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The use of metal-organic frameworks (MOFs) as CO2-gas-capture materials has attracted extensive research attention. In this study, two types of MOFs—Zn-MOF and ZnCe-MOF—were synthesized utilizing the microchannel reaction method, with water being employed as the solvent. The specific surface area, pore size, and pore volume of Zn-MOF and ZnCe-MOF were 1566.4 and 15.6 m2·g−1, 0.65 and 7.32 nm, as well as 1.65 and 0.03 cm3·g−1, respectively. Furthermore, Ce doping not only increased the pore size of ZnCe-MOF but also its adsorption energy from −0.19 eV (Zn-MOF) to −0.53 eV (ZnCe-MOF). At 298 K, the adsorption capacities of Zn-MOF and ZnCe-MOF were 0.66 and 0.74 mmol·g−1, respectively. In addition, the CO2 adsorption behaviors of Zn-MOF and ZnCe-MOF were linear and logarithmic, respectively. Theoretical calculations show that the results of adsorption thermodynamic simulations were consistent with the experiments. Thus, the preparation of ZnCe-MOF materials using a microchannel reactor provides a new approach for the continuous preparation of MOFs. [ABSTRACT FROM AUTHOR]

Microreactors have the advantages of high heat and mass transfer efficiency, strict control of reaction parameters, easy amplification, and good safety performance, and have been widely used in various fields such as chip manufacturing, fine chemicals, and biomanufacturing. However, narrow microchannels in microreactors often become filled with catalyst particles, leading to blockages. To address this challenge, this study proposes a multiphase flow heat transfer model based on the lattice Boltzmann method (LBM) to investigate the dynamic changes during the bubble collapse process and temperature distribution regularities. Based on the developed three-phase flow dynamics model, this study delves into the shock dynamic evolution process of bubble collapse and analyzes the temperature distribution regularities. Then, the flow patterns under different particle density conditions are explored. The study found that under the action of shock wave, the stable structure of the liquid film of the bubble is destroyed, and the bubble deforms and collapses. At the moment of bubble collapse, energy is rapidly transferred from the potential energy of the bubble to the kinetic energy of the flow field. Subsequently, the kinetic energy is converted into pressure waves. This results in the rapid generation of extremely high pressure in the flow field, creating high-velocity jets and intense turbulent vortices, which can enhance the mass transfer effects of the multiphase flows. At the moment of bubble collapse, a certain high temperature phenomenon will be formed at the collapse, and the high temperature phenomenon in this region is relatively chaotic and random. The pressure waves generated during bubble collapse have a significant impact on the motion trajectories of particles, while the influence on high-density particles is relatively small. The results offer a theoretical basis for understanding mass transfer mechanisms and particle flow patterns in three-phase flow. Moreover, these findings have significant practical implications for advancing technologies in industrial applications, including chip manufacturing and chemical process transport. [ABSTRACT FROM AUTHOR]

The study of microchannel methanol steam reforming plays an important role in improving the efficiency of hydrogen production and promoting the development of clean energy. This thesis numerically simulates a circle-triangle microchannel—a reactor catalyst with a porous media structure—that works with internal methanol combustion for heat supply and external methanol-reforming for hydrogen production. The heat transfer performance inside the microchannel and the chemical reaction kinetic rate of methanol were analyzed; the effects of different conditions such as inlet velocity, water-to-alcohol ratio, and reaction temperature on the hydrogen production performance of the microchannel reactor were analyzed, and the reaction law and transport characteristics inside this microchannel were revealed. The results show that the overall temperature distribution of the microchannel reactor is relatively uniform; the reforming reaction mainly occurs at the outer side of the porous catalytic layer, the internal mass transfer resistance is large, and the reforming reaction needs to optimize the pore structure of the catalytic layer to reduce the mass transfer limitation; the velocity variation in the reforming channel is large, the hydrogen yield increases with the temperature increase, and the water-alcohol ratio and inlet velocity need to be controlled to achieve the best performance. Practical Applications: This study focuses on the performance analysis of a microchannel methanol steam reforming reactor aimed at improving hydrogen production efficiency and promoting clean energy. Numerical simulations of the circular-triangular microchannel reactor revealed its heat transfer performance and chemical reaction kinetics. The temperature distribution of the reactor was relatively uniform, and the reforming reaction mainly occurred outside the catalyst layer. At the same time, the internal mass transfer resistance was significant, suggesting that the pore structure of the catalytic layer needed to be improved to enhance the catalyst utilization. Meanwhile, the flow rate in the reforming channel varied greatly, and the study showed that the inlet velocity and reaction time interacted with each other. Although the fast inlet velocity can improve the mass transfer efficiency, the length of the flow channel needs to be reasonably designed to ensure that the substance reacts adequately. This study provides a theoretical basis for the optimization of microchannel reactors and lays the foundation for the practical application of methanol steam reforming in hydrogen fuel cell vehicles, demonstrating the great potential for promoting clean energy and renewable resources. [ABSTRACT FROM AUTHOR]

