Efficient Reaction Research Articles

Modulating the acidity of bimetallic functionalized Zr-based metal–organic frameworks with hierarchical porosity through solvent-free approach to enhance butyl butyrate production

Design of multivariate metal–organic frameworks (MOFs) provide new avenues to gain ultrahigh catalytic activity for target reactions, however, developing one-pot green approach for synthesizing multivariate MOFs remains challenging. In this work, a one-pot green approach was developed to synthesize bimetallic functionalized UiO-66(Hf-Zr)–COOH with high acidity and hierarchical porosity without the employment of solvent. The optimal UiO-66(Hf1/4-Zr)–COOH displayed an ultrahigh upgradation of catalytic efficiency in esterification reaction of butyric acid and butanol for producing butyl butyrate due to its hydrophilicity, hierarchical porosity, carboxyl group and bimetallic cluster, and the conversion of butyric acid to produce butyl butyrate reached 91.5 % under the optimal reaction condition. UiO-66(Hf1/4-Zr)–COOH showed excellent reusability in the esterification reaction for the conversion of butyric acid, and its activity and stability could be retained after being recycled 6 times. Such outstanding esterification activity could be mainly ascribed to excellent ability for absorbing the reactants, and the easy accessibility of plentiful acid sites. Our work provides a solvent-free approach for one-pot synthesizing multivariate MOFs to boost their catalytic performance for targeted reactions.

Optimization design of a two-step microreactor with spiral structure for high-performance catalytic reactions

Abstract In order to enhance the efficiency of diphenyldimethoxysilane preparation in microreactors, this study utilized the computational fluid dynamics simulation based on the finite element method to explore the impact of the internal structural parameters of the spiral two-step microreactor (STMR) on the reaction outcomes, with the aim of optimizing its structure for high-performance catalytic reactions. By designing a microreactor based on the Archimedean spiral shape and introducing two ribbed obstacles, the structure was optimized through adjusting the relevant ratios. The effects of different-sized structures and obstacles within the reaction zone and non-reaction zone on the product concentration and reaction results were discussed. The results demonstrate that lower obstacle heights and smaller aspect ratios (P = 2:7, R = 5:6) are beneficial for improving the reaction efficiency and product concentration. This study offers a theoretical foundation for microreactor design and is anticipated to further drive the development of microreactor technology.

Boron/Difluoroamino (B/NF2) Composites Prepared Through an Energetic Fluorinated-Centerd Surface Modification Strategy to Enhance Their Ignition and Combustion Characteristics.

To enhance the ignition and combustion characteristics of boron (B), in this study, a suitable, energetic fluorinated group (NF2) that can improve energy and promote combustion efficiency was utilized and B/NF2 composites (B/PDB) with three different particle sizes (10-20 μm, <5 μm, and 0.5-2 μm) were prepared through energetic fluorinated surface modifications with a PDB layer, a copolymer of difluoroaminomethyl-3-methylethoxybutane and 3,3'-bis(azidomethyl)oxetane, coated on the surface of B. The morphology and structure of B/PDB were characterized via the FTIR, SEM, TEM, and XPS techniques. The results indicate that all B/PDB particle sizes were successfully coated by NF2 on the surfaces of B particles through the PDB layer. The TG curves in the thermal analyses were used to determine the amount of the PDB layer of B/PDB with different particle sizes. Based on the DSC curves, NF2 of composites with better catalysis during ammonium perchlorate (AP) decomposition. Additionally, the effects of NF2 on both B/PDB and B/PDB with AP were investigated through PY-GC/MS, ignition, and combustion. Compared with pure B, NF2 significantly improved the thermal conductivity, thereby decreasing the ignition delay of B/PDB, and the ignition delay of B/PDB with AP. The combustion of B/PDB and AP was more intense, extending the combustion duration, forming volatile fluorine compounds, and increasing combustion reaction efficiency. In general, this energetic fluorinated-centred surface modification has potential applications to enhance the ignition and combustion characteristics in B.

