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
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
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
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
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
Tonalid,an important fragrance ingredient with widespread applicatio n,was synthesized via two FriedelCrafts reactions,which were catalyzed by AlCl_(3).The traditional tonalid production was conducted in batch stirrin...Tonalid,an important fragrance ingredient with widespread applicatio n,was synthesized via two FriedelCrafts reactions,which were catalyzed by AlCl_(3).The traditional tonalid production was conducted in batch stirring tank reactors,suffering from low production capacity and the safety hazard of temperature runaway.To solve these problems,the continuous-flow technologies were developed for the highefficiency and intrinsically safe synthesis of tonalid in microreactors.Catalyst AlCl_(3)was neatly homogenized in proper solvents by forming complex with reactant,which was a necessary step for the continuous synthesis in microreactors.Several reaction conditions,including reactant molar ratio,catalyst concentration,temperature,and microchannel hydrodynamic diameter,were investigated for the two Friedel-Crafts reactions in micro reactors.At optimized conditions,the yields of the two Friedel-Crafts reactions were 44.15%and 97.55%,respectively.In comparison with the batch reactors,the reaction times of these two reactions could both be reduced by nearly two thirds in microreactors at the similar yield.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
High-purity ethylene carbonate(EC)is widely used as battery electrolyte,polycarbonate monomer,organic intermediate,and so on.An economical and sustainable route to synthesize high-purity ethylene carbonate(EC)via the ...High-purity ethylene carbonate(EC)is widely used as battery electrolyte,polycarbonate monomer,organic intermediate,and so on.An economical and sustainable route to synthesize high-purity ethylene carbonate(EC)via the transesterification of dimethyl carbonate(DMC)with ethylene glycol(EG)is provided in this work.However,this reaction is so fast that the reaction kinetics,which is essential for the industrial design,is hard to get by the traditional measuring method.In this work,an easy-to-assemble microreactor was used to precisely determine the reaction kinetics for the fast transesterification of DMC with EG using sodium methoxide as catalyst.The effects of flow rate,microreactor diameter,catalyst concentration,reaction temperature,and reactant molar ratio were investigated.An activity-based pseudohomogeneous kinetic model,which considered the non-ideal properties of reaction system,was established to describe the transesterification of DMC with EG.Detailed kinetics data were collected in the first 5 min.Using these data,the parameters of the kinetic model were correlated with the maximum average error of 11.19%.Using this kinetic model,the kinetic data at different catalyst concentrations and reactant molar ratios were predicted with the maximum average error of 13.68%,suggesting its satisfactory prediction performance.展开更多
The integration of microreactor and ultrasound represents an emerging area for process intensification and has attracted considerable attention in recent years.One of the most important meso-scientific issues in ultra...The integration of microreactor and ultrasound represents an emerging area for process intensification and has attracted considerable attention in recent years.One of the most important meso-scientific issues in ultrasound techniques is acoustic cavitation,which plays a vital role in the macroscopic performance of an ultrasonic microreactor.In this review,we first briefly summarize the latest research on acoustic cavitation phenomena in microreactors.The effects of channel configuration,solvent properties,and ultrasound parameters are systematically reviewed.In addition,the role of acoustic cavitation in various chemical processes(e.g.,mixing,absorption,emulsification,and particle synthesis)is presented from a mesoscale perspective,which in turn provides guidance for ultrasound applications.A thorough under-standing of the ultrasound intensification mechanism will contribute to the future development of this promising technology.展开更多
Based on microreactors, the representative Baylis-Hillman reaction of cyclopent-2-enone coupled with 4-nitrobenzaldehyde in the presence of imidazole could be accelerated by manipulating the temperature and electric f...Based on microreactors, the representative Baylis-Hillman reaction of cyclopent-2-enone coupled with 4-nitrobenzaldehyde in the presence of imidazole could be accelerated by manipulating the temperature and electric field. Furthermore, the electric field was used in promoting Baylis-Hillman reaction for the first time with the rate acceleration approximately 5.2-fold higher than that carried out in conventional vessels as well as 4.0-fold under control of temperature. Meanwhile, the products of Baylis-Hillman reaction at every time point could be collected and then determined by capillary micellar electrokinetic chromatography.展开更多