As an important sustainable method for chemical synthesis, organic electrosynthesis experienced a renaissance in recent years for its excellent atom economy. Although microchannel reactors have been proposed to advanced electrosynthesis devices to obtain low energy cost and high reaction performance, the complex multiphasic flow in the electrochemical microchannels are very less reported and the effects of flow condition on the electrosynthesis reaction are less reported. Taking the electrosynthesis of tetraethyl thiuram disulfide (TETD) as a typical case, we developed a visualized electrochemical microchannel reactor equipped with fluorine‐doped tin oxide (FTO) loaded glass electrode to investigate the gas‐liquid‐liquid triple phase flow pattern and the main factors influenced the response current at certain applied cell voltage. The gas‐liquid‐liquid hybrid flow with low gas hold‐up and high liquid flow rate was found crucial for preventing coverage of TETD on the electrode, which provided 23.1 % low current attenuation ratio at 3.0 V cell voltage. The research not only exhibited the complex evolution mechanism of the response current, but also showed the importance of flow condition control for balancing the work efficiency and energy consumption of electrosynthesis process. [ABSTRACT FROM AUTHOR]

Microreactors are essential for microchemical reactions owing to their high mass transfer efficiency, precise control of reaction time, easy amplification, and good safety performance. These characteristics provide several advantages, including shortened reaction times and enhanced chemical reaction conversion rates, rendering microreactors particularly significant in chemical production. In this study, a finite-rate model was developed for the esterification of monobutyl chlorophosphate (MCP) and n-butanol in a microchannel reactor. This study investigates the impact of the microchannel's length-to-diameter ratio, the mass ratio of n-butanol to MCP at the inlet, and the inlet flow ratio on the entire reaction system through numerical simulations. The findings indicate that increasing the length-to-diameter ratio and reducing the inlet flow rate effectively prolongs the residence time of materials in the microreactor, thereby enhancing the conversion rate of the reactants. Optimal results are achieved with a moderate n-butanol/MCP mass ratio, which facilitates MCP transformation. Moreover, this study employs response surface analysis to investigate the influence of independent factors, such as the microchannel's length-to-diameter ratio, component ratio, and inlet velocity ratio, on MCP conversion rates. A prediction formula with conversion rate as the dependent variable and microchannel length-to-diameter ratio, component ratio, and inlet velocity ratio as independent variables was established. [ABSTRACT FROM AUTHOR]

Catalytic wet air oxidation (CWAO) process is employed for the treatment of N-tert-butyl-2-benzothiazolesulfenamide (TBBS) wastewater in a microchannel reactor that enables continuous operation of the reaction and allows for thorough mixing of oxygen and pollutants. To achieve the optimal process performance, four key parameters of pressure, temperature, time, and the mass ratio of input oxygen to wastewater COD are optimized using both response surface methodology (RSM) and backpropagation artificial neural network (BP-ANN). According to the correlation coefficients of model results and experimental data, BP-ANN performs better than RSM in simulation and prediction. The analysis of variance in RSM shows that all parameters are significant for the obtained quadratic model, but their interactions with each other are not significant. Connection weights algorithm is used to determine the relative importance of these parameters for the process efficiency, and it is demonstrated that temperature is the most influential parameter with a relative importance of 35.61%, followed by pressure (29.74%), time (19.53%) and ROC (15.12%). [ABSTRACT FROM AUTHOR]

[Introduction] CO2 catalytic hydrogenation for fuel synthesis is an economically feasible and large-scale implementable technology for CO2 utilization, which can solve the problems of environment and resource shortage, and has gained wide attention in recent years. In this work, a microchannel reactor for CO2 catalytic hydrogenation to synthesize hydrocarbon fuels is developed. [Method] Based on the design concept of thermodynamic calculation, catalyst preparation, reactor design, structure optimization and performance testing, an anlysis was carried out. [Result] The thermodynamic analysis shows that hydrocarbon fuels can be produced from CO2 catalytic hydrogenation. Six iron-based catalysts are developed to improve the reaction rate of hydrocarbon fuel synthesis. Based on the computational fluid dynamics (CFD) simulation, the structure of the microchannel reactor is designed and optimized. The microchannel reactor has the advantages of simple-compact structure and strong heat-mass transfer capability. The experimental results show that the Zn-Fe catalyst exhibits the best performance of CO2 catalytic hydrogenation for the synthesis of low-carbon olefins. CO2 conversion and low-carbon olefins selectivity are 32% and 44% respectively. [Conclusion] The microchannel reactor designed in this work has the dual functions of CO2 utilization for hydrocarbon fuel synthesis, which is of great significance to China's response to climate change, the realization of the dual-carbon target and the development of hydrocarbon fuel industry.

