Reaction Conditions Research Articles

Eco-innovative synthesis of radish-derived S, N-doped carbon quantum dots via microwave irradiation for sustainable and ultra-trace fluorescent sensing of xipamide in biological fluids.

We present here a novel copper-catalyzed four-component borocarbonylative allylation of aryl olefins. Utilizing carbon monoxide as the carbonyl source under mild reaction conditions, this protocol employs readily available aryl olefins, bis(pinacolato)diboron, and allylic phosphates as the substrates to enable the simultaneous introduction of boron, carbonyl, and allyl groups.

A photoredox-catalyzed strategy enables the dual N-centered radical cascade cyclization of N-cyanamide olefins with N-sulfon/benzoylaminopyridinium salts, efficiently constructing 48 amide-decorated 2,3-fused polycyclic quinazolinones in yields of up to 86%. This metal- and base-free protocol exhibits mild reaction conditions. Moreover, they are compatible with a variety of functional groups and can accommodate a range of substrate structures. Notably, the method's practical utility is highlighted by successful gram-scale implementation and facile downstream derivatization.

To expand the availability of promiscuous oleate hydratases (OAHs) for the asymmetric hydration of unactivated alkenes via sequence-based genome mining combined with targeted amino acid substitution. From 100 screened OAHs, 13 candidates were chosen, all exhibiting hydration activity toward oleic acid. These enzymes also showed significant activity with 1-decene (2mM), with AuOAH, CkOAH, AiOAH, and CeaOAH producing (S)-2-decanol at concentrations of 822, 603, 495, and 461μM, respectively. AuOAH, CeaOAH, and CkOAH further demonstrated notable activity with short-chain 1-heptene (2mM), generating (S)-2-heptanol concentrations of 156, 115, and 133μM, respectively. AuOAH, sourced from Acinetobacter ursingii for its relatively high activity and broad substrate range, was purified and characterized, showing turnover rates of 0.43-3.21nmolmin-1mg-1 for 1-alkenes (C7-C13). The optimization of reaction conditions for whole-cell asymmetric hydration of 1-decene in recombinant E. coli (AuOAH) demonstrated that exogenous illumination with 561.5nm light (9.4µmolm-2s-1) increased 1-decene conversion by approximately 1.5-fold. Similar light-induced enhancements (1.3-2.2-fold) were observed in OAHs from various sources. Under optimized conditions, recombinant E. coli (AuOAH) achieved 13.2-78.7% conversion for various unactivated alkenes (C7-C13) in an aqueous/organic two-phase system, with ee values ≥ 98%. This study significantly enriches the enzymatic toolbox for asymmetric alkene hydration and illustrates the beneficial effect of light illumination on OAH-catalyzed hydration.

The concept of strong metal-support interaction (SMSI), a topic of investigation for over four decades, remains an important area of research in heterogeneous catalysis. While substantial progress has been made in understanding SMSI across various metal/support systems, its complexity continues to evolve. TiO2, recognized as the first support material to exhibit SMSI, has been instrumental in advancing this understanding. However, the lack of a comprehensive guide on how various factors influence SMSI on TiO2 has limited the ability to systematically control these interactions. This review seeks to provide a consolidated view of the current understanding of SMSI in TiO2-supported metal catalysts. It highlights the sensitivity of SMSI on TiO2 to a range of parameters, including pretreatment conditions and reaction environments. The dynamic nature of SMSI under reaction conditions is also explored, underscoring its complexity and potential for fine-tuning catalyst performance. Additionally, practical insights into innovative chemical methods for controlling SMSI on TiO2 are discussed, offering strategies for modulating SMSI to meet specific catalytic requirements. By addressing these aspects, this review aims to offer a valuable guide for the rational design of metal/TiO2 catalysts, ultimately contributing to a more refined and controllable approach to SMSI on TiO2.

Abstract This study investigated the catalytic transformation of methane (CH4) into methanethiol (CH3SH) over Ni catalysts supported on various metal oxides (ZrO2, TiO2, SiO2, CeO2, and γ-Al2O3), utilizing hydrogen sulfide (H2S) as a sulfur source. Among the tested catalysts, Ni/TiO2 exhibited the highest CH3SH yield, surpassing even noble-metal-supported catalysts (Pt, Pd, Ru, Rh). Optimal reaction conditions were identified using Ni/TiO2, as excessive sulfurization led to the formation of carbon disulfide (CS2) as a by-product. Density functional theory (DFT) calculations indicated that the active Ni phase was NiS, formed during the reaction, which facilitated stepwise dissociation of C–H bonds in CH4 and S–H bonds in H2S. Subsequently, CH3 species reacted with surface S–H groups to yield CH3SH. DFT analysis also revealed the C–H bond dissociation of CH4 as the rate-limiting step in this catalytic reaction.

