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        <title>Frontiers in Chemical Engineering | Microfluidic Engineering and Process Intensification section | New and Recent Articles</title>
        <link>https://www.frontiersin.org/journals/chemical-engineering/sections/microfluidic-engineering-and-process-intensification</link>
        <description>RSS Feed for Microfluidic Engineering and Process Intensification section in the Frontiers in Chemical Engineering journal | New and Recent Articles</description>
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        <pubDate>2026-05-13T11:11:00.168+00:00</pubDate>
        <ttl>60</ttl>
        <item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fceng.2024.1526472</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fceng.2024.1526472</link>
        <title><![CDATA[Editorial: Microfluidic-based technologies for sustainable process intensification]]></title>
        <pubdate>2024-12-04T00:00:00Z</pubdate>
        <category>Editorial</category>
        <author>Harrson S. Santana</author><author>Joaquin Ortega-Casanova</author><author>Babak Aghel</author><author>João Lameu Silva</author>
        <description></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fceng.2024.1451222</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fceng.2024.1451222</link>
        <title><![CDATA[Time scale analysis of enzymatic reduction of uric acid in a microfluidic biomedical device]]></title>
        <pubdate>2024-10-08T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Alireza Asgharpour Masouleh</author><author>Jaturavit Pantakitcharoenkul</author><author>Matthew Coblyn</author><author>Igor Plazl</author><author>Goran N. Jovanovic</author>
        <description><![CDATA[Time Scale Analysis (TSA) is an investigative tool used in engineering design to identify locations in processes that should be a focus of Process Intensification (PI). Furthermore, TSA points to process variables and parameters that could be used to advance and measure PI improvement. However, TSA cannot suggest any specific design solution to intensify process performance. Instead, design engineers should use their fundamental knowledge and creative intelligence to specify detailed design transformations. TSA will then provide a specific quantitative measure of the improvement. TSA implementation improves an explicitly defined process performance, thus helping achieve process intensification goals. TSA is based on first principles, and it utilizes Characteristic Times (CT) such as diffusion, mean residence, and reaction times to improve an existing process. In this study, we specifically consider microfluidic biomedical devices. To illustrate the genesis of CT and TSA, we start by developing a mathematical model of an enzymatic degradation process in a biomedical device called iCore based on mass, momentum, and kinetic equations. After introducing user-defined scaling parameters, we extract CTs pertinent to the enzymatic degradation of uric acid in this microfluidic biomedical device. Diffusion coefficients, microchannel architectural characteristics, enzyme loading, hydrogel thickness, and characteristic parameters of enzyme kinetics are the parameters and process variables incorporated in this analysis. Finally, we compared the extracted CTs with a COMSOL Multiphysics parametric study to demonstrate how time scale analysis as a design tool and adjusting design parameters, such as diffusion coefficient, hydrogel layer thickness, substrate concentration, and enzyme concentration, can enhance the enzymatic reaction process without a need for complex computational modeling. It is crucial to recognize that pertinent CTs can be determined by understanding the type and nature of the observed process, previous experience, published data, and other foundational engineering design work. There is no need for mathematical modeling and numerical simulations to identify and acknowledge the CTs relevant and essential to the observed process; in this work, we only illustrate the principal origin of CTs via a detailed mathematical model of the process, as previously reported by Jovanovic et al. Therefore, in a routine application of TSA, it is important to remember that mathematical modeling and detailed numerical simulations are not necessary. This is a very comforting fact when TSA is deployed as a tool in higher-level process design functions. The investigations on how best to apply TSA in these higher level design functions such as Process Intensification, scale-up/numbering-up, change of device architecture, change of operating conditions, change of process feed characteristics, change of material physical and chemical properties, parametric optimization of the system for various objective functions, and techno-economic analysis, are yet to be studied and reported.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fceng.2024.1445900</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fceng.2024.1445900</link>