Trace Iron-Modified CeO₂-Supported Core-Shell CoO@Co Catalyst for Selective Conversion of Furfural to 1,5-Pentanediol.

In the conversion of furfural using non-noble metal catalysts, preferential cleavage of the C2-O bond followed by hydrogenation of the C=C bond facilitates selective access to valuable 1,5-pentanediol (1,5-PeD). Herein, we developed CeO₂ loaded core-shell CoO@Co nanoparticle catalysts. Adjusting Co loading, Fe doping, and reduction temperature improved reaction efficiency. 7Co-0.2Fe/CeO₂ catalysts reduced at 500 °C demonstrated optimal performance. 1,5-PeD produced at 54.76 mmol/gCo/h, representing the top activity levels among the reported catalysts. H₂-TPR, XRD, HAADF-STEM, FT-IR, XPS, and XANES were employed to investigate the catalyst structure-activity relationship. Co2+ cleaves furan ring C-O bond, Co⁰ promotes double-bond hydrogenation. The CoO@Co structure favors the desired 1,5-PeD production route. Trace Fe species optimize the Co2+/Co⁰ ratio, enhance the substrate adsorption, and inhibit the furan ring saturation. These findings emphasize the importance of fine-tuning catalyst structure and composition for selectivity improvement.

Membrane-dependent reactions of blood coagulation: classical view and state-of-the-art concepts

The complex mechanism called hemostasis evolved in living organisms to prevent blood loss when a blood vessel is damaged. In this process, two closely interconnected systems are distinguished: platelet-vascular and plasmatic hemostasis. Plasmatic hemostasis is a system of proteolytic reactions, in which blood plasma proteins called coagulation factors are involved. A key feature of this system is the localization of enzymatic reactions on the surface of phospholipid membranes, which increases their rate by up to 5 orders of magnitude. This review describes the basic mechanisms of coagulation factors binding to phospholipid membranes, pathways for complex assembly and activation reactions, and discusses the role of membranes in this process, their composition and sources. The binding of coagulation factors to procoagulant membranes leads not only to the acceleration of coagulation reactions, but also to their selective localization in restricted areas and protection from being washed away by the flow. The efficiency of coagulation reactions is regulated by the composition of the outer layer of the membrane, primarily through a special mechanism of mitochondria-dependent necrotic platelet death.

Improving alkaline hydrogen evoluation reaction efficiency through 1T/2H-MoS2/Ni3S2 heterostructure design

Improving alkaline hydrogen evoluation reaction efficiency through 1T/2H-MoS2/Ni3S2 heterostructure design

A novel simultaneous abatement of bromate and diphenyl phosphate using the freezing process

The purification of bromate (BrO3−)-contaminated water has become a challenge because of its persistence and adverse effects. Furthermore, there has been concern over the release of byproducts, such as diphenyl phosphate (DPHP), from flame retardants in wastewater treatment plant (WWTP). In this study, we designed the water treatment system for the oxidation of DPHP accompanied by bromate (BrO3−) reduction via freezing the solution. A sample containing 10 μM DPHP, 100 μM Br−, and 50 μM BrO3−, with a pH of 3 was frozen at −20oC, approximately 25 μM BrO3− was reduced, and DPHP was fully eliminated after a 0.5 h reaction time. Conversely, these reactions did not advance in water at 20oC. This increase in the rate of chemical reaction in ice is the consequence of the freeze concentration effect, which refers to the extraction of dissolved chemical species into the liquid-like regions of the polycrystalline ice micro-structure during the freezing of the solution. The redox reactions among DPHP, Br−, and BrO3− become thermodynamically favorable due to the distinctive environment in the liquid brine in ice. The efficiency of the DPHP oxidation significantly increased with an increase in BrO3− concentration, and vice versa. The Br−/BrO3−-induced HOBr production is proposed as a primary oxidant for DPHP degradation. The proton activity (pH) has a significant influence on the reaction efficiency. The low freezing temperature accelerated the reaction kinetics of DPHP degradation and BrO3− reduction. The results of this study indicate the possibility of utilizing ice chemistry for the BrO3− reduction that concomitantly removes DPHP for water treatment. This environmentally friendly water treatment method can be considered to implement in regions with a cold climate.

