Actual Reaction Research Articles

Catalytic Production and Upgrading of Furfural: A Platform Compound

Furfural is a renewable platform compound that can be derived from lignocellulosic biomass. The highly functionalized molecular structure of furfural enables us to prepare a variety of high value-added chemicals, which will help realize biomass high-value utilization, and alleviate energy and environmental problems. This paper reviews the research progress on furfural production and upgrading to C5 chemicals from the catalyst perspective. The emphasis is placed on summarizing and refining the catalytic mechanism and in-depth analysis of available data. Specifically, the reaction mechanism of furfural production and upgrading is summarized firstly from the perspective of reaction pathways and reaction kinetics. Then, the available data are further processed to evaluate the actual reaction efficiency of different catalytic systems from multiple dimensions. Finally, based on statistical analysis, the challenges and opportunities of furfural-based research are proposed.

HiMolformer: Integrating graph and sequence representations for predicting liver microsome stability with SMILES

In the initial stages of drug discovery or pre-clinical studies, understanding the metabolic stability of new molecules is crucial. Recently, research on pre-trained deep learning for molecular property prediction has been actively progressing, with various models being made open-source. However, most of these models rely on either 2D graph or 1D sequence for training, and the representation varies depending on the data format used. Consequently, combining multiple representations can broaden the scope of learning and may potentially be a manageable and most effective method to enhance performance.Therefore, we propose a novel hybrid model for predicting metabolic stability, which integrates representations from both graph-based and sequence-based models pre-trained for molecular features. This approach utilizes the combined strengths of 2D topological and 1D sequential information of molecules. HiMol, a graph-based graph neural network (GNN) model, and Molformer, a sequence-based Transformer model, were selected for integration, thus we named it HiMolformer. HiMolformer demonstrated superior performance compared to other models. We also focus on regression task for prediction with a empirical dataset from Korea Chemical Bank (KCB), comprising 3,498 molecules with mouse liver microsome (MLM) and human liver microsome (HLM) data obtained from actual metabolic reaction experiments. To the best of our knowledge, it is the first attempt to develop MLM and HLM prediction models using regression with a single SMILES input. The source code of this model is available at https://github.com/YUNSEOKWOO/HiMolformer.

Enhancing the high temperature resistance of nanocomposite materials through dimethyl methyl phosphate impregnation‐coating treatment

AbstractIn order to enhance the thermal stability of polyvinyl alcohol (PVA), a modification scheme involving a dimethyl methyl phosphate (DMMP) impregnation‐coating treatment was adopted in this article. Initially, the interfacial compatibility of DMMP with PVA was characterized using scanning electron microscopy (SEM), inductively coupled plasma spectroscopy, elemental analysis and Fourier transform infrared spectroscopy (FTIR). Subsequently, the pyrolysis and combustion properties of DMMP‐coated PVA were evaluated via non‐isothermal thermogravimetric experiments and cone calorimeter tests. The pyrolysis products were then analyzed using a combination of thermogravimetric infrared chromatography and pyrolysis gas chromatography/mass spectrometry (Py‐GC/MS). Finally, a reaction model function closer to the actual co‐pyrolysis mechanism at high temperatures was established through thermal kinetics. The results indicated that the impregnation‐coating treatment could effectively distribute the DMMP molecules on the surfaces of PVA particles. Meanwhile, the DMMP coating could clearly slow the peak degradation rate of PVA grains and inhibit the combustion of PVA under fire conditions. Furthermore, the pyrolysis of DMMP‐coated PVA resulted in the formation of over 40 distinct compounds. The kinetic analysis revealed that the reaction model function established in this article could better characterize the actual reaction mechanism of the co‐pyrolysis of DMMP and PVA.