        <title><![CDATA[Industry relevant microfluidic platforms for mineral leaching experiments]]></title>
        <pubdate>2024-09-09T00:00:00Z</pubdate>
        <category>Review</category>
        <author>Daisy Yang</author><author>Craig Priest</author>
        <description><![CDATA[Microfluidic and lab-on-a-chip devices offer exquisite temporal and spatial control over chemical and physical processes that are important in mineral exploration and mining. These include mineral-water interfacial reactions, dissolution, and adsorption/desorption in pores, fractures, or other micro/nanostructures. Microfluidic mineral studies offer advantages of small sample and reagent volumes, high throughout, and short analytical cycles that may enable in-field mining decisions. However, not many microfluidic studies have targeted these mining sector challenges for mineral leaching. In this review, special attention is given to microscale experimental platforms for predicting extraction and leaching of industrially-relevant samples (real ore samples). Advantages and challenges of these platforms are given. The review concludes that there are significant opportunities for microfluidics in mineral analysis, screening, process intensification, and process control in the resource and minerals sector.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fceng.2024.1443949</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fceng.2024.1443949</link>
        <title><![CDATA[Numerical modeling and experimental validation of fluid flow in micro- and meso-fluidic siphons]]></title>
        <pubdate>2024-08-12T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Nour Akhras</author><author>Gurjas Singh</author><author>Kirandeep K. Gill</author><author>Shaan Bola</author><author>Kareem Al-Hakeem</author><author>Nuno M. Reis</author>
        <description><![CDATA[Siphons have been used for thousands of years to transfer fluids without the use of pumps or power and are present in our daily lives. Paradoxically, it is only in recent decades that the operation of siphons has been fully clarified, which is now understood to be exclusively linked to gravity and molecular cohesion. Siphons are uniquely able to offer automatic, intermittent flow, yet present the main drawback of requiring a source of energy to induce initial flow. Our research team has recently disclosed a microfluidic siphon able to self-prime and deliver a sequence of bioanalytical reagents, previously demonstrated for high-performance, multi-reagents diagnostic testing. Here we show for the first time 2D and 3D computational fluid dynamics (CFD) modeling and the experimental characterization of fluid flow in a range of miniaturized hydrophilic siphons of varying hydraulic liquid height-to-length ratios, ΔH/LT = 0–0.9, using fluids of varying viscosities. CFD simulations using velocity- and pressure-driven inlet boundary conditions were generally in good agreement with experimental fluid flow rates and pressure-balance predictions for plastic ∼0.2 mm and glass ∼0.6 mm internal diameter microfluidic siphons. CFD predictions of fluid flow in “meso-scale” siphons with 1 and 2 mm internal diameters also fully matched normalized experimental data, suggesting that miniaturized siphons are scalable. Their discharge rate and pressure drop are readily predicted and fine-tunable through the physical properties of the fluid and some design parameters of the siphon. The wide range of experimental and numerical parameters studied here provide an important framework for the design and application of gravity-driven micro- and meso-fluidic siphons in many applications, including but not limited to life sciences, clinical diagnostics, and process intensification.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fceng.2024.1440657</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fceng.2024.1440657</link>
        <title><![CDATA[Numerical evaluation of methanol synthesis in catalytic wall-coated microreactors: scale-up and performance analysis of planar and monolithic designs]]></title>
        <pubdate>2024-08-02T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>João Lameu da Silva</author><author>Harrson Silva Santana</author><author>Maximilian Joachim Hodapp</author>