Exploring the role of solvents in structural regulation during ultrasonic synthesis of Co/Ni-layered double hydroxide for oxygen evolution reaction

Cobalt-based layered double hydroxides (LDHs) are highly sought after by researchers due to their low-cost, high efficiency and stability for oxygen evolution reaction (OER) in water electrolysis. The OER performance of these LDHs is closely related to their morphology and electronic structure. However, there is a lack of theory on how to control reaction conditions to regulate the morphologies. In this paper, the growth mechanism of LDH prepared in different solvents is thoroughly studied. Consequently, the Co/Ni-LDHs exhibiting a 3D hierarchical flower-like structure were synthesized with normal alcohol as a solvent, meanwhile, the thickness of the LDHs can be controlled by the molecular weight of the normal alcohol. By adjusting the suitable Co/Ni ratio and solvent, the Co/Ni0.050-LDH-Me was synthesized and exhibited excellent OER performance. At 10 mA cm−2, the overpotential of Co/Ni0.050-LDH-Me is 307 mV, and the Tafel slope is 76.5 mV dec−1.

A comparative study of BiFeO3-based compounds for enhanced hydrogen evolution reaction

We present a comprehensive study, combining experimental and theoretical approaches, to assess the hydrogen evolution reaction (HER) efficiency of BiFeO3-based solid solutions. Initially, we investigate the electronic and optical properties of these compounds, with a particular focus on band edge alignment relative to water redox potentials. Our findings show that the materials exhibit optimal band gaps of approximately 2.0 eV, indicative of enhanced visible light absorption and favorable energetic alignment to drive efficient hydrogen generation. To corroborate our theoretical predictions, we perform photoelectrochemical measurements on selected BiFeO3-based compounds synthesized via the solid-state method. Our experimental results reveal a high hydrogen yield, with BiFeO3-SrTiO3 achieving a production rate of ∼114 µmol/L in 30 min, outperforming BiFeO3-BaTiO3 (∼70 µmol/L) and pristine BiFeO3 (∼61 µmol/L). These findings validate our theoretical assumptions and demonstrate the superior HER performance of BiFeO3-SrTiO3, positioning it as a highly promising candidate for sustainable hydrogen production.

Pd/IPrBIDEA‐Catalyzed Synthesis of Pyrroles via Cascade C−C/C−F Cleavage/Annulation of gem‐Difluorocyclopropanes

AbstractA regioselective cascade C−C/C−F cleavage/annulation of gem‐F2CPs with enaminones catalyzed by Pd/IPrBIDEA is reported. The NHC ligand IPrBIDEA plays a pivotal role in enhancing the reaction efficiency. With this protocol, a variety of fully substituted pyrroles were obtained in good to excellent yields. Furthermore, this approach facilitates the modification of some bioactive scaffolds.

Advancements in Inverse-Electron-Demand Diels–Alder Cycloaddition of 2-Pyrones: Mechanisms, Methodologies

The Diels-Alder (DA) cycloaddition is well-known for its effectiveness in synthesizing natural products and multifunctional materials. This article specifically explores the inverse-electron-demand Diels-Alder (IEDDA) cycloaddition involving 2-pyrones, which display ambiphilic properties due to their unique electronic characteristics. We investigate the mechanisms underlying IEDDA, with a focus on how electron-donating and electron-withdrawing substituents influence reactivity and product selectivity. Various methodologies are reviewed, encompassing non-catalytic and catalytic approaches. Special attention is given to advancements in microwave-assisted techniques and high-pressure conditions, which enhance both reaction efficiency and selectivity. Additionally, the synthesis of chiral bridged bicyclic lactones from substituted 2-pyrones is examined, illustrating their versatility in organic synthesis. This review underscores the significance of IEDDA cycloaddition in pioneering new synthetic routes for building complex molecular structures.