To address the energy challenges,scientists have designed various artificial light-harvesting systems inspired by photosynthesis.Notably,for light-harvesting systems,an energytransfer efficiency close to 100%with an a...To address the energy challenges,scientists have designed various artificial light-harvesting systems inspired by photosynthesis.Notably,for light-harvesting systems,an energytransfer efficiency close to 100%with an antenna effect greater than 10 is generally considered a good application criterion.[1]Today,building an efficient light-harvesting system at a low cost is still demanding.展开更多
Chemical synthesis is essential in industries such as petrochemicals, fine chemicals, and pharmaceuticals, driving economic and social development. The increasing demand for new molecules and materials calls for novel...Chemical synthesis is essential in industries such as petrochemicals, fine chemicals, and pharmaceuticals, driving economic and social development. The increasing demand for new molecules and materials calls for novel chemical reactions;however, manual experimental screening is time-consuming. Artificial intelligence (AI) offers a promising solution by leveraging large-scale experimental data to model chemical reactions, although challenges such as the lack of standardization and predictability in chemical synthesis hinder AI applications. Additionally, the multi-scale nature of chemical reactions, along with complex multiphase processes, further complicates the task. Recent advances in microchemical systems, particularly continuous flow methods using microreactors, provide precise control over reaction conditions, enhancing reproducibility and enabling high-throughput experimentation. These systems minimize transport-related inconsistencies and facilitate scalable industrial applications. This review systematically explores recent developments in intelligent synthesis based on microchemical systems, focusing on reaction system design, synthesis robots, closed-loop optimization, and high-throughput experimentation, while identifying key areas for future research.展开更多
Herein,the liquid-solid mass trans fer characteristics in micropacked bed reactors(μPBRs)operated with immiscible liquid-liquid two-phase flow is experimentally investigated.It is found that the overall volumetric li...Herein,the liquid-solid mass trans fer characteristics in micropacked bed reactors(μPBRs)operated with immiscible liquid-liquid two-phase flow is experimentally investigated.It is found that the overall volumetric liquid-solid mass transfer coefficient(k_(s)a)increases with the total flow rate and the channelto-particle diameter ratio,while decreases with the organic-to-aqueous phase flow rate ratio.A satisfactory correlation model for calculating k_(s)a of the liquid-liquid μPBRs is developed.The new knowledge obtained would be useful in guiding the design and optimization of the liquid-liquid μPBRs.展开更多
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
The Intergovernmental Panel on Climate Change(IPCC)recognises the pivotal role of renewable energies in the future energy system and the achievement of the zero-emission target.The implementation of renewables should ...The Intergovernmental Panel on Climate Change(IPCC)recognises the pivotal role of renewable energies in the future energy system and the achievement of the zero-emission target.The implementation of renewables should provide major opportunities and enable a more secure and decentralised energy supply system.Renewable fuels provide long-term solutions for the transport sector,particularly for applications where fuels with high energy density are required.In addition,it helps reducing the carbon footprint of these sectors in the long-term.Information on biomass characteristics feedstock is essential for scaling-up gasification from the laboratory to industrial-scale.This review deals with the transformation biogenic residues into a valuable bioenergy carrier like biomethanol as the liquid sunshine based on the combination of modified mature technologies such as gasification with other innovative solutions such as membranes and microchannel reactors.Tar abatement is a critical process in product gas upgrading since tars compromise downstream processes and equipment,for this,membrane technology for upgrading syngas quality is discussed in this paper.Microchannel reactor technology with the design of state-of-the-art multifunctional catalysts provides a path to develop decentralised biomethanol synthesis from biogenic residues.Finally,the development of a process chain for the production of(i)methanol as an intermediate energy carrier,(ii)electricity and(iii)heat for decentralised applications based on biomass feedstock flexible gasification,gas upgrading and methanol synthesis is analysed.展开更多