        <description><![CDATA[Methanol is one of the most important primary chemical compounds, being an interesting alternative for portable energy applications and also acting as a molecular platform for the synthesis of a wide range of commodities and high-added-value products. Traditionally, methanol is obtained by catalytic hydrogenation using synthesis gas (CO/CO2/H2) in fixed-bed reactors (FBRs), which require large reaction volumes and are limited by heat and mass transfer. Wall-coated microreactor technology (MRT) offers a promising alternative to traditional fixed-bed reactors. Despite their potential, industrial-scale adoption of microreactors faces challenges related to scale-up. This article aimed to assess methanol synthesis in wall-coated microreactors (planar, or MRP, and monolithic, or MRM) through numerical performance evaluation, using a fixed-bed reactor as a reference. A pre-analysis of carbon conversion into methanol from experimental data provided insightful conclusions about recommended operating parameters, suggested as 50 bar, 250°C, a CO2 ratio of 0.3–0.4, a gas hourly space velocity (GHSV) of 6,000–8,000 mL/g.h, and a stoichiometric hydrogen/carbon ratio of 2–4. The numerical model, coupling chemical kinetics into fluid dynamics, demonstrated good agreement with experimental data. Subsequently, a design of experiments identified optimal operating conditions for methanol synthesis (250°C, 50 bar, CO2 ratio = 0.32, GHSV = 7,595 mL/g.h, hydrogen/carbon ratio = 2.4) in an FBR. The MRP and MRM presented equivalent performance with the FBR after adjusting the surface catalytic loading. In particular, the MRP showed a potential feature for scale-up due to the decreased pressure drop. A reactor block with 10 parallelized channels was designed and evaluated by changing GHSV between 5,000 and 50,000 mL/g.h and varying surface catalytic loading from 0.04 to 0.12 kg/m2. Despite the formation of recirculation zones in the conical region, the flow distribution remained satisfactory, ensuring virtually uniform methanol production among units, providing increased operational flow, and maintaining the microscale efficiency with a relatively low pressure drop. The present article provides a comprehensive analysis of the fundamental interplay between kinetic effects, mass transfer phenomena, and reactor design in methanol synthesis by applying MRT concepts, offering important insights for performance optimization and scale-up of wall-coated microreactors.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fceng.2024.1434131</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fceng.2024.1434131</link>
        <title><![CDATA[Cu-alginate hydrogels in microfluidic systems: a sustainable catalytic approach for click chemistry]]></title>
        <pubdate>2024-07-16T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Arijana Ramšak</author><author>Martin Gazvoda</author><author>Igor Plazl</author><author>Rok Ambrožič</author>
        <description><![CDATA[This work explores the innovative use of copper-alginate (Cu-alginate) hydrogels within microfluidic systems to catalyze dipolar cycloaddition reactions, emphasizing green chemistry principles and process intensification. Utilizing naturally occurring biopolymers, such as alginates, provides an environmentally friendly alternative to conventional catalyst supports due to their biocompatibility, biodegradability, and effective metal ion immobilization capabilities. The integration of these biopolymer-based catalysts into microfluidic devices allows for precise control over reaction conditions, leading to enhanced reaction kinetics and mass transfer efficiencies. Our results demonstrate that Cu-alginate hydrogels effectively catalyze the formation of 1,4-disubstituted 1,2,3-triazoles through [3 + 2] dipolar cycloaddition reactions with high regioselectivity and conversion. The microfluidic setup ensures rapid and efficient synthesis, surpassing traditional batch reaction methods in both reaction rate and environmental impact by reducing solvent usage and waste generation. Furthermore, the use of microfluidics contributes to the reproducibility and scalability of the synthesis process, important for industrial applications. The model-based design and its simulations have been employed to further understand and optimize the reaction system. Diffusion through the gel layer and catalytic reaction kinetics estimated from experimental data were included in the model, providing a theoretical foundation for a comprehensive process evaluation. This study not only advances the field of sustainable catalysis by demonstrating the practical utility of biopolymer-supported catalysts in microfluidic systems, but also sets the stage for further research into biopolymer applications in complex chemical syntheses.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fceng.2024.1375071</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fceng.2024.1375071</link>
        <title><![CDATA[The integrated microfluidic photocatalytic planar reactor under continuous operation]]></title>