The research investigates converting carbon dioxide through methanation using computational fluid dynamics (CFD) in a baffled straight microchannel. The study considers different reactant distribution scenarios, including 'CO 2 Side,' 'H 2 Side,' and 'No side' streams. After finding the optimal catalyst mesh density, the model performance was validated against experimental microchannel reactor data. Results indicated that the microchannel with "CO 2 Side with Baffles" provides higher carbon dioxide conversion while maintaining the reactor temperature at a lower level. Finally, the influence of operational conditions, including feed temperature (450-400-350 °C), GHSV (120-90-60 NL/g cat/h), and H 2 /CO 2 (3.5-4.0-4.5) in the feed, was evaluated using a response surface methodology (RSM) based on the design of experiment (DOE) with carbon dioxide distribution. Multi-objective optimization results demonstrate that the optimal feed temperature, GHSV, and hydrogen-to-carbon dioxide ratio are 380 °C, 60 NL/g cat/h, and 4.43, respectively. Under these conditions, the methane yield is 60.95%, and the reactor exit temperature is around 520 °C. [Display omitted] • Reducing CO 2 emission was performed through methanation in a microchannel reactor. • CFD was used for studying the different feed distributions from side streams. • The Microchannel with Baffles and distributing CO 2 provides higher CO 2 conversion. • Adding CO 2 side streams reduces the microchannel reactor temperature. • Multi-objective optimization results in T = 380 °C, GHSV = 60 Nl/gcat/h, and H 2 /CO 2 = 4.43. [ABSTRACT FROM AUTHOR]

Copyright of Southern Energy Construction is the property of Southern Energy Construction Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The electrochemical nitrogen reduction reaction (NRR) has emerged as a sustainable and environmental–friendly alternative for ammonia synthesis compared with conventional Haber–Bosch process. However, considerable challenges persist in developing cost-effective catalysts for NRR. Herein, Cu 7 · 2 S 4 /C was synthesized using a continuous microchannel reactor followed by carbonization sulfurization at 600 °C. The as-prepared Cu 7 · 2 S 4 /C catalyst, featuring abundant sulfur vacancies, exhibited outstanding electrochemical performance for NRR, achieving an ammonia yield of 52 μg h − 1 mg cat. − 1 and Faraday efficiency of 32.2%. In addition, density functional theory calculations suggest that sulfur vacancies contribute to a decrease in Gibbs free energy during N 2 -activated hydrogenation, thereby facilitating adsorption of N 2 and formation of Cu–N bonds at catalytic active centers. This study introduces a novel strategy for synthesizing economical and efficient NRR electrocatalysts based on transition metal-based metal–organic frameworks. [Display omitted] • Cu-BTC was successfully synthesized using a continuous microchannel reactor. • BTC-derived Cu 7 · 2 S 4 /C with sulfur vacancy exhibited enhanced nitrogen reduction reaction performance for ammonia synthesis. • Cu 7.2 S 4 /C facilitated N 2 chemisorption and reduced Gibbs free energy for N 2 -activated hydrogenation. [ABSTRACT FROM AUTHOR]

The depletion of fossil fuels, along with the environmental damages brought by their usage, calls for the development of a clean, sustainable and renewable source of energy. Biofuel, predominantly liquid biofuel such as biodiesel, is a promising alternative to fossil fuels, due to its compatible direct usage within the context of compression ignition engines. However, the industrial production of biodiesel is far from being energy and time efficient, which contributes to its high production cost. These inefficiencies are attributed to poor heat and mass transfer of the transesterification reaction. The utilisation of microchannel reactors is found to be excellent in escalating heat and mass transfer of the reactants, benefitting from their high surface area-to-volume ratio. The microchannel also intensifies the mixing of reactants via the reactor design, micromixers and the slug flow patterns within the reactor, thus enhancing the contact between reactants. Simulation studies have aided in the identification of mixing regimes within the microchannel reactors, induced by various reactor designs. In addition, microwave irradiation heating is found to enhance biodiesel production by localised superheating delivered directly to the reactants at a molecular level. This enables the reaction to begin much earlier, resulting in rapid biodiesel production. It is postulated that the synergy between microchannel reactors and microwave heating would catapult a pathway towards rapid and energy-efficient biodiesel production by enhancing heat and mass transfer between reactants. [ABSTRACT FROM AUTHOR]

A hydrogen generator is used in the combined electrolysis catalytic exchange process (CECE) for low-level tritiated water detritiation as a source of H2 (Q2) for the liquid-phase catalytic exchange column(s) within the process. To produce H2, the H2 generator employs an electrolytic process for H2O splitting into H2 and O2, resulting two streams: a hydrogen stream and an oxygen stream. During the detritiation of water, tritium is accumulated in the H2 generator in the form of tritiated water, and the effluent streams (hydrogen and oxygen) show in time an increased tritium concentration in the form of both tritiated water vapors and gas, which need to be recovered. The traditional methods for recovery present a risk of explosion due to the high concentration of hydrogen in oxygen (above 3%, while the explosion limit is 1%). In order to minimize this risk, a microchannel reactor with platinated channels has been developed and tested for the oxidation of tritiated hydrogen from the O2 electrolyzer stream in view of its recovery in a scrubber column and returned as tritiated water to the process. The reactor has been coupled to an electrolyzer and tested with regard to the operating temperature. It has been found that it reaches the highest oxidation efficiency of hydrogen when operated at 200°C. The design of the equipment is presented together with the results of the tests done with the equipment integrated in the CECE process. [ABSTRACT FROM AUTHOR]

