The turnover frequencies （TOFs） using the catalyst spray-and dip-coated tubes are 5.75×10^-5 and 2.24×10^-5 mol/gcat· s, respectively. The catalyst spray-coated at 900 ℃ provides better performance than that at 1250 ℃ because sintering reduces the surface-area. The hydrogen to carbon monoxide ratio produced by the spray-coated catalyst is greater than the stoichiometric ratio, which is caused by carbon deposition through methane cracking or the Boudouard reaction.
基金supported by the National Natural Science Foundation of China(No.12005290)the Chinese TMSR Strategic Pioneer Science and Technology Project(No.XDA02010000)Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2020261)。
文摘With global warming,the demand for diversified energy sources has increased significantly.Transportable microreactors are important potential supplements to the global power market and are a promising development direction.This paper describes a 5 MW integrated long-life S-CO_(2)cooled vehicular microreactor(VMR)design based on tristructural isotropic(TRISO)fuel particles that aims to provide electricity for industrial power facilities,remote mines,and remote mountainous areas that are not connected to central power grids.First,to facilitate transportation,flexible deployment,and simplified operation and maintenance requirements,the VMR core and auxiliary system were designed to be reasonably small and as simple as possible.Second,the TRISO fuel particles used in the proposed VMR offer excellent properties,such as high inherent security and nonproliferation,which are vital for reactors in remote areas.In addition,a long core lifetime was achieved using the compact core design and enhanced fuel loading capacity,which is challenging when using TRISO as fuel.Finally,to make the VMR economically competitive in terms of improved neutron performance and fuel efficiency compared to similar designs,large-size TRISO particles and tube-in-duct fuel assembly were utilized and different core configurations were schemed and simulated to obtain the design that best satisfied the proposed criteria.The lifetime and burnup in the final optimized VMR were satisfactory at 21 years and43.9 MWd/kgU,respectively,with an adequate shutdown margin and excellent safety parameters to ensure safe operation.
基金the financial support from the National Natural Science Foundation of China(21808059)the Fundamental Research Funds for the Central Universities(JKA01221712).
文摘A new microreactor with continuous serially connected micromixers(CSCM)was tailored for the coprecipitation process to synthesize Fe_(3)O_(4) nanoparticles.Numerical simulation reveals that the two types of CSCM microchannels(V-typed and U-typed)proposed in this work exhibited markedly better mixing performances than the Zigzag and capillary microchannels due to the promotion of Dean vortices.Complete mixing was achieved in the V-typed microchannel in 2.7 s at an inlet Reynolds number of 27.Fe_(3)O_(4) nanoparticles synthesized in a planar glass microreactor with the V-typed microchannel,possessing an average size of 9.3 nm and exhibiting superparamagnetism,had obviously better dispersity and uniformity and higher crystallinity than those obtained in the capillary microreactor.The new CSCM microreactor developed in this work can act as a potent device to intensify the synthesis of similar inorganic nanoparticles via multistep chemical precipitation processes.
基金supported by the National Natural Science Foundation of China (Nos. 21375100, 21775111)the National Science and Technology Major Project of China (No. 2018ZX10301405)
文摘For the synthesis of AgInS_2 quantum dots(QDs), a suitable temperature is extremely important for control of the size, shape and fluorescence properties of QDs. Most of synthesis methods for AgInS_2 QDs are based on batch reactors, which bring uneven distribution of temperature, affecting their fluorescence properties and size uniformity. Here we designed a droplet microreactor with a temperature-controllable region, and successfully synthesized water-soluble AgInS_2 QDs. By accurately controlling temperature,we also studied how the reaction temperature affected the fluorescence properties of AgInS_2 QDs. The results showed that with the increasing of reaction temperature, the QDs size increased and the fluorescence peak constantly red-shifted along with enhanced fluorescence intensity. Based on the droplet microreactor, we could achieve more appropriate reaction condition to synthesize AgInS_2 QDs with higher fluorescence quantum yield(QY) and intensity.
基金supported by the National Natural Science Foundation of China(Nos.22074107,21775111)。
文摘Aqueous phase synthesized ternary I-III-VI_(2) Quantum dots(QDs)are getting more and more attention in biology researches,for their good biocompatibility and easy-to-adjust fluorescence properties.However,the quantum yield(QY)of these aqueous phase synthesized QDs are often pretty low,which seriously hindered their further applications in this field.In general,the ripening of the QDs helps to enhance their QY,closely related to the ripening temperature.But it is still hard to precisely control the fluorescence performance of the QDs products,due to the difficulties in precise temperature control and cumbersome temperature adjusting operations in batch reactors.Here we proposed an integrated droplet microfluidic chip for the automated and successive AgInS_(2)QDs synthesis and ripening,with both temperatures controlled independently,precisely but easily.Taking advantage of the space-time transformation of the droplet microfluidic chips,the suitable temperature combination for Ag In S_(2)QDs synthesis and ripening was studied,and the high-performance AgInS_(2)QDs were obtained.In addition,the reason for the decrease of QY of AgInS_(2)QDs at higher ripening temperature was also explored.