        <pubdate>2024-04-17T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Xue-hui Ge</author><author>Nanjie Wei</author><author>Xinyue Hu</author><author>Qinyin Xie</author><author>Xiaoda Wang</author><author>Ling Li</author><author>Ting Qiu</author>
        <description><![CDATA[An integrated microfluidic planar reactor is essential for achieving efficient and enhanced photocatalytic water treatment. Optimization of catalysts is an area of intense study owing to the need to enhance the performances of microreactors. A high-efficiency photocatalytic microreactor is presented here by combining a planar microreactor with a high-efficiency photocatalyst. TiO2 nanoparticles doped with Y and Yb were prepared to improve the photocatalytic reaction efficiency. First, better performance is achieved with the Y, Yb/TiO2 and TiO2 microreactors than conventional bulk reactors because of good photodegradation and a high reaction rate. Then, the Y, Yb/TiO2 film microreactor exhibits not only efficient catalytic activity with UV light but also higher photocatalytic activity under visible light irradiation than that achieved by a TiO2 film microreactor. The reaction rate constant of the Y, Yb/TiO2 film microreactor is approximately 0.530 s–1, which is twice that of the TiO2 film microreactor. Moreover, the performances under continuous and intermittent reactions are compared to evaluate the stability of the microreactor, thereby building the foundation for practical application of continuous water treatment in the microreactor.The planar microreactor provides a convenient platform for studying photodegradation under various conditions, such as different temperatures, flow rates, light irradiation (UV and Vis), and reaction modes (continuous and intermittent).]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fceng.2023.1144009</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fceng.2023.1144009</link>
        <title><![CDATA[Intensified biodiesel production from waste cooking oil and flow pattern evolution in small-scale reactors]]></title>
        <pubdate>2023-04-21T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Dimitrios Tsaoulidis</author><author>Eduardo Garciadiego-Ortega</author><author>Panagiota Angeli</author>
        <description><![CDATA[In this paper, the transesterification reaction of waste cooking oil (WCO) with methanol using KOH as catalyst to produce biodiesel was performed in a micro-reactor (1 mm ID) using a cross-flow inlet configuration. The effects of different variables such as, methanol-to-oil molar ratio, temperature, catalyst concentration, and residence time on biodiesel yield, as well as the associated flow patterns during the transesterification reaction were investigated and the relationship between flow characteristics and mass transfer performance of the system was examined. The work reveals important aspects and the links between the hydrodynamic behaviour and the mass transfer performance of the intensified reactors. It was found that high yield (>90%) of biodiesel can be achieved in one-stage reaction using cross-flow micro-reactors for a wide range of conditions, i.e., methanol-to-oil molar ratio: 8–14, catalyst concentration: 1.4%–1.8% w/w, temperature: 55°C–60°C, and residence times: 55–75 s.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fceng.2022.838336</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fceng.2022.838336</link>
        <title><![CDATA[Shape design of channels and manifolds in a multichannel microreactor using thermal-fluid compartment models]]></title>
        <pubdate>2022-11-03T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Osamu Tonomura</author><author>Masaru Noda</author><author>Shinji Hasebe</author>
        <description><![CDATA[In the design of microreactors, the shape as well as the size is an important design factor for achieving high performance. Recent advances in computational fluid dynamics (CFD) enable us to know flow and temperature distributions in microreactors of various shapes and sizes without conducting experiments. However, it is often important to develop a simpler model than CFD to further reduce the computational time required for reactor design with iterative performance evaluations. In this research, a thermal-fluid compartment model-based approach is proposed for basic design of a multichannel microreactor. The proposed approach consists of two parts, i.e., thermal design and fluid design. In the thermal design part, two types of thermal compartments, which are used to discretize a reaction channel surrounded by wall and describe the mass and heat balances over the channel, are developed to optimize the channel shape. In the fluid design part, three types of fluid compartments, which are used to discretize the reactor and describe the mass and pressure balances over the reactor, are introduced to optimize manifold shape. The proposed approach is applied to a design problem and the results show that microchannels and manifolds with varying width are effective in realizing the uniform temperature and flow distributions, respectively. In addition to the proposed design approach, a transfer function-based compartment model is developed to estimate the residence time distribution of fluid in a microreactor without running time-dependent CFD simulation.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fceng.2022.1038183</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fceng.2022.1038183</link>