Pseudo‐boehmite with a high specific surface area and large pore volume was continuously synthesized in a microchannel reactor using the carbonation method. The effects of the microchannel on the prepared pseudo‐boehmite, strongly present in gas‐liquid mixing efficiency, were studied. In time scale, the crystallinity of pseudo‐boehmite in the microchannel, without the aging process of high‐temperature stirring, reaches the standard of industrial products. Besides, the fluid and mass transfer effect of the gas‐liquid mixing process in the microreactor was simulated under experimental conditions in computational fluid dynamics. The result illustrated the base‐liquid surround by the acid‐gas model in the microreactor, which is significantly different from the batch reactor. [ABSTRACT FROM AUTHOR]

In the green synthesis reaction of adipic acid, the oxidant H2O2 undergoes exothermic decomposition easily and the high exothermic amount of the reaction can easily lead to thermal runaway. This study carries out calorimetric experiments on the green synthesis reaction of adipic acid, studies the effect of the stabilizer ethylenediaminetetraacetic acid (EDTA) on the safety of the synthesis reaction, and further explores the effect of EDTA on the Na2WO4-catalyzed decomposition reaction of H2O2 under the conditions of continuous flow, and develops the microchannel continuous flow process of green synthesis of adipic acid containing EDTA, in order to provide theoretical support for the improvement of intrinsic safety of green synthesis of adipic acid.

Microchannel reactors, known as high-process intensification reactors, are utilized in various fields due to their intensive micromixing performance, which is crucial for fast chemical reactions. The work presented here depicts the Computational Fluid Dynamics (CFD) modeling of five generic microchannel reactors (MCRs), namely T-square, T-trapezoidal, Y-rectangular, concentric, and caterpillar designs based on the experimental published data of the parallel competing Villermaux-Dushman reaction. The main objective of this study is to numerically quantify the effects of the total liquid flow rate (1-18 mL/min), micromixer dimension (150-1600 µm) and configuration on the values of the pressure drop, energy dissipation, mixing time, and segregation index (XS). The CFD results revealed that under constant concentrations of the reactants ( , , , = 0.091, 0.0224, 0.016, 0.0033 M), the dissipation rate intensified with increasing the total flow rate but weakened with the change in symmetry and the channel diameter. Further, the estimated values of the segregation index illustrated that the caterpillar design could bring about a reasonable enhancement in micromixing performance with energy dissipation (ε) and segregation index of 1335700 W/kg and 0.0024, followed by T-square and Y-rectangular with Xs~ 0.0061 and 0.0161, respectively. The low values of mixing time for caterpillar MCR were found in the range of 0.01-0.1 s for liquid flow rates of 1-18 mL/min.

[Display omitted] • Alkyl-tetralin sulfonate anionic surfactants synthesized using tetralin and Fischer-Tropsch synthesized α-olefins as raw materials via coal chemical route. • Structure–property relationship of alkyl-tetralin sulfonate surfactants was elucidated. • C6 alkyl-tetralin sulfonate exhibits surfactant properties comparable to commercial linear alkylbenzene sulfonate (LAS). Benzene sulfonate surfactants are crucial anionic surfactants, commonly derived from petrochemical sources. Herein, we present a new method for synthesizing alkyl-tetralin sulfonate anionic surfactants using α-olefins (n-hexene, n-octene, n-decene) and tetralin sourced from the coal chemical industry as raw materials. The three-resulting alkyl-tetralin sulfonates (C6-THNS, C8-THNS and C10-THNS), obtained by alkylation and sulfonation of tetralin were characterized through HPLC, FTIR, LCMS and 1H NMR techniques. Their surfactant properties were also investigated and compared with commercially applied linear alkylbenzene sulfonate (LAS). We observed that C6 alkyl-tetralin sulfonate (C6-THNS) exhibited smaller critical micelle concentration (CMC =0.60 mM) and lower equilibrium surface tension (γ CMC =33.43 mN/m). Similarly, C6-THNS also showed comparable foaming, wetting and emulsifying properties with LAS, which can be used as a substitute for LAS surfactants. This study shows that the synthesized alkyl-tetralin sulfonates is a potential surfactant, providing a route for efficiently using coal-based chemicals to synthesize surfactants. [ABSTRACT FROM AUTHOR]

In this study, the performance of thin film Ni/ZrO2 and NiCu/ZrO2 catalysts in a microchannel reactor in the dry methane reforming reaction (DRM) is investigated. Thin film nanocatalysts are prepared by the physical vapor deposition (PVD) method. GIXRD, FESEM‐Cross, FESEM‐Surface, and EDX analyzes are used to evaluate the properties of thin film nanostructures. The results show that in addition to the addition of copper as a promoter, a change in the coating time causes a change in the formation of the thin layer and the growth mechanism of the layers. Reactor tests are evaluated at temperatures ranging from 700°C to 800°C, at P = 1 atm, with a CH4:CO2 ratio of 1. Results of this study are compared with two other studies in fixed bed reactors that show the microchannel reactor has better performance. The presence of copper on Ni/ZrO2 could have significant effects on the stability of hydrogen production and the reduction of carbon deposition. Thin film Ni/ZrO2 catalyst with 2 min coating time and NiCu/ZrO2 catalyst with NiCu weight ratio of 4: 1 with 1 min coating time at 800°C show the best performance in terms of hydrogen production and H2/CO ratio (1.43 for a sample of Ni/ZrO2 and 1.68 for a sample of NiCu/ZrO2). [ABSTRACT FROM AUTHOR]