Electrooxidative Thiocyanation of Hydroxy‐ and Alkoxybenzenes

AbstractWe developed an original method for thiocyanation of hydroxy‐ and alkoxy‐substituted benzenes (including naturally occurring compounds) using electrogenerated thiocyanogen, (SCN)₂. The presence of zinc chloride as a Lewis acid significantly enhances reaction efficiency by activating thiocyanogen. Cyclic voltammetry of the reactants and their combinations was employed to optimize reaction conditions and investigate the proposed mechanisms. This method demonstrated broad synthetic utility, leading to mono‐ and bis‐thiocyanated arenes and various heterocycles with yields 36–97 %. Notable products include the neuroprotective drug riluzole and precursors for the antiprotozoal drugs toltrazuril and ponazuril.

3D printer fabrication of boron doped Cu-MWCNT/PLA electrodes: Investigation of its efficiency in electrocatalytic hydrogen production

In this study, three-dimensional (3D) electrodes based on MWCNT-Cu/PLA with high electrocatalytic efficiency, large surface area and different amounts of nano‑boron doped MWCNT-Cu/PLA were fabricated using Fused Granular Fabrication (FGF) method with a 3D printer. When FE-SEM images are examined, MWCNT fibers and copper particles are seen more clearly on the surface due to the formation of more dense conductive networks between the conductive carbon fibers trapped in the PLA structure due to the increasing amount of boron. When XRD results are examined, it is observed that the characteristic peaks belonging to the face-centered cubic structure of Cu are dominant and the crystal size increases as MWCNT addition and boron doping increase. When Raman spectra were analyzed to investigate the internal structural changes of MWCNTs, three characteristic bands corresponding to the D band (defect), G band (graphite band) and G' band (D overtone) of MWCNTs were determined and it was observed that the ID/IG ratio decreased with increasing boron doping compared to MWCNT-Cu/PLA electrode. The B1s spectrum of the 3D 0.8B@MWCNT-Cu/PLA electrode confirmed the presence of boron with the peak corresponding to B@C bonds at 191.2 eV. The obtained 3D electrocatalysts were used as cathodes in an electrolysis cell in aqueous solution containing 1 M KOH and their catalytic efficiency in hydrogen evolution reaction (HER) was tested. In order to increase the activity of the 3D electrodes, unlike the literature, they were activated by electrochemical activation process without using organic solvent and HER measurements of the activated electrodes were performed. Before activation, the charge transfer resistance (Rct) value of the Cu/PLA electrode, which was 6219.00 Ω cm−2, decreased to 681.90 Ω cm−2 after 5 % MWCNT doping. It is seen that with boron doping, a greater decrease in Rct value is realized, reaching values of 66.50–74.56 Ω cm−2. The cathodic Tafel slopes show that the Volmer reaction is the rate-determining step for HER and the rate-determining step is the electrochemical adsorption of hydrogen on the metal surface. In addition, energy efficiency tests of the 3D electrodes in HER were also performed and electrochemically active surface areas were determined. Thus, this study has taken an important step toward using 3D electrocatalysts, which are produced with more cost and more flexible designs, unlike previous production techniques, for hydrogen energy production.