        <title><![CDATA[Editorial: Fundamentals, design and applications in process-intensifying equipment]]></title>
        <pubdate>2022-10-12T00:00:00Z</pubdate>
        <category>Editorial</category>
        <author>Adam Harvey</author><author>Martine Poux</author><author>Joelle Aubin</author>
        <description></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fceng.2022.966451</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fceng.2022.966451</link>
        <title><![CDATA[Process intensification in continuous flow organic synthesis with enabling and hybrid technologies]]></title>
        <pubdate>2022-09-07T00:00:00Z</pubdate>
        <category>Review</category>
        <author>Giorgio Grillo</author><author>Pedro Cintas</author><author>Mariachiara Colia</author><author>Emanuela Calcio Gaudino</author><author>Giancarlo Cravotto</author>
        <description><![CDATA[Industrial organic synthesis is time and energy consuming, and generates substantial waste. Traditional conductive heating and mixing in batch reactors is no longer competitive with continuous-flow synthetic methods and enabling technologies that can strongly promote reaction kinetics. These advances lead to faster and simplified downstream processes with easier workup, purification and process scale-up. In the current Industry 4.0 revolution, new advances that are based on cyber-physical systems and artificial intelligence will be able to optimize and invigorate synthetic processes by connecting cascade reactors with continuous in-line monitoring and even predict solutions in case of unforeseen events. Alternative energy sources, such as dielectric and ohmic heating, ultrasound, hydrodynamic cavitation, reactive extruders and plasma have revolutionized standard procedures. So-called hybrid or hyphenated techniques, where the combination of two different energy sources often generates synergistic effects, are also worthy of mention. Herein, we report our consolidated experience of all of these alternative techniques.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fceng.2022.896329</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fceng.2022.896329</link>
        <title><![CDATA[Continuous crystallisation of organic salt polymorphs]]></title>
        <pubdate>2022-08-10T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>John McGinty</author><author>Vaclav Svoboda</author><author>Pol MacFhionnghaile</author><author>Helen Wheatcroft</author><author>Chris J. Price</author><author>Jan Sefcik</author>
        <description><![CDATA[Organic salt crystallisation is of great importance to the pharmaceutical industry as many pharmaceutical products are marketed as salts with salt formation being an essential step in drug development. The model compound used in this work is the polymorphic organic salt ethylenediammonium 3,5-dinitrobenzoate (EDNB) which is the 2:1 salt of 3,5-dinitrobenzoic acid with ethylenediamine. Crystallisation of the two EDNB polymorphs, the stable monoclinic form and the metastable triclinic form, was performed in both semi-batch and continuous processes using continuous mixing approaches. It was demonstrated that continuous mixing approaches, using various types of continuous mixers (co-axial, Ehrfeld, X-mixer) can be used to crystallise the EDNB salt with consistent yield and particle size distribution while achieving control over polymorphic form. The experiments were designed with use of a solution speciation model which provided process understanding and insight to guide development of salt crystallisation processes.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fceng.2022.964767</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fceng.2022.964767</link>
        <title><![CDATA[Flash functional group-tolerant biaryl-synthesis based on integration of lithiation, zincation and negishi coupling in flow]]></title>
        <pubdate>2022-07-22T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Yosuke Ashikari</author><author>Kaiteng Guan</author><author>Aiichiro Nagaki</author>