Compared with conventional reactors that are designed by traditional micromachining technology, the use of 3D-printing technology to manufacture multichannel large-volume microchannel reactors as reaction equipment to remove low-concentration NOX by the wet method is simple and convenient, and the processing cost is low. The results showed that when the concentration of NO was 400 ppm, the mixed solution of (NH2)2CO mass fraction of 3% and H2O2 concentration of 0.5 mol/L was used, and the flow rates of gas and liquid were 100 mL/min, respectively, under the experimental conditions of pH = 11, solution temperature of 20 °C and 500 mL solution recycling for 20 min, the best removal effect of NOX was achieved, and the removal efficiency was 100%. When the O2 content in the flue gas was increased and the number and length of microchannels were increased, the NOX removal efficiency increased accordingly, which was conducive to the rapid and efficient reaction. The application of the microchannel reactor presents a new method for improving the air quality and reducing environmental pollution in the future. [ABSTRACT FROM AUTHOR]

Microchannel reactors, known as high-process intensification reactors, are utilized in various fields due to their intensive micromixing performance, which is crucial for fast chemical reactions. The work presented here depicts the Computational Fluid Dynamics (CFD) modeling of five generic microchannel reactors (MCRs), namely T-square, T-trapezoidal, Yrectangular, concentric, and caterpillar designs based on the experimental published data of the parallel competing Villermaux-Dushman reaction. The main objective of this study is to numerically quantify the effects of the total liquid flow rate (1-18 mL/min), micromixer dimension (150-1600 μm), and configuration on the values of the pressure drop, energy dissipation, mixing time, and segregation index (XS). The CFD results revealed that under constant concentrations of the reactants (CH2BO3-, CH+0, CI-,0,CIO3-,0 = 0.091, 0.0224, 0.016, 0.0033 M), the dissipation rate intensified with increasing the total flow rate but weakened with the change in symmetry and the channel diameter. Further, the estimated values of the segregation index illustrated that the caterpillar design could bring about a reasonable enhancement in micromixing performance with energy dissipation (ε) and segregation index of 1335700 W/kg and 0.0024, followed by T-square and Y-rectangular with Xs~ 0.0061 and 0.0161, respectively. The low values of mixing time for caterpillar MCR were found in the range of 0.01-0.1 s for liquid flow rates of 1-18 mL/min. [ABSTRACT FROM AUTHOR]

[Display omitted] • Density functional theory was employed to elucidate the transition states and reaction pathways of different configuration. • High efficiency one-pot synthesis of the norbornene-2,3-dicarboxylic anhydride was achieved in a continuous flow microreactor based on process intensification and system integration. • The exo / endo ratio could up to 1.19:1 as well as almost 100 % conversion and 98 % selectivity just in 2 min at 260 °C and 4 MPa. 5-Norbornene- exo -2,3-dicarboxylic anhydride (exo -NDA), widely used in the synthesis of medicine and pesticide, was primarily obtained through the subsequent thermal isomerization of 5-norbornene- endo -2,3-dicarboxylic anhydride (endo -NDA) synthesized from cyclopentadiene (CPD) and maleic anhydride (MAH). Herein, density functional theory (DFT) was employed to elucidate the transition states and reaction pathways of different configurations. The endo -path exhibited a lower energy barrier, and the exo -isomer demonstrates greater structural stability. It was found that both high temperature and solvent polarity influenced the generation of NDA with different configurations. Due to considering solubility of MAH, an acetone/ethylbenzene mixed solvent was chosen for the reaction instead. According to the DFT calculations, we developed continuous-flow microreactor for high-efficiency one-pot synthesis of the isomers with exo / endo ratio of up to 1.19:1 as well as almost 100 % conversion and 98 % selectivity just in 2 min at 260 °C and 4 MPa, which CPD was generated in situ to participate in a series of Diels-Alder reactions instead of dicyclopentadiene as raw material existed at room temperature. Moreover, excessive or insufficient pressure in the reaction system should elevate byproduct formation, resulting in a decrease in reaction selectivity, as could prolonged residence time. [ABSTRACT FROM AUTHOR]