Micro reactors are the essential part of thermal analysis techniques for characterizing gas-solid thermochemical reactions. The dynamic and diversified needs for investigating various complex materials and gas-solid r...Micro reactors are the essential part of thermal analysis techniques for characterizing gas-solid thermochemical reactions. The dynamic and diversified needs for investigating various complex materials and gas-solid reactions have led to the development of a variety of different microreactors over the years. Solid particles in microreactors are normally heated by furnaces from outside, resistive elements from inside, direct contact with bed particles, or other non-resistively methods. Solid particles can be fixed or fluidized in reactors where gas-solid contacts vary from diffusion-dominated to nearly diffusion-free conditions. Based on these characteristics, in this article we presented a broad classification for microreactors used for thermal analysis of gas-solid reactions. For each of the most popularly used microreactors, their features and limitations are briefly reviewed. By addressing the diversity of the microreactors used in the field of thermal analysis, the review aims at providing general guidance for the selection and operation of the microreactor to satisfy one's practical specific needs.展开更多
Two beamlines and stations for soft X-ray lithography and hard X-ray lithography at NSRL are presented. Synchrotron radiation lithography (SRL) and mask techniques are developed, and the micro-electro-mechanical syste...Two beamlines and stations for soft X-ray lithography and hard X-ray lithography at NSRL are presented. Synchrotron radiation lithography (SRL) and mask techniques are developed, and the micro-electro-mechanical systems (MEMS) techniques are also investigated at NSRL. In this paper, some results based on SRL and MEMS techniques are reported, and sub-micron and high aspect ratio microstructures are given. Some micro-devices, such as microreactors are fabricated at NSRL.展开更多
Gas-liquid microreaction technology has shown great potential in a variety of industrial relevant mass transfer operations and reactions. This paper outlines the current research status of this technology with emphasi...Gas-liquid microreaction technology has shown great potential in a variety of industrial relevant mass transfer operations and reactions. This paper outlines the current research status of this technology with emphasis on reactor design, hydrodynamics and mass transfer phenomena as well as reaction applications. The future challenges of this important technology are also summarized.展开更多
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 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.
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.
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financial support for this work from the National Natural Science Foundation of China(No.21706034)the Natural Science Foundation of Fujian Province(No.2021J01645)the Key Program of Qingyuan Innovation Laboratory(No.00221004)。
文摘Tonalid,an important fragrance ingredient with widespread applicatio n,was synthesized via two FriedelCrafts reactions,which were catalyzed by AlCl_(3).The traditional tonalid production was conducted in batch stirring tank reactors,suffering from low production capacity and the safety hazard of temperature runaway.To solve these problems,the continuous-flow technologies were developed for the highefficiency and intrinsically safe synthesis of tonalid in microreactors.Catalyst AlCl_(3)was neatly homogenized in proper solvents by forming complex with reactant,which was a necessary step for the continuous synthesis in microreactors.Several reaction conditions,including reactant molar ratio,catalyst concentration,temperature,and microchannel hydrodynamic diameter,were investigated for the two Friedel-Crafts reactions in micro reactors.At optimized conditions,the yields of the two Friedel-Crafts reactions were 44.15%and 97.55%,respectively.In comparison with the batch reactors,the reaction times of these two reactions could both be reduced by nearly two thirds in microreactors at the similar yield.
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support for this work from the National Natural Science Foundation of China(21706034)the Natural Science Foundation of Fujian Province(2021J01645)the Key Program of Qingyuan Innovation Laboratory(00221004).