In-depth analysis on the mechanism and reaction efficiency of hydrogen deoxidation in ultra-low carbon steel

The reaction mechanism and efficiency of hydrogen deoxidation used in ultra-low carbon steel are explored in this work. A combination of first-principle simulations and thermodynamic calculations were performed on the reaction mechanisms of hydrogen with dissolved oxygen. Laboratory thermal state experiments were used to analyze the effects of different initial oxygen contents of steel and different hydrogen injection flow rates on the deoxidation ability. The results show that the hydrogen deoxidation mainly happens with the gas state of H2 since there are more reactive sites of H atoms in the gas bubble compared to the dissolved H. Higher initial oxygen content and larger hydrogen blowing flow rate are beneficial to the deoxidation reaction efficiency. With hydrogen deoxidation, the inclusion number can be reduced by half compared to Al deoxidation, and the finally total oxygen content can reach 6.8 × 10-6. The actual reaction hydrogen utilization efficiency fluctuates between 0.13%-1.17% in this study, which can be improved by extending the resistance time of H2 bubbles in the molten steel. This paper provides in-depth theoretical support and atomic-scale insights into the reaction between hydrogen and oxygen in steel, building a foundation for the hydrogen application in the production of ultra-low-carbon steel.

Ultrafine Rhodium-Chromium Mixed-Oxide Cocatalyst with Facet-Selective Loading for Excellent Photocatalytic Water Splitting.

The development of water-splitting photocatalysts capable of generating green hydrogen (H2) from water and sunlight is crucial for achieving carbon neutrality. Further enhancement of the photocatalytic water-splitting activity is essential to realizing this objective. Photocatalysts with specific exposed crystal facets can facilitate efficient charge separation of electrons/holes, thereby achieving high activity for water splitting. However, there have been no reports of ultrafine (∼1 nm) cocatalysts being loaded onto specific crystal facets of photocatalysts, despite cocatalysts being the actual reaction sites for water splitting. This study establishes a novel method for achieving facet-selective loading of ultrafine H2-evolution cocatalysts onto the {100} facets, which are the H2-evolution facets, of a strontium titanate photocatalyst. The resulting photocatalyst exhibits the highest apparent quantum yield achieved to date for strontium titanate. This research holds the potential to further improve various types of advanced photocatalysts and is expected to accelerate the transition to carbon neutrality.

Fe-O4 Motif Activated Graphitic Carbon via Oxo-Bridge for Highly Selective H2O2 Electrosynthesis.

Carbon-based materials have been utilized as effective catalysts for hydrogen peroxide electrosynthesis via two-electron oxygen reduction reaction (2e ORR), however the insufficient selectivity and productivity still hindered the further industrial applications. In this work, we report the Fe-O4 motif activated graphitic carbon material which enabled highly selective H2O2 electrosynthesis operating at high current density with excellent anti-poisoning property. In the bulk production test, the concentration of H2O2 cumulated to 8.6 % in 24 h and the corresponding production rate of 33.5 mol gcat -1 h-1 outperformed all previously reported materials. Theoretical model backed by in situ characterization verified α-C surrounding the Fe-O4 motif as the actual reaction site in terms of thermodynamics and kinetics aspects. The strategy of activating carbon reaction site by metal center via oxo-bridge provides inspiring insights for the rational design of carbon materials for heterogeneous catalysis.

Fe−O4 Motif Activated Graphitic Carbon via Oxo‐Bridge for Highly Selective H2O2 Electrosynthesis

AbstractCarbon‐based materials have been utilized as effective catalysts for hydrogen peroxide electrosynthesis via two‐electron oxygen reduction reaction (2e ORR), however the insufficient selectivity and productivity still hindered the further industrial applications. In this work, we report the Fe−O4 motif activated graphitic carbon material which enabled highly selective H2O2 electrosynthesis operating at high current density with excellent anti‐poisoning property. In the bulk production test, the concentration of H2O2 cumulated to 8.6 % in 24 h and the corresponding production rate of 33.5 mol gcat−1 h−1 outperformed all previously reported materials. Theoretical model backed by in situ characterization verified α‐C surrounding the Fe−O4 motif as the actual reaction site in terms of thermodynamics and kinetics aspects. The strategy of activating carbon reaction site by metal center via oxo‐bridge provides inspiring insights for the rational design of carbon materials for heterogeneous catalysis.