• Microchannel reactor combined with green nitration for safe and green synthesis. • Process was optimized by response surface methodology. • Exothermic behavior of nitration reaction was investigated in the semi-batch mode. • Effect of volumetric flow rate during scale-up of the process was investigated. Aromatic nitro compounds are an important class of basic chemical raw materials, while traditional nitration methods may cause safety accidents and environmental pollution due to strong exothermicity and presence of sulfuric acid. In this work, aiming to alleviate these issues, the nitration of toluene was conducted in a microchannel reactor with nitric acid and acetic anhydride. The effect of temperature, molar ratio of nitric acid to toluene, mass fraction of acetic anhydride, and residence time on the conversion and selectivity of reaction were systematically investigated, and response surface methodology was used to optimize the process. A mononitrotoluene yield of 99.21 % can be achieved under optimum condition. Meanwhile, in order to better understand the exothermic behavior, toluene nitration by HNO 3 -AC 2 O was investigated in the semi-batch calorimeter. Finally, the optimized process was scaled up and effect of volumetric flow rate was investigated. At the selected maximum volumetric flow rate, the overtemperature of the system was 10.9 °C with a 98.3 % yield of mononitrotoluene. Continuous flow mode had a space-time yield nearly two orders of magnitude greater than semi-batch mode. This work can provide guidance for safe, efficient and green synthesis of mononitrotoluene. [Display omitted] [ABSTRACT FROM AUTHOR]

In this study, we studied the conversion of Jatropha curcas oil to biodiesel by using three distinct reactor systems: microchannel, fixed bed, and microwave reactors. ZSM-5 was used as the catalyst for this conversion and was thoroughly characterized. X-ray diffraction was used to identify the crystalline structure, Brunauer–Emmett–Teller analysis to determine surface area, and temperature-programmed desorption to evaluate thermal stability and acidic properties. These characterizations provided crucial insights into the catalyst's structural integrity and performance under reaction conditions. The microchannel reactor exhibited superior biodiesel yield compared to the fixed bed and microwave reactors, and achieved peak efficiency at 60 °C, delivering high FAEE yield (99.7%) and conversion rates (99.92%). Ethanol catalyst volume at 1% was optimal, while varying flow rates exhibited trade-offs, emphasizing the need for nuanced control. Comparative studies against microwave and fixed-bed reactors consistently favored the microchannel reactor, emphasizing its remarkable FAME percentages, high conversion rates, and adaptability to diverse operating conditions. The zig-zag configuration enhances its efficiency, making it the optimal choice for biodiesel production and showcasing promising prospects for advancing sustainable biofuel synthesis technologies. • Achieved high biodiesel efficiency with zig-zag microchannel reactor. • Optimized key parameters for max conversion rates and FAME percentages. • Reused ZSM-5 catalyst-maintained efficacy confirmed by XRD, BET, and TPD analyses. • Outperformed microwave and fixed-bed reactors in diverse conditions. • Showcased microchannel reactor's versatility and sustainability for biofuel synthesis. [ABSTRACT FROM AUTHOR]

Copyright of Basic Sciences Journal of Textile Universities / Fangzhi Gaoxiao Jichu Kexue Xuebao is the property of Basic Sciences Journal of Textile Universities and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A preliminary study regarding the dehydrogenation of perhydro-dibenzyltoluene as a liquid organic hydrogen carrier with switching from a stirred tank reactor to a continuous flow microchannel reactor is presented. The hydrogen production percentage in the case of a continuous flow microchannel reactor was found greater when compared to that of a stirred tank reactor. The hydrogen production was increased from 64.1% to 82.2% with the increase in bottom plate temperature from 260 to 320 °C for 0.01 mL/min flow rate. A maximum of 88% of hydrogen was generated for a 40 hours of operation, at a bottom wall temperature of 290 °C. The kinetic model for the microchannel reactor dehydrogenation was presented with a pre-exponential factor of 3.272 s−1 and activation energy of 13.79 kJ/mol. The results revealed that a continuous microchannel reactor can be an appropriate technology for the dehydrogenation of perhydro-dibenzyltoluene. • A microchannel reactor for the dehydrogenation of perhydro-dibenzyltoluene. • Comparison of two different reactors: a stirred tank and a continuous microchannel reactor. • A continuous microchannel reactor is a promising technology for the dehydrogenation. [ABSTRACT FROM AUTHOR]