        <description><![CDATA[We achieved an integration of a lithiation of aryl bromides, a zincation of thus-generated aryllithiums, and a Negishi coupling of the arylzinc with an aryl halide in one flow. Taking advantages of flow microreactors, biaryls bearing a wide range of functional groups, especially biaryls bearing multiple electrophilic-functionalities were synthesized.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fceng.2022.877498</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fceng.2022.877498</link>
        <title><![CDATA[Development of an Efficient, High Purity Continuous Flow Synthesis of Diazepam]]></title>
        <pubdate>2022-06-27T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Robert J. Nicholas</author><author>Michael A. McGuire</author><author>Seok-Hee Hyun</author><author>Madeline N. Cullison</author><author>David H. Thompson</author>
        <description><![CDATA[In an effort to strengthen the resiliency of supply chains for active pharmaceutical ingredients (API), continuous manufacturing processes may be optimized with respect to improved chemoselectivity, production rate, yield, and/or process intensity. We report an efficient two-step continuous flow synthesis of diazepam, an agent on the World Health Organization’s (WHO) list of essential medicines. Different conditions were rapidly screened in microfluidic chip reactors by varying residence times, temperatures, solvents, and ammonia sources to identify the best telescoped reaction conditions. We report a telescoped flow synthesis that uses two microreactors in series set to 0°C and 60°C, respectively, to produce a 96% yield of 91% pure diazepam within 15 min using an NH4Br/NH4OH solution in the second step. Diazepam of >98% purity was obtained after a single recrystallization.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fceng.2022.874019</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fceng.2022.874019</link>
        <title><![CDATA[A Novel Approach for Visualizing Mixing Phenomena of Reactive Liquid-Liquid Flows in Milli- and Micro-Channels]]></title>
        <pubdate>2022-06-06T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Torben Frey</author><author>Felix Kexel</author><author>Kayla Reata Dittmer</author><author>Sven Bohne</author><author>Marko Hoffmann</author><author>Hoc Khiem Trieu</author><author>Michael Schlüter</author>
        <description><![CDATA[Modular milli- and micro-structured systems represent a promising approach to exploit the potential of micro-process technology, including precise reaction control and scale-up. A major drawback of micro-structured devices is fouling and mixing mechanisms need to be investigated phenomenologically to better understand the processes that lead to fouling. Previous work was conducted to resolve 3D concentration fields by means of Laser-Induced Fluorescence (LIF) using a Confocal Laser Scanning Microscope (CLSM) (Frey et al., J Flow Chem, 2021, 11, 599–609). While the CLSM-LIF method yields detailed insight into concentration fields down to a few micrometers, it is limited to stationary flow structures only. Aubin et al. (Chemical Engineering Science, 2010, 65, 2065–2093) give a comprehensive review of methods to analyze mixing behavior. Most recent optical measurement methods rely on the detection of a single compound in mixtures. In case of reactive mixing, Tthe state of the art procedures to locally visualize micro mixing relies on tracking a reaction product which forms on molecular scale. In literature, only small micro-structures are manufactured from transparent materials, however larger milli-structures often lack optical accesses with sufficient quality. Selective laser-induced etching (SLE) is a new technique which enables the fabrication of larger milli-structures in transparent materials that are relevant for industry-scale applications. This work develops a method based on a concept of Kexel et al. (Chemie Ingenieur Technik, 2021, 93, 830–837) visualizing the selectivity of a competitive-consecutive gas-liquid reaction in a Taylor bubble flow. The main goal of this work is the analysis of the absorbance spectra of bromothymol blue (BTB) at different pH values in a miscible liquid-liquid system in a fused silica split-and-recombine mixer. The milli-structure of the mixer is manufactured by means of SLE. Backlight at different wavelengths is pulsed matching the recording frequency. In contrast to conventional UV/Vis setups, the absorbance is recorded locally within the mixer. The proposed method yields the 2D concentration distribution of multiple species with high spatial resolution. The spatially resolved reactant and product distribution unveils micro mixing and can yield important information about local root causes of fouling.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fceng.2022.779611</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fceng.2022.779611</link>