This study introduces the preparation and tailoring of the catalytic properties of a novel biomass-based composite to produce a sustainable biolubricant, trimethylolpropane fatty acid triester (TFATE), via the transesterification of fatty acid methyl esters (FAMEs). This novel catalyst was prepared from avocado seed and chicken eggshell residues using a Taguchi experimental design to determine the best synthesis conditions. The variables tested in the catalyst preparation included CaO impregnation time and temperature, mass ratio of CaO/char, and activation temperature. The transesterification conditions to obtain TFATE were analyzed using the best eggshell-/char-based catalyst, and the reaction kinetics were measured at 120 and 150 °C. The results showed an endothermic reactive system with calculated kinetic rate constants of 7.45 × 10−3–10.31 × 10−3 L/mmol·min, and an activation energy of 15 kJ/mol. This new catalyst achieved 90% TFATE formation under optimized reaction conditions. Reuse tests indicated that catalyst deactivation occurred due to active-site poisoning, despite very low calcium leaching. Catalyst characterization confirmed the relevance of the crystalline structure and CaO loading on the avocado char surface to obtain the best catalytic properties, while 1H nuclear magnetic resonance analysis proved TFATE formation. This low-cost catalyst can be an alternative for enhancing sustainable biolubricant production with the aim of replacing petrochemical-based counterparts.

Microbial fermentation for succinic acid production has the advantages of a short production cycle, renewable raw materials, and mild reaction conditions, and is recognized as a promising green approach. However, the succinic acid fermentation process is often accompanied by by-products such as formic acid and acetic acid, which increase the cost of subsequent separation and waste resources. This study proposed a green integrated process in which Rhodotorula glutinis As2.703 was used to selectively metabolize formic acid and acetic acid in succinic acid fermentation broth to produce high-value-added single-cell protein (SCP), while succinic acid was retained. The results showed that R. glutinis As2.703 achieved a utilization rate of 100% for formic acid and acetic acid in succinic acid fermentation broth, with a biomass of 7.05g/L and a biomass yield of 0.46g/g. The protein, lipid, and carotenoid contents in SCP were 53.11%, 16.65%, and 194.15µg/g, respectively. SuperPro Designer® was used to simulate the process of producing 54,331 tons of succinic acid annually. After integrating the SCP production module, the process achieved an annual output of 11,935 tons of SCP, with an annual revenue of 19.81million USD. The operating cost for the SCP module was only 8.27million USD/year, resulting in a net annual profit of 11.54million USD. This technology not only reduced the separation cost of succinic acid but also provided a high-quality protein source for the feed industry, significantly improving the economic viability and sustainability of succinic acid production.

Self-assembling DNA crystals have emerged over the last two decades as an efficient and effective means of organizing matter at the nanoscale, but functionalization of these lattices has proved challenging as physiological buffer conditions are required to maintain structural integrity. In this manuscript, we demonstrate the silicification of mesoporous DNA crystals using sol-gel chemistry. We identify reaction conditions that produce the minimum coating thickness to confer environmental protection, and we subsequently measure this protective ability to various stressors, including heat, low ionic strength solution, organic solvents, and unprotected freezing. By soaking metal ions and dyes into the lattice after silica coating, we demonstrate that the crystals maintain their pores and that the major groove of the DNA can still be used as a sequence-specific template for chemical reactions. We image a library of different crystal motifs by electron microscopy, and we perform X-ray diffraction on these crystals, both with and without cryoprotection, to determine the structure of the DNA frame, underscoring the conserved molecular order after coating. We anticipate these mesoporous silica composites will find use in applications involving extreme, nonphysiological conditions and in experiments which utilize the DNA glass described here as a template for chemical reactions on the internal surface of architected materials.

A novel metal oxide catalyst, PdOx/CuO-ST, was prepared by calcining a Pd-embedded CuBTC precursor and compared with a PdOx/CuO-SG catalyst synthesized via a sol–gel method. Characterization results indicated that in both catalysts, Pd species were incorporated into the CuO lattice, forming synergistic interactions that lowered the reduction temperature of CuO. The PdOx/CuO-ST catalyst exhibited superior catalytic activity in the oxidative carbonylation of phenol to diphenyl carbonate when calcined at low temperature, which was attributed to well-dispersed Cu atoms and enhanced Pd–Cu integration. However, high-temperature calcination led to catalyst sintering and the formation of surface-adsorbed oxygen species, which reacted with PdO on CuO to generate inactive PdxCuyO phases, thereby reducing the active Pd2+ content and degrading catalytic performance. Under optimized reaction conditions (100 °C, 7 h, Pd/phenol molar ratio = 1/425, and 6.6 MPa), the PdOx/CuO-ST catalyst achieved a maximum phenol conversion of 79.5% and a diphenyl carbonate selectivity of 84.5%. Stability tests revealed that although the catalyst structure remained intact, deactivation occurred due to Pd leaching and the reduction in active PdO to metallic Pd0.