The Sabatier micro-reactor for CO 2 reduction through methanation, in manned mission applications, has gained a lot of interest due to higher yields of fuel and improved logistics. Three-dimensional (3D) computational fluid dynamics (CFD) calculations of flow, heat transfer and chemical reactions are performed here to understand and evaluate the potential of H 2 and CO 2 enrichment to increase the efficiency of the CO 2 methanation in Sabatier microchannel reactors. The model is first validated by comparing calculations of the stoichiometrically-fueled reaction with previously conducted experiments at varying temperatures and pressures. A comprehensive set of studies at different H 2 and CO 2 enrichment levels, temperatures ranging from 200 to 400∘C and gauge pressures of 1 bar and 5 bar is carried out. Results show that yields and conversions of almost 100% are achievable with the highest H 2 enrichment levels at the highest temperature and pressure tested here, with a desirable control of CO emission. • 3D CFD calculations of a Sabatier microreactor have been performed. • Effects of H 2 and CO 2 enrichment CO 2 conversion and CH_4 yield are studied. • Model is validated by comparing to previous experiments at stoichiometric conditions. • Study demonstrates the utility of CFD calculations in optimizing the Sabatier reactor. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Explosives & Propellants is the property of Chinese Journal of Explosives & Propellants Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Using coal resources to synthesize high-value surfactants is effective for clean coal utilization and low-carbon conversion, attracting more attention from academia and industry. Herein, three coal-based isomeric alkylbenzene sulfonate surfactants were successfully synthesized via sulfonation with gas phase SO 3 utilizing isomeric alkylbenzenes, derived from the alkylation of benzene and Fischer–Tropsch synthesized α-olefins, as raw materials in a microchannel reactor. Moreover, their surfactant properties were systematically investigated to reveal the structure–property relationship. The results indicated that the equilibrium surface tension (γ CMC) for the synthesized surfactants was reduced with the increase of the degree of hydrophobic tails branching, and the order of γ CMC was: sodium dodecylbenzene sulfonate (35.67 mN·m−1) > sodium C6 olefin dimer alkylbenzene sulfonate (34.18 mN·m−1) > sodium dihexylalkylbenzene sulfonate (29.94 mN·m−1). Sodium dihexylalkylbenzene sulfonate with the lower γ CMC exhibited superior wettability (the contact angle of 50.2 ° at 30 s) and excellent emulsifying capacity (emulsification time of 1337 s) at the corresponding critical micelle concentration. This study provides new insights into rational design of hydrophobic tail architectures of surfactant molecules to meet specific needs in various fields. [Display omitted] • Isomeric alkylbenzene sulfonate surfactants with same carbon numbers were successfully synthesized via coal chemical route. • Isomeric alkylbenzene sulfonates with different hydrophobic tail architectures exhibited varied surfactant properties. • New insights into rational design of surfactant molecules with hydrophobic tail architectures for specific needs. [ABSTRACT FROM AUTHOR]

• A microchannel reactor with intensified micro-mixing and mass transfer. • Surfactant-free nano-ZnO were synthesized via a low-temperature one-step process. • They exhibited good uniformity without surface modification. • They showed high activity and low environmental energy impact for PET glycolysis. • A comprehensive study of the catalytic glycolysis process was conducted. Among PET chemical recycling technologies, glycolysis has shown the greatest potential for achieving commercial viability on large scales. The catalyst development is always one of the challenges in PET glycolysis. Herein, surfactant-free ZnO nanoparticles (SF-ZnO) were synthesized through a one-step process in an aqueous medium at low temperatures and ambient pressure. Meanwhile, a microchannel reactor with intensified micro-mixing and mass transfer was used to finely control the synthesis of SF-ZnO with uniform size distribution and consistent production reproducibility. Compared to the modified ZnO nanoparticles (M−ZnO) treated with the surfactant KH570, SF-ZnO exhibited enhanced catalytic activity and reusability in PET glycolysis, which can be attributed to its higher concentration of acid sites and superior thermal stability. Response surface methodology (RSM) was employed to investigate the impact of four key factors (temperature, time, catalyst: PET mass ratio, EG: PET mass ratio) and their interactions on bis(2-hydroxyethyl) terephthalate (BHET) yield in PET glycolysis. Under optimal conditions (196 °C, 40 min, SF-ZnO: PET = 0.76 wt%, EG: PET = 4), PET conversion and BHET yield reached 100 % and 97.3 %, respectively. Aspen simulation and preliminary scale-up experiments confirmed the commercialization potential of PET glycolysis on SF-ZnO. Meanwhile, the environmental energy impact metric and life cycle assessment (LCA) showed that the SF-ZnO catalytic system provided an economically feasible and environmentally friendly solution to PET glycolysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • CO 2 chemical absorption by MEA aqueous solution in minichannel investigated. • Taylor bubble generation, moving and shrinkage monitored, visualized and analyzed. • Inhabitation effect of chemical reaction-enhanced mass transfer on bubble generation. • New Da number-based correlation proposed to predict the initial bubble length. • A simple model developed to determine the channel effective length for CO 2 absorption. Taylor bubble dynamic characteristics of C O 2 chemical absorption into M E A aqueous solution in a vertical minichannel were systematically investigated in this study. The generation, movement, and shrinkage of bubbles in the minichannel were visualized and monitored using a high-speed camera, and their dynamic behaviors were characterized by image analysis method. The effects of gas and liquid Re numbers and absorbent concentration on two-phase flow patterns, bubble generation frequency, initial bubble length, bubble length decrease rate, and bubble velocity were examined and analyzed. Results showed that chemical reaction-enhanced mass transfer hindered the bubble cap penetration into the main channel, and alleviated the bubble neck thinning, both effects inhibiting the bubble generation. A new Damköhler number (Da)-based correlation has been proposed to predict the initial Taylor bubble length, showing good prediction accuracy for experimental data in the literature using different absorbents. Results also showed that before the formation of sphere bubble at the end of absorption, an approximate linear relationship exists between bubble length decrease rate and bubble velocity, with the slop decided by chemical reaction rate that could be characterized by the Da number. Finally, a simple model has been developed to determine the effective channel length at a given operating condition, providing design guidelines for microchannel-based miniaturized C O 2 absorbers. [ABSTRACT FROM AUTHOR]