        <title><![CDATA[Capillary Microreactor for Initial Screening of Three Amine-Based Solvents for CO2 Absorption, Desorption, and Foaming]]></title>
        <pubdate>2022-06-01T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Anchu Ashok</author><author>Jaafar Ballout</author><author>Abdelbaki Benamor</author><author>Ma’moun Al-Rawashdeh</author>
        <description><![CDATA[Microreactor is a very attractive laboratory device for screening conditions and solvents in an efficient, safe and fast manner. Most reported work on microreactors for CO2 capturing deals with absorption and mass transfer performance with a limited number of studies on solvent regeneration. For the first time, foaming, which is a major operational challenge of CO2 capturing is being studied in combination with absorption and desorption in a capillary microreactor setup. To demonstrate the setup capabilities, three known amine-based solvents (MEA, MDEA, and AMP) were selected for the screening and evaluation studies. MEA had the highest CO2 absorption efficiency while MDEA had the lowest one. CO2 absorption efficiency increased with temperature, liquid flow rate, and amine concentration as per the literature. During the absorption work, the Taylor flow regime was maintained at the reactor inlet. CO2 desorption of loaded amine solutions was investigated at different concentrations and temperatures up to 85°C. MDEA solution had the highest desorption efficiency, followed by AMP and the least desorption efficiency was that of MEA. Foaming experimental results showed that MEA had a larger foaming region compared to AMP. However, more foaming happened with AMP at higher gas and liquid flow rates. A plug flow mathematical reactor model was developed to simulate the MEA-CO2 system. The model captured well the performance and trends of the studied system, however the absolute prediction deviated due to uncertainties in the used physical properties and mass transfer correlation. Selecting a solvent for chemical absorption depends on many more factors than these three studied parameters. Still, microreactor proves a valuable tool to generate experimental results under different conditions, with the least amount of consumables (less than 1 L solvents were used), in a fast manner, combined with a knowledge insight because of the uniqueness of the Taylor flow regime.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fceng.2022.862766</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fceng.2022.862766</link>
        <title><![CDATA[Flash Synthesis and Continuous Production of C-Arylglycosides in a Flow Electrochemical Reactor]]></title>
        <pubdate>2022-04-12T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Masahiro Takumi</author><author>Aiichiro Nagaki</author>
        <description><![CDATA[Electrochemistry provides a green and atom-efficient route to synthesize pharmaceutical and useful functional molecules, as it eliminates the need for the harsh chemical oxidants and reductants commonly used in traditional chemical reactions. To promote the implementation of electrochemical processes in the industry, there is a strong demand for the development of technologies that would allow for scale-up and a shortened reaction process time. Herein, we report that electrolysis was successfully accomplished using a flow-divided-electrochemical reactor within a few seconds, enabling the desired chemical conversion in a short period of time. Moreover, the narrow electrode gap of the flow reactor, which offers greener conditions than the conventional batch reactor, resulted in the continuous flash synthesis of C-arylglycosides.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fceng.2021.819752</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fceng.2021.819752</link>
        <title><![CDATA[Investigation of Parameter Control for Electrocatalytic Semihydrogenation in a Proton-Exchange Membrane Reactor Utilizing Bayesian Optimization]]></title>
        <pubdate>2022-01-26T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Yosuke Ashikari</author><author>Takashi Tamaki</author><author>Yusuke Takahashi</author><author>Yiyue Yao</author><author>Mahito Atobe</author><author>Aiichiro Nagaki</author>
        <description><![CDATA[Owing to its applicability in sustainable engineering, flow electrochemical synthesis in a proton-exchange membrane (PEM) reactor has attracted considerable attention. Because the reactions in PEM reactors are performed under electro-organic and flow-synthetic conditions, a higher number of reaction parameters exist compared to ordinary reactions. Thus, the optimization of such reactions requires significant amounts of energy, time, chemical and human resources. Herein, we show that the optimization of alkyne semihydrogenation in PEM reactors can be facilitated by means of Bayesian optimization, an applied mathematics strategy. Applying the optimized conditions, we also demonstrate the generation of a deuterated Z-alkene.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fceng.2021.788241</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fceng.2021.788241</link>