(Invited) Exploring Catalyst Characteristics through in-Situ Studies of Solid-Liquid Interfaces

Scientists are driven by the urgent need to combat global climate warming and environmental pollution, leading to the development of highly efficient and eco-friendly energy technologies. Hydrogen, a key player in achieving deep decarbonization for net-zero carbon dioxide emissions by 2050, is currently produced through the widely used steam-methane reforming process, which, unfortunately, relies on fossil fuels and generates significant CO2 as a byproduct. This process is environmentally unfriendly and unsustainable, emphasizing the necessity for green hydrogen production. The sun emerges as a clean, renewable, and abundant energy source, offering an ideal solution to the environmental challenges posed by fossil fuels. Hydrogen, an excellent fuel for fuel cell applications, must be generated from renewable and carbon-free resources, particularly utilizing natural energies like sunlight. Enter the photoelectrochemical cell, a promising method for hydrogen generation. This cell comprises semiconductor photoelectrodes capable of harnessing light energy to directly split water. Photocatalysis, leveraging light energy for chemical reactions, holds the key to large-scale solar energy storage, overcoming challenges such as cost and efficiency. Despite over four decades of dedicated research, photocatalysis still faces hurdles in terms of cost and efficiency, hindering progress in this crucial field. A major obstacle lies in the limited understanding of the mechanisms underlying its low performance. To address this challenge, I will overview several experimental studies that have successfully unveiled catalytic reactions at solid/liquid interfaces in real time, focusing on the electrochemical interface of photocatalysis and electrocatalysis. These studies utilize operando X-ray characterization, providing unique insights into the actual reaction mechanisms.

Scanning Gas Diffusion Electrode Setup for Real-Time Analysis of Catalyst Layers.

The scanning gas diffusion electrode (S-GDE) half-cell is introduced as a new tool to improve the evaluation of electrodes used in electrochemical energy conversion technologies. It allows both fast screening and fundamental studies of real catalyst layers by applying coupled mass spectrometry techniques such as inductively coupled plasma mass spectrometry and online gas mass spectrometry. Hence, the proposed setup overcomes the limitations of aqueous model systems and full cell-level studies, bridging the gap between the two approaches. In this proof-of-concept work, standard fuel cell electrodes are investigated at elevated oxygen reduction reaction current densities, while dissolved Pt x+ ions in the electrolyte and gaseous CO2 in the outlet gas stream are detected to track platinum dissolution and carbon corrosion, respectively. Relevant current densities of up to 0.75 A cm-2 are demonstrated. The electrochemically active surface area, oxygen reduction reaction activity, and Pt dissolution rates are quantified and benchmarked to the values obtained in the conventional stationary GDE half-cell. Moreover, it is found that Pt dissolution is suppressed when O2 is purged into the catalyst layer. Overall, this work demonstrates the feasibility of fast fuel cell electrode screening obtaining, complementary to electrochemical, mass spectrometry data necessary in fundamental studies on structure/performance relationships under actual reaction conditions. While Pt/C, in relevance to its fuel cell application, is used in this study, the proposed setup can be applied in water electrolysis, CO2 conversion, metal-air batteries, and other neighbor technologies.

Colorimetric Fluorescence of a 2,4,5‐Triaryl Imidazole‐Based Sensor for the Selective Detection of Iron

AbstractTwo imidazole‐based color‐changing fluorescent probes 4‐(4,5‐bis(4‐chlorophenyl)‐1H‐imidazol‐2‐yl)‐N, N‐diphenylaniline (CIN) and 4‐(4,5‐di(furan‐2‐yl)‐1H‐imidazol‐2‐yl)‐N, N‐diphenylaniline (FIN) were synthesized and characterized. The new probes CIN and FIN exhibit excellent selectivity and sensitivity towards Fe3+ with relatively low detection limits (0.26 μM and 0.10 μM) and strong anti‐interference properties. Both the probes CIN and FIN complex 1 : 1 with Fe3+ ion, and the complexation constants were 1.165×105 M−1 (CIN) and 1.899×105 M−1 (FIN), respectively. Moreover, CIN and FIN could be recycled by EDTA and could effectively monitor Fe3+ ions at pH 4–10, which ensures the sensor‘s potential for detecting Fe3+ in actual aqueous solutions. The probes were further applied to the detection of Fe3+ in the actual reaction of Fe2+ oxidation, and the filter paper and the probe solution are combined to make an indicator to detect Fe3+ more conveniently and quickly.