Abstract Background Baricitinib, with a 2-(1-(ethylsulfonyl)azetidin-3-yl)acetonitrile moiety at N-2 position of the pyrazol skeleton, is an oral and selective reversible inhibitor of the JAK1 and JAK2 and displays potent anti-inflammatory activity. Several research-scale synthetic methods have been reported for the preparation of key quaternary heterocyclic intermediates of baricitinib. However, they were all associated with several drawbacks, such as the expensive materials, usage of pollutional reagents, and poor yields. Results In this manuscript, we established a green and cost-effective synthesis of 2-(1-(ethylsulfonyl)azetidin-3-ylidene)acetonitrile and tert-butyl 3-(cyanomethylene)azetidine-1-carboxylate for further scale-up production of baricitinib. This synthetic method employs commercially available and low-cost starting material benzylamine and an industry-oriented reaction of green oxidation reaction in microchannel reactor to yield important quaternary heterocyclic intermediates. Conclusion Generally, this procedure is reasonable, green and suitable for industrial production.

Microchannel reactors show fast mass transfer and heat transfer while limited active surface area, which can be greatly increased by reducing channel sizes. However, conventional extrusion makes honeycomb ceramics with channel sizes above 100 μm. This study has prepared ceramic microchannel reactors with channel sizes in the range of 1–100 μm by a one-step phase-inversion process, and channels are formed through the convection between coagulant and solvent. The effect of channel size on reaction performance was investigated by comparing two reactors with different channel sizes in dry reforming of methane. In addition, the microstructure of the reactors can be further tuned via sintering temperature to achieve high catalytic performance owing to the balanced active surface and mass transfer. Therefore, the microchannel reactors developed in this study represent a diagram-shift in the preparation of microchannel reactors by making channels with sizes less than 100 μm, which has potential applications in many catalytic reactions. [ABSTRACT FROM AUTHOR]

A study on the synthesis of nitrous oxide via the selective oxidation of ammonia in a microreactor in the form of a metallic disk with cylindrical channels filled with a manganese–bismuth oxide catalyst has been. A 3D mathematical model is presented for this microreactor that considers the transfer of mass and axial and radial heat, the catalytic reactions, the change they produce in the volume of the reaction mixture, the transfer of heat between the disk and the channels, and the heat conductivity of the disk. Parameters are determined that ensure the maximum nitrous oxide production with allowance for the limitations of temperature in the microreactor channels. The highest efficiency of nitrous oxide production is attained at an outer reactor edge temperature of 370°C and an inlet ammonia concentration of 20 vol %. The production capacity per unit catalyst volume in the microreactor is nearly 1.5 times higher than in a tubular reactor, and the maximum temperature corresponds to the level that provides the best process selectivity toward nitrous oxide. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Shanghai University of Engineering Science / Shanghai Gongcheng Jishu Daxue Xuebao is the property of Journal of Shanghai University of Engineering Science Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We consider the optimization of a chemical microchannel reactor by means of PDE-constrained optimization techniques, using the example of the Sabatier reaction. To model the chemically reacting flow in the microchannels, we introduce a three- and a one-dimensional model. As these are given by strongly coupled and highly nonlinear systems of partial differential equations (PDEs), we present our software package cashocs which implements the adjoint approach and facilitates the numerical solution of the subsequent optimization problems. We solve a parameter identification problem numerically to determine necessary kinetic parameters for the models from experimental data given in the literature. The obtained results show excellent agreement to the measurements. Finally, we present two optimization problems for optimizing the reactor’s product yield. First, we use a tracking-type cost functional to maximize the reactant conversion, keep the flow rate of the reactor fixed, and use its wall temperature as optimization variable. Second, we consider the wall temperature and the inlet gas velocity as optimization variables, use an objective functional for maximizing the flow rate in the reactor, and ensure the quality of the product by means of a state constraint. The results obtained from solving these problems numerically show great potential for improving the design of the microreactor. [ABSTRACT FROM AUTHOR]

New Cd–Zn/TiO2 and Cu–Zn/TiO2 catalysts based on nanodispersed titanium(IV) oxide are synthesized and characterized via X-ray diffraction analysis, low-temperature nitrogen adsorption, and temperature-programmed reduction with hydrogen. The activity of the synthesized catalysts in methanol steam reforming is studied under conditions of a microchannel reactor. It is shown that the highest activity is exhibited by Cd-containing catalysts, which are also characterized by the lowest carbon monoxide selectivity. The catalytic and physicochemical properties of the studied catalysts are compared. A correlation between the catalyst activity and the ability of Ti4+ cations in a TiO2 support to undergo partial hydrogen reduction to Ti3+ is shown. It is speculated that the reducibility of titanium cations depends on the semiconductor properties of the oxides in the catalyst. [ABSTRACT FROM AUTHOR]