文摘High-purity ethylene carbonate(EC)is widely used as battery electrolyte,polycarbonate monomer,organic intermediate,and so on.An economical and sustainable route to synthesize high-purity ethylene carbonate(EC)via the transesterification of dimethyl carbonate(DMC)with ethylene glycol(EG)is provided in this work.However,this reaction is so fast that the reaction kinetics,which is essential for the industrial design,is hard to get by the traditional measuring method.In this work,an easy-to-assemble microreactor was used to precisely determine the reaction kinetics for the fast transesterification of DMC with EG using sodium methoxide as catalyst.The effects of flow rate,microreactor diameter,catalyst concentration,reaction temperature,and reactant molar ratio were investigated.An activity-based pseudohomogeneous kinetic model,which considered the non-ideal properties of reaction system,was established to describe the transesterification of DMC with EG.Detailed kinetics data were collected in the first 5 min.Using these data,the parameters of the kinetic model were correlated with the maximum average error of 11.19%.Using this kinetic model,the kinetic data at different catalyst concentrations and reactant molar ratios were predicted with the maximum average error of 13.68%,suggesting its satisfactory prediction performance.
基金This work was supported by the National Natural Science Foun-dation of China(No.91634204)the Youth Innovation Promotion Association CAS(No.2017229)Dalian Science&Technology Innovation Fund(No.2018J11CY019).
文摘The integration of microreactor and ultrasound represents an emerging area for process intensification and has attracted considerable attention in recent years.One of the most important meso-scientific issues in ultrasound techniques is acoustic cavitation,which plays a vital role in the macroscopic performance of an ultrasonic microreactor.In this review,we first briefly summarize the latest research on acoustic cavitation phenomena in microreactors.The effects of channel configuration,solvent properties,and ultrasound parameters are systematically reviewed.In addition,the role of acoustic cavitation in various chemical processes(e.g.,mixing,absorption,emulsification,and particle synthesis)is presented from a mesoscale perspective,which in turn provides guidance for ultrasound applications.A thorough under-standing of the ultrasound intensification mechanism will contribute to the future development of this promising technology.
基金Project supported by Ministry of Science and Technology of China （No. 2007CB714504）, the National Natural Science Foundation of China （Nos. 20875091, 20935005） and Chinese Academy of Sciences.
文摘Based on microreactors, the representative Baylis-Hillman reaction of cyclopent-2-enone coupled with 4-nitrobenzaldehyde in the presence of imidazole could be accelerated by manipulating the temperature and electric field. Furthermore, the electric field was used in promoting Baylis-Hillman reaction for the first time with the rate acceleration approximately 5.2-fold higher than that carried out in conventional vessels as well as 4.0-fold under control of temperature. Meanwhile, the products of Baylis-Hillman reaction at every time point could be collected and then determined by capillary micellar electrokinetic chromatography.
文摘To address the energy challenges,scientists have designed various artificial light-harvesting systems inspired by photosynthesis.Notably,for light-harvesting systems,an energytransfer efficiency close to 100%with an antenna effect greater than 10 is generally considered a good application criterion.[1]Today,building an efficient light-harvesting system at a low cost is still demanding.
基金supported by the National Natural Science Foundation of China(22378227)Shijiazhuang Science and Technology Bureau(231790163A).
文摘Chemical synthesis is essential in industries such as petrochemicals, fine chemicals, and pharmaceuticals, driving economic and social development. The increasing demand for new molecules and materials calls for novel chemical reactions;however, manual experimental screening is time-consuming. Artificial intelligence (AI) offers a promising solution by leveraging large-scale experimental data to model chemical reactions, although challenges such as the lack of standardization and predictability in chemical synthesis hinder AI applications. Additionally, the multi-scale nature of chemical reactions, along with complex multiphase processes, further complicates the task. Recent advances in microchemical systems, particularly continuous flow methods using microreactors, provide precise control over reaction conditions, enhancing reproducibility and enabling high-throughput experimentation. These systems minimize transport-related inconsistencies and facilitate scalable industrial applications. This review systematically explores recent developments in intelligent synthesis based on microchemical systems, focusing on reaction system design, synthesis robots, closed-loop optimization, and high-throughput experimentation, while identifying key areas for future research.