In-Situ Characterization Techniques for Mechanism Studies of CO2 Hydrogenation.

The paramount concerns of global warming, fossil fuel depletion, and energy crises have prompted the need of hydrocarbons productions via CO2 conversion. In order to achieve global carbon neutrality, much attention needs to be diverted towards CO2 management. Catalytic hydrogenation of CO2 is an exciting opportunity to curb the increasing CO2 and produce value-added products. However, the comprehensive understanding of CO2 hydrogenation is still a matter of discussion due to its complex reaction mechanism and involvement of various species. This review comprehensively discusses three processes: reverse water gas shift (RWGS) reaction, modified Fischer Tropsch synthesis (MFTS), and methanol-mediated route (MeOH) for CO2 hydrogenation to hydrocarbons. Along with analysing the reaction pathways, it is also very important to understand the real-time evolvement of catalytic process and reaction intermediates by employing in-situ characterization techniques under actual reaction conditions. Subsequently, in second part of this review, we provided a systematic analysis of advancements in in-situ techniques aimed to monitor the evolution of catalysts during CO2 reduction process. The section also highlights the key components of in-situ cells, their working principles, and applications in identifying reaction mechanisms for CO2 hydrogenation. Finally, by reviewing respective achievements in the field, we identify key gaps and present some future directions for CO2 hydrogenation and in-situ studies.

A Novel Battery Model Considering the Battery Actual Reaction Mechanism for Model Parameters and SOC Joint Estimation

A Novel Battery Model Considering the Battery Actual Reaction Mechanism for Model Parameters and SOC Joint Estimation

Experimental road safety study of the actual driver reaction to the street ads using eye tracking, multiple linear regression and decision trees methods

The article describes the results of a naturalistic driving study done in Kuwait performed by 34 participants wearing a mobile eye tracker to monitor the effect of roadside advertisements on user attention. Eye-tracking (fixations) are the main dependent variable and examined as a function of driving/roadside characteristics, particularly billboards, speed, and so forth. The results obtained were analyzed using traditional statistics (ANOVA test and multiple linear regression) and machine learning (decision tree estimation methods). From the results, it was found that road advertisements negatively affect driver attention and thus road safety. How the level of safety varies with the type and size of advertisement was also investigated. As a consequence, all of the estimates revealed that different aspects of advertising have a detrimental impact on drivers' behavior, and that the duration of fixation and the rate of acceleration before viewing an ad are impacted by advertising type and size, respectively.

Polycation-functionalized interface enable in situ capturing of CO2 and filtering of proton for efficient C-N coupling toward highly selective urea electrosynthesis

Electrochemical co-reduction of CO2 and nitrate provides a novel route to convert waste emissions into value-added chemicals such as urea. However, at the actual reaction interface, the insufficient supply of CO2 reactants as well as the excessive coverage of proton and nitrate on the electrocatalyst surface usually lead to complex product distributions from individual hydrogen evolution or nitrate reduction as side reactions, instead of C-N coupling. Here, we rationally optimize this interface by polycation functionalization, forcing highly selective urea electrosynthesis. The abundant polyamine nodes within the functional layer are conductive to in situ capturing of CO2 and filtering of proton, which pertinently control the reagent concentration to promote the selective C-N coupling and inhibit the undesired side reactions. When this tailored interface is coupled with efficient electrocatalyst with neighboring active sites, the proof-of-concept system delivers a maximum urea generation yield rate of 1254.2 μg h−1 mg−1 along with a Faradaic efficiency of 83.4 %, as well as outstanding Nurea-selectivity of 91.3 % and Curea-selectivity of nearly 100 %, which is one of the most selective urea generation systems reported so far. This work provides new insights in regulating the catalysis microenvironment for the improvement of overall performance in electrochemical C-N coupling.