Polyoxometalate‐Derived Photocatalysts Enabling Progress in Hydrogen Evolution Reactions

AbstractPhotocatalytic water splitting is capable of converting abundant solar energy into environmentally friendly and renewable chemical energy, presenting a promising solution to alleviate the energy crisis and combat environmental pollution. The development of high‐performance photocatalysts is crucial for significantly improving the efficiency of the hydrogen evolution reaction (HER) involved. Polyoxometalate (POM)‐derived materials, known for their tunable compositions, diverse structures, electron storage/release capabilities, as well as quasi‐semiconductor photochemical properties, serve as highly efficient catalysts in sustainable photosynthesis. This comprehensive review navigates the latest advancements in the assembly strategies and HER performance of POM‐based crystalline materials. It also discusses the composite materials formed by infiltrating POM into metal‐organic frameworks (MOF) and examines the roles of transition metal compounds derived from polyoxometalates, such as sulfides and carbides, in photocatalytic HER. Emphasis is placed on the prospects for the future development of POM‐based compounds as photocatalysts, along with several strategies and outlooks that could facilitate their progress. POM‐derived materials are believed to have significant potential to enhance hydrogen production efficiency while maintaining thermal stability in HER processes.

Apparent kinetics study and efficient continuous-flow synthesis of tert-butyl hydroperoxide & tert-butyl peroxybenzoate in a microreaction system

This study advances the synthesis of tert-butyl hydroperoxide (TBHP) and tert-butyl peroxybenzoate (TBPB) using a continuous microreaction system, meticulously detailing kinetic behavior and optimization processes through over 1250 experimental data points. We have developed a platform capable of high-throughput kinetic experiments and precise reaction quenching, determining kinetic parameters and optimal conditions that significantly improve reaction efficiency and safety. Tailored microreaction strategies, including micro-mixers, plate microreactors, and micro-packed beds, were employed to manage exothermic reactions and enhance mass transfer for each peroxide. For TBHP, conditions were optimized to achieve a 99% conversion rate of tert-butanol and an 82% conversion of hydrogen peroxide, with product selectivity reaching 92%. For TBPB, under optimal conditions, benzoyl chloride conversion reached 99.5%, and TBHP conversion was 80%, with a product selectivity of 94%. The integration of the TBHP and TBPB synthesis processes into a single continuous-flow system demonstrates scalable, safe, and efficient production, highlighting significant potential for advancements in organic peroxide manufacturing.

Effect of Al and Zn on Oxygen Evolution Reaction of (FeCoNiMnCu)3O3.2

AbstractBecause of its low cost and abundant sources, hydrogen serves as a clean energy alternative capable of successfully substituting fossil fuels. A highly efficient method for generating hydrogen energy currently is by the electrolysis of water. The oxygen‐extraction reaction (OER), a component of water electrolysis, requires a complex chemical pathway that involves multiproton and multielectron interactions. To enhance reaction efficiency in the OER process, catalysts are crucial; thus, the search for high‐performance, cost‐effective catalysts is underway. This experimental study involved the enhancement of the five‐membered high‐entropy oxide (FeCoNiMnCu)3O3.2 by incorporating a sixth group element (Zn, Al). The organization, morphology, and OER properties were analyzed following the preparation utilizing a mechanical ball milling process. A series of rock salt‐type hexagonal high entropy oxides with differing ball milling durations were synthesized to investigate the influence of the production method on the surface shape and catalytic properties of high entropy oxides. The results indicated that the single‐phase rock salt structure of (FeCoNiMnCuAl)3O3.5, a high‐entropy oxide, exhibited significantly altered diffraction peaks, hence improving OER performance. Optimization of the preparation technique revealed that a 72‐h ball milling duration resulted in an overpotential of merely 293 mV and an electrochemically active surface area approximately double that of the other milling durations.