文摘Herein,the liquid-solid mass trans fer characteristics in micropacked bed reactors(μPBRs)operated with immiscible liquid-liquid two-phase flow is experimentally investigated.It is found that the overall volumetric liquid-solid mass transfer coefficient(k_(s)a)increases with the total flow rate and the channelto-particle diameter ratio,while decreases with the organic-to-aqueous phase flow rate ratio.A satisfactory correlation model for calculating k_(s)a of the liquid-liquid μPBRs is developed.The new knowledge obtained would be useful in guiding the design and optimization of the liquid-liquid μPBRs.
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support for this work has been obtained from the Junta de Andalucía projects with reference P20-00594 co-funded by the European Union FEDER。
文摘The Intergovernmental Panel on Climate Change(IPCC)recognises the pivotal role of renewable energies in the future energy system and the achievement of the zero-emission target.The implementation of renewables should provide major opportunities and enable a more secure and decentralised energy supply system.Renewable fuels provide long-term solutions for the transport sector,particularly for applications where fuels with high energy density are required.In addition,it helps reducing the carbon footprint of these sectors in the long-term.Information on biomass characteristics feedstock is essential for scaling-up gasification from the laboratory to industrial-scale.This review deals with the transformation biogenic residues into a valuable bioenergy carrier like biomethanol as the liquid sunshine based on the combination of modified mature technologies such as gasification with other innovative solutions such as membranes and microchannel reactors.Tar abatement is a critical process in product gas upgrading since tars compromise downstream processes and equipment,for this,membrane technology for upgrading syngas quality is discussed in this paper.Microchannel reactor technology with the design of state-of-the-art multifunctional catalysts provides a path to develop decentralised biomethanol synthesis from biogenic residues.Finally,the development of a process chain for the production of(i)methanol as an intermediate energy carrier,(ii)electricity and(iii)heat for decentralised applications based on biomass feedstock flexible gasification,gas upgrading and methanol synthesis is analysed.
基金supported by both the National Natural Science Foundation of China(U1903130 and U1908201)the Ministry of Science and Technology of the People's Republic of China(2020YFC1909300).
文摘Micro reactors are the essential part of thermal analysis techniques for characterizing gas-solid thermochemical reactions. The dynamic and diversified needs for investigating various complex materials and gas-solid reactions have led to the development of a variety of different microreactors over the years. Solid particles in microreactors are normally heated by furnaces from outside, resistive elements from inside, direct contact with bed particles, or other non-resistively methods. Solid particles can be fixed or fluidized in reactors where gas-solid contacts vary from diffusion-dominated to nearly diffusion-free conditions. Based on these characteristics, in this article we presented a broad classification for microreactors used for thermal analysis of gas-solid reactions. For each of the most popularly used microreactors, their features and limitations are briefly reviewed. By addressing the diversity of the microreactors used in the field of thermal analysis, the review aims at providing general guidance for the selection and operation of the microreactor to satisfy one's practical specific needs.
文摘Two beamlines and stations for soft X-ray lithography and hard X-ray lithography at NSRL are presented. Synchrotron radiation lithography (SRL) and mask techniques are developed, and the micro-electro-mechanical systems (MEMS) techniques are also investigated at NSRL. In this paper, some results based on SRL and MEMS techniques are reported, and sub-micron and high aspect ratio microstructures are given. Some micro-devices, such as microreactors are fabricated at NSRL.
基金Supported by the National Natural Science Foundation of China （20490208, 20676129）, the National High Technology Research and Development Program of China （2006AA05Z233, 2007AA030206）.
文摘Gas-liquid microreaction technology has shown great potential in a variety of industrial relevant mass transfer operations and reactions. This paper outlines the current research status of this technology with emphasis on reactor design, hydrodynamics and mass transfer phenomena as well as reaction applications. The future challenges of this important technology are also summarized.