基金supported by the Natural Science Foundation of the Science and Technology Commission of Shanghai Municipality(No.19ZR1472200)National Natural Science Foundation of China(No.22178072)。
文摘In this work, a liquid-gas heterogeneous microreactor was developed for investigating continuous crystallization of dolutegravir sodium(DTG), as well as revealing reaction kinetics and mixing mechanism with 3-min data acquisition. The reaction kinetics models were established by visually recording the concentration variation of reactants over time in the microchannel via adding pH-sensitive fluorescent dye. The mixing intensification mechanism of liquid-gas flow was quantified through the fluorescent signal to indicate mixing process, demonstrating an outstanding mixing performance with a mixing time less than 0.1 s. Compared with batch crystallization, continuous synthesis of dolutegravir sodium using liquid-gas heterogenous microreactor optimizes crystal distribution size, and successfully modifies the crystal morphology in needle-like habit instead of rod-like habit. The microreactor continuous crystallization can run for 5 h without crystal blockage and achieve D90 of DTG less than 30 μm. This work provides a feasible approach for continuously synthesizing dolutegravir sodium, and can optimize the existing pharmaceutical crystallization.
基金supported by the National Natural Science Foundation of China (Grant No. 21908249 and No. 22208382)the support received from the Chinese State Key Laboratory of Chemical Safety。
文摘The hydrogenation of hydrogen peroxide is an unwanted side reaction in the direct synthesis of hydrogen peroxide and remains a problem to solve.The mechanism of this reaction has been studied with batch reactors but the slow heat and mass transfer in batch reactors hindered the understanding of its intrinsic kinetics.In this study,a microreactor is employed to investigate the parameters that influence the hydrogenation reaction,including flow rate,channel length,hydrogen pressure,solvent composition,and initial hydrogen peroxide concentration.The activity of different catalysts was compared and the hydrogenation law was confirmed,providing guiding information to better control the hydrogenation process.
文摘An easy method is presented to fabricate monodisperse magnetic macroporous polymer beads（MMPBs）. Waterin-oil high internal phase emulsion（HIPE） is prepared by emulsifying aqueous iron ions solution in an oil phase containing monomers. The HIPE is introduced into a simple microfluidic device to fabricate monodisperse（water-in-oil）-in-water double emulsion droplets. The droplets serve as microreactors to synthesize Fe3O4 nanoparticles and are on-line polymerized to form MMPBs. The prepared MMPBs display uniform size, interconnected porous structure, superparamagnetic behavior and uniform distribution of Fe3O4 in polymer matrix. The MMPBs are characterized by scanning electron microscopy（SEM）, Fourier transform infrared spectroscopy（FTIR）, X-ray diffraction（XRD）, transmission electron microscopy（TEM）, vibrating sample magnetometry（VSM）. We believe that this method is a universal technique in preparing macroporous nanocomposite beads.
文摘In this paper, operator-based nonlinear water temperature control for a group of three connected microreactors actuated by Peltier devices is proposed. To control the water temperature of tube in the microreactor, the temperature change of aluminum effects is considered. Therefore, the temperature change of aluminum becomes the part of an input of the tube. First, nonlinear thermal models of aluminum plates and tubes that structure the microreactor are obtained. Then, an operator based nonlinear water temperature control system for the microreactor is designed. Finally, the effectiveness of the proposed models and methods is confirmed by simulation and experimental results.
基金supported by the Natural Science Fundation of Fujian Province of China (No. 2017J06015)the Foundation of Public Welfare Research and Capacity Building in Guangdong Province (No. 2014A010106002)+2 种基金the State Key Laboratory of Catalytic Materials and Reaction Engineering (RIPP, SINOPEC) under Project No. 33600000-15-ZC06070004the supports from the Fundamental Research Funds for Central Universities, the Xiamen University (No. 20720160079)the Collaborative Innovation Center of HighEnd Equipment Manufacturing in Fujian are also acknowledged
文摘In this study, the laminated porous metal fiber sintered felt(PMFSF) functioning as catalyst support was used in a cylindrical methanol steam reforming(MSR) microreactor for hydrogen production. The PMFSF was fabricated by the low temperature solid-phase sintering method using metal fibers such as copper fibers and aluminum fibers which are obtained by the multi-tooth cutting method. The two-layer impregnation method was employed to coat Cu/Zn/Al/Zr catalyst on the PMFSF. The effect of fiber material, uniform porosity and gradient porosity on the performance of methano steam reforming microreactor was studied by varying the gas hourly space velocity(GHSV) and reaction temperature. Our results showed that the loading strength of porous copper fiber sintered felt(PCFSF) was better than porous aluminum fiber sintered felt(PAFSF). Under the same reaction conditions, the PCFSF showed higher methanol conversion and more H_2 output than PAFSF. Moreover, the gradient porosity(Type 5: 90%×80%×70%) of PMFSF used as the catalyst support in microreactor demonstrated a best reaction performance for hydrogen production.