Temperature control strategy for safer and heat-efficient operations in a catalytic flow reactor

A new temperature control strategy for a packed-bed tubular reactor was proposed. Case studies of a highly exothermic 1st-order reaction and an actual 2nd-order reaction were conducted using the computational fluid dynamics software COMSOL Multiphysics® 4.4. Through the simulation, the important factors for reactor temperature control were confirmed, which were the parameters related to heat transfer. Based on the ratio of the heat generation rate to the heat transfer rate, a new dimensionless number was proposed for controlling the temperature increase within an acceptable range in a reactor. Through case studies, the validity of the proposed dimensionless number was confirmed, and an important value of a proportionality constant was derived from the results. Using the proposed dimensionless number, a reactor size can be maximized within an acceptable temperature increase. The results obtained in this study are expected to provide important guidelines for temperature control and maximization of production using flow reactors.

Facing a request for assisted death - views of Finnish physicians, a mixed method study

BackgroundAssisted death, including euthanasia and physician-assisted suicide (PAS), is under debate worldwide, and these practices are adopted in many Western countries. Physicians’ attitudes toward assisted death vary across the globe, but little is known about physicians’ actual reactions when facing a request for assisted death. There is a clear gap in evidence on how physicians act and respond to patients’ requests for assisted death in countries where these actions are not legal.MethodsA survey including statements concerning euthanasia and PAS and an open question about their actions when facing a request for assisted death was sent to all Finnish physicians. Quantitative data are presented as numbers and percentages. Statistical significance was tested by using the Pearson chi-square test, when appropriate. The qualitative analysis was performed by using an inductive content analysis approach, where categories emerge from the data.ResultsAltogether, 6889 physicians or medical students answered the survey, yielding a response rate of 26%. One-third of participants agreed or partly agreed that they could assist a patient in a suicide. The majority (69%) of the participants fully or partly agreed that euthanasia should only be accepted due to difficult physical symptoms, while 12% fully or partly agreed that life turning into a burden should be an acceptable reason for euthanasia. Of the participants, 16% had faced a request for euthanasia or PAS, and 3033 answers from 2565 respondents were achieved to the open questions concerning their actions regarding the request and ethical aspects of assisted death. In the qualitative analysis, six main categories, including 22 subcategories, were formed regarding the phenomenon of how physicians act when facing this request. The six main categories were as follows: providing an alternative to the request, enabling care and support, ignoring the request, giving a reasoned refusal, complying with the request, and seeing the request as a possibility.ConclusionsFinnish physicians’ actions regarding the requests for assisted death, and attitudes toward euthanasia and PAS vary substantially. Open discussion, education, and recommendations concerning a request for assisted death and ethics around it are also highly needed in countries where euthanasia and PAS are not legal.

Spectroscopic In-Vitro Drug-Drug Interaction Studies of Amoxicillin and Paracetamol Solid Dosage Forms

Potential drug-drug interactions (DDIs) are a public health concern in clinical therapy and drug development because of their contribution to actual adverse drug reactions (ADRs) or events. The study aimed to quantify the in-vitro drug-drug interaction of amoxicillin (AMX) and paracetamol (PCM) formulations which are commonly co-administered. Determinations were carried out by spectroscopic methods – zero-order and derivative spectroscopy. The data were analyzed using Microsoft Excel, 2016. The UV-Spectra of AMX and PCM showed two distinctive peaks at 240 nm and 260 nm were observed for AMX, while for PCM at 290nm and 340 nm, with maxima at 240 nm and 340 nm for AMX and PCM respectively. Absorption measurements were taken at the maximum wavelength of 290 nm and 240 nm for PCM and AMX respectively. The content of both drugs and potential DDIs of AMX and PCM were assayed by zero- and 3rd-derivative spectroscopy. The calibration curves for AMX and PCM standards showed good linearity at concentrations, with corresponding correlation coefficients (R) being 0.999 and 0.998. The intercept and slope for AMX were -0.0148 and 0.0732 respectively, while for PCM values were 0.0071 and 0.148. The content of PCM and AMX in the formulations was 98.40 ± 0.44% and 96.04 ± 0.29% respectively. The joint-drug-dissolution studies for AMX and PCM interaction (DDI) were obtained with the 3rd-order derivative spectroscopy at 210 nm (zero-crossing for PCM) and 290 nm (zero-line crossing for AMX) respectively - which showed overlapping spectra for their zero-order derivative spectra. No significant difference was observed in the in-vitro drug release profiles for AMX and PCM, while comparative profiles were observed to have a very strong correlation between individual-release and joint-release profiles.