A solvent-dependent approach to the oxidative ring opening of cyclopropylamides with NIS under mild reaction conditions has been developed. In the presence of hexane as the solvent, 3-iodo N,O-acetal was obtained in good yields, whereas employment of CCl4 as the solvent favors the formation of 1,3-oxazines. This divergent method avoids the use of an external base, an acid, and a metal and exhibits excellent functional-group tolerance. Primary mechanistic studies revealed that halogen bonding facilitates the nucleophilic attack of 3-iodo N,O-acetal to 1,3-oxazine.

Abstract Self‐assembling DNA crystals have emerged over the last two decades as an efficient and effective means of organizing matter at the nanoscale, but functionalization of these lattices has proved challenging as physiological buffer conditions are required to maintain structural integrity. In this manuscript, we demonstrate the silicification of mesoporous DNA crystals using sol–gel chemistry. We identify reaction conditions that produce the minimum coating thickness to confer environmental protection, and we subsequently measure this protective ability to various stressors, including heat, low ionic strength solution, organic solvents, and unprotected freezing. By soaking metal ions and dyes into the lattice after silica coating, we demonstrate that the crystals maintain their pores and that the major groove of the DNA can still be used as a sequence‐specific template for chemical reactions. We image a library of different crystal motifs by electron microscopy, and we perform X‐ray diffraction on these crystals, both with and without cryoprotection, to determine the structure of the DNA frame, underscoring the conserved molecular order after coating. We anticipate these mesoporous silica composites will find use in applications involving extreme, nonphysiological conditions and in experiments which utilize the DNA glass described here as a template for chemical reactions on the internal surface of architected materials.

Herein, a comprehensive investigation is presented into the optimization of porous electrode (PE) structures in vanadium redox flow batteries (VRFBs) using topology optimization (TO) to enhance cell performance, particularly in flow‐through configurations. This work builds upon prior studies by incorporating a full cell model that accounts for species transport, electrolyte flow, charge transfer, and proton transport within both positive and negative electrodes. PEs are optimized under different depths of discharge (DoD) conditions—5%, 50%, 65%, 90% and 95%—to capture the diverse requirements for reaction kinetics and mass transport under varying reactant concentrations. The optimized structures, featuring interdigitated channels on both electrodes, yield substantial improvements in mass transport and reaction rates compared to unmodified flow‐through and interdigitated flow‐field configurations. Performance tests, including polarization curves and charge/discharge characteristics, demonstrate superior current density and electrolyte utilization in the optimized flow‐through porous electrode (OFT) designs. Among these, the OFT95% (optimized at 95% DoD) performs exceptionally well under low reactant conditions. Despite minor tradeoffs in hydraulic power loss, the optimized structures maintain competitive round‐trip efficiency, showing promise for real‐world applications. This study provides critical insights into electrode engineering for VRFBs, contributing to the advancement of sustainable energy storage technologies essential for achieving carbon neutrality.

Sodium-gallium liquid metal enables mild-condition carbon dioxide conversion to solid carbon for sustainable electrode materials.

Automated radiosynthesis of [18F]fluoromannitol on the Sofie Biosciences ELIXYS FLEX/CHEM system.

Although covalently crosslinked gelatin hydrogels have been investigated for use in 3D cell culture due to inherent bioactivity and proliferation within the denatured collagen precursor, the stability of the matrix, and relatively inexpensive synthesis, current systems lack precise control over mechanical properties, including homogeneity, stiffness, and efficient diffusion of nutrients to embedded cells. Difficulties in modifying gel matrix composition and functionalization have limited the use of covalently crosslinked gelatin hydrogels as a three-dimensional (3D) cell culture medium, lacking the ability to tailor the microenvironment for specific cell types. In addition, the currently utilized chain-growth photopolymerization mechanism for crosslinking hydrogels has a potential for side reactions between the matrix backbone and components of the cell surface, requires a high concentration of radicals for initiation, and only cures with long irradiation times, which could lead to cytotoxicity. To overcome these limitations, a superfast curing reaction mechanism, in which a thiol monomer reacts efficiently with non-homopolymerizable alkenes, is suggested. This mechanism reliably produces a well-defined matrix that does not require a high radical concentration for photoinitiation. Mechanical customization of the hydrogel is largely achievable through variation in degree of functionalization of the gelatin backbone, dependent on reaction conditions such as pH, allyl concentration, and time. This work provides a mechanistic framework for GelAGE hydrogel fabrication by elucidating the molecular mechanism of gelatin functionalization with AGE and the thiol-ene crosslinking reactions controlling network stiffness. These insights provide the foundation for engineering hydrogels that mimic the viscoelastic and structural characteristics of cartilage, enabling advanced in vitro models for osteoarthritis research.

Solvent-polarity-engineered hyaluronic acid aerogels: Synthesis of transparent nanofiber network for thermal insulation.

Potential applications of lipases rational design in the synthesis of medium- and long-chain triglycerides: Current advances and perspectives.

A synergistic microwave-assisted hydrated deep eutectic solvent (DES) pretreatment for efficient fractionation of wheat straw.

Effect of quinone concentration and pH on the structural and functional properties of bovine serum albumin-chlorogenic acid quinone covalent conjugates.