Step Towards Enzymatic Bioelectrorefinery: Design of a Ligninolytic Hybrid Air‐Breathing Biocathode

AbstractLignins, abundant aromatic biopolymers and one of the major components of lignocellulosic biomass, remain the most underutilized renewable bioresources of aromatics and hydrocarbons on the Earth. Numerous physical and chemical processes have been developed for lignin valorization; however, they generally suffer from environmentally unfriendly, harsh conditions and lack reaction specificity. On the other hand, milder methods involving biocatalysts exist but are impeded by many limitations, such as cofactor regeneration, deleterious enzyme–lignin interactions, and low stability. In this work, we attempt to eliminate the constrains encountered in enzyme‐based lignin valorization processes through the development of a novel electrochemically assisted bioprocess. This “all‐in‐one” biocathode incorporates a hybrid electrocatalytic interface combining a hydrogen peroxide‐generating passive air‐breathing gas diffusion electrode with an immobilized hydrogen peroxide‐consuming lignin peroxidase on a single surface and catalyzing the depolymerization of lignins. The ligninolytic potential of this bioelectrochemical device is demonstrated using both lignin models (veratryl alcohol and veratrylglycerol β‐guaiacyl ether) and a technical lignin at room temperature in aqueous media with the reaction efficiency of 14.9% per hour.

Advancements in LAMP-Based Diagnostics: Emerging Techniques and Applications in Viral Detection with a Focus on Herpesviruses in Transplant Patient Management.

Loop-mediated isothermal amplification (LAMP) is a highly effective molecular diagnostic technique, particularly advantageous for point-of-care (POC) settings. In recent years, LAMP has expanded to include various adaptations such as DARQ-LAMP, QUASR, FLOS-LAMP, displacement probes and molecular beacons. These methods enable multiplex detection of multiple targets in a single reaction, enhancing cost-effectiveness and diagnostic efficiency. Consequently, LAMP has gained significant traction in diagnosing diverse viruses, notably during the COVID-19 pandemic. However, its application for detecting Herpesviridae remains relatively unexplored. This group of viruses is of particular interest due to their latency and potential reactivation, crucial for immunocompromised patients, including organ and hematopoietic stem cell transplant recipients. This review highlights recent advancements in LAMP for virus diagnosis and explores current research trends and future prospects, emphasizing the detection challenges posed by Herpesviridae.

Exploring mechanistic preferences and influencing factors in acceptorless dehydrogenation reactions catalyzed by an Ir(iii)-dipyridylamine complex: A DFT study

Acceptorless dehydrogenation reactions play a pivotal role in homogeneous catalysis, with extensive applications in organic synthesis and industrial processes. Metal-ligand cooperative catalysis is crucial for enhancing reaction efficiency and selectivity. However, understanding its mechanistic pathways and identifying factors influencing catalytic performance remain challenging. In this study, density functional theory (DFT) is employed to elucidate the mechanistic selectivity of Ir(III)-bis(pyridyl)amine complexes in acceptorless dehydrogenation reactions. We specifically investigate the selectivity between pyridine nitrogen and bridging nitrogen as proton acceptor sites during the dehydrogenation process. The results indicate that the pyridine nitrogen site is preferentially chosen as the proton acceptor due to its stronger basicity and lower deformation energy. Additionally, theoretical investigations of catalytic activity across different metals in the same group reveal that early transition metals significantly influence the basicity of the pyridine nitrogen, thereby affecting catalytic activity. Our findings elucidate the unique mechanistic selectivity of bis(pyridyl)amine-based catalysts and identify critical factors influencing this selectivity, providing essential theoretical guidance for the design of more efficient catalysts in future research.

Half‐Sandwich Ruthenium Complexes With N‐Phenylpicolinamide Ligands: Preparation and Catalytic Activity in Transamidation Reaction

ABSTRACTA series of N,N‐chelate half‐sandwich ruthenium complexes based on N‐phenylpicolinamide ligands has been prepared with good yields through a facile route. These air and moisture stable N,N‐chelate half‐sandwich ruthenium complexes showed good catalytic efficiency in transamidation reactions between aromatic amines and amides under mild reaction conditions. A variety of secondary amides was obtained in high yields under open flask condition with broad substrates and good group tolerance. The excellent catalytic activity, broad substrate range, and mild reaction conditions make this catalytic system a potential candidate for industrial production. In addition, the structure of the prepared ruthenium complex has been confirmed by single crystal X‐ray diffraction.