RESEARCH ON THE POSSIBILITY OF ACHIEVING CHEMICAL SIMILARITY DURING HIGH-TEMPERATURE MODELING OF METALLURGICAL PROCESSES

Transfer of chemicals between phases is an extremely important indicator for metallurgical systems. At the same time, for high-quality modeling, it is necessary to ensure the similarity of the models, that is, a certain criterion of chemical similarity, which will ensure the adequacy of the modeling, becomes relevant. Different criteria can be used to achieve chemical similarity, the choice of which depends on the importance of one or another aspect that affects the actual chemical reaction. The possibility of using the similarity of Gibbs energies as an indicator of the possibility of the reaction at the temperatures of metallurgical processes and the similarity of the initial concentrations was proposed and studied in the work during high-temperature modeling of the oxidation of silicon from hot metal. It was also mandatory to use the modified Froude criterion. Due to the proposed method of similitude modeling, brass with a mass fraction of zinc of 1%, which has a lower melting point than cast iron, was chosen as a model environment, that is, it requires less modeling costs. Comparison of the obtained results with the results of purging in similar conditions of hot metal showed the closeness of the data, which indicates the feasibility of the proposed method.

Stress Prerelease‐Driven Dendrite‐Free Growth Mechanism to Stabilize Zn Anodes

AbstractThe mechanical properties of zinc anodes in rechargeable zinc‐based batteries are neglected. Indeed, electrode stress in zinc crystallization (ESZC) contributes to excess chemical potential under enormous deposition stress, severely impacting zinc crystal patterns and reaction kinetics. Herein, a stress prerelease mechanism to minimize ESZC and drive dendrite‐free zinc anode growth is proposed. The internal stress of the freestanding electrode is prereleased by full‐contact soft‐substrate constraints during fabrication. Under the compression of crystallization stress, the freestanding electrode rapidly deforms and self‐releases into microstrains to reduce ESZC. Furthermore, the weakening of ESZC under the stress‐prerelease mechanism is modified to the actual reaction kinetics, which establishes a direct link between electrode stress and zinc deposition pattern. The processes of crystalline stress transfer and self‐release under the stress prerelease mechanism are revealed using in situ strain monitors. Stress‐prereleased freestanding electrodes drive uniform zinc nucleation and subsequent radial diffusion, guiding Zn epitaxial growth on the nanofibers surface. During repeated deposition/stripping, the stress prerelease mechanism steadily diminishes the possibility of dendrite growth and guarantees the stable operation of dendrite‐free zinc anodes. The stress prereleased freestanding electrodes induce symmetric and full cells to achieve stable and excellent performance.

Photocatalytic fixed bed reactions for contaminant mineralization

It is generally concerned that the issues such as mass transport and volume activity resulted from photocatalyst immobilization will undesirably slow photocatalytic reactions. Although certain strategies imitating slurry suspension have been proposed, the photon utilization is evidently lower than the dispersed counterparts. We here review a recently proposed approach to photocatalyst immobilization by cognizing the time constants for the electronic processes and mass transport occurred in actual photocatalytic reaction. By virtue of effective separation of oxidation and reduction half-reactions, the photocatalytic fixed bed reactions formed by anchoring photocatalysts onto the smooth internal wall of the light incident side of the reactors can be superior to slurry suspension in photon utilization. The scalable photocatalytic fixed bed reactions in mineralization of contaminants in wastewater and air, and CO oxidation in hydrogen streams for lossless purification are also reviewed.