        <title><![CDATA[Gas–Liquid Slug Flow Studies in Microreactors: Effect of Nanoparticle Addition on Flow Pattern and Pressure Drop]]></title>
        <pubdate>2022-01-17T00:00:00Z</pubdate>
        <category>Original Research</category>
        <author>Jie Zong</author><author>Jun Yue</author>
        <description><![CDATA[Colloidal suspensions of nanoparticles (e.g., metals and oxides) have been considered as a promising working fluid in microreactors for achieving significant process intensification. Existing examples include their uses in microflow as catalysts for enhancing the reaction efficiency, or as additives to mix with the base fluid (i.e., to form the so-called nanofluids) for heat/mass transfer intensification. Thus, hydrodynamic characterization of such suspension flow in microreactors is of high importance for a rational design and operation of the system. In this work, experiments have been conducted to investigate the flow pattern and pressure drop characteristics under slug flow between N2 gas and colloidal suspensions in the presence of TiO2 or Al2O3 nanoparticles through polytetrafluoroethylene (PTFE) capillary microreactors. The base fluid consisted of water or its mixture with ethylene glycol. The slug flow pattern with nanoparticle addition was characterized by the presence of a lubricating liquid film around N2 bubbles, in contrast to the absence of liquid film in the case of N2-water slug flow. This shows that the addition of nanoparticles has changed the wall wetting property to be more hydrophilic. Furthermore, the measured pressure drop under N2-nanoparticle suspension slug flow is well described by the model of Kreutzer et al. (AIChE J 51(9):2428–2440, 2005) at the mixture Reynolds numbers ca. above 100 and is better predicted by the model of Warnier et al. (Microfluidics and Nanofluidics 8(1):33–45, 2010) at lower Reynolds numbers given a better consideration of the effect of film thickness and bubble velocity under such conditions in the latter model. Therefore, the employed nanoparticle suspension can be considered as a stable and pseudo single phase with proper fluid properties (e.g., viscosity and density) when it comes to the pressure drop estimation.]]></description>
      </item><item>
        <guid isPermaLink="true">https://www.frontiersin.org/articles/10.3389/fceng.2021.788653</guid>
        <link>https://www.frontiersin.org/articles/10.3389/fceng.2021.788653</link>
        <title><![CDATA[Modeling and Simulation of Reaction Environment in Photoredox Catalysis: A Critical Review]]></title>
        <pubdate>2022-01-14T00:00:00Z</pubdate>
        <category>Review</category>
        <author>Gabriela Xavier de Oliveira</author><author>Jéssica Oliveira de Brito Lira</author><author>Humberto Gracher Riella</author><author>Cíntia Soares</author><author>Natan Padoin</author>
        <description><![CDATA[From the pharmaceutical industry’s point of view, photoredox catalysis has emerged as a powerful tool in the field of the synthesis of added-value compounds. With this method, it is possible to excite the catalyst by the action of light, allowing electron transfer processes to occur and, consequently, oxidation and reduction reactions. Thus, in association with photoredox catalysis, microreactor technology and continuous flow chemistry also play an important role in the development of organic synthesis processes, as this technology offers high yields, high selectivity and reduced side reactions. However, there is a lack of a more detailed understanding of the photoredox catalysis process, and computational tools based on computational fluid dynamics (CFD) can be used to deal with this and boost to reach higher levels of accuracy to continue innovating in this area. In this review, a comprehensive overview of the fundamentals of photoredox catalysis is provided, including the application of this technology for the synthesis of added-value chemicals in microreactors. Moreover, the advantages of the continuous flow system in comparison with batch systems are pointed out. It was also demonstrated how modeling and simulation using computational fluid dynamics (CFD) can be critical for the design and optimization of microreactors applied to photoredox catalysis, so as to better understand the reagent interactions and the influence of light in the reaction medium. Finally, a discussion about the future prospects of photoredox reactions considering the complexity of the process is presented.]]></description>
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