ChemSusChem最新文献

Xylose acetalization has emerged as a potent tool to extract this sugar from lignocellulosic biomass and for creating new biobased chemicals and materials. This article elucidates a generalized reaction network for xylose acetalization and reveals the role of aldehyde electrophilicity and ring strain in intermediate formation. Aldehydes with strong electrophilicity stabilize xylose as both furanose- and pyranose-monoacetals, whereas weaker aldehydes favour xylofuranose acetalization due to the high ring strain in pyranose acetals. The energetically favoured furanose diacetals dominate the product distribution over extended reaction time regardless of aldehyde types and reaction pathways. Measurements of the xylose tautomer ratio in the reaction conditions highlighted the importance of xylose isomerization in forming furanose acetals. These mechanistic insights not only explain the evolution of reaction intermediates but also aid in identifying potential products for sustainable chemical synthesis.

Growing environmental awareness has led to a shift in focus toward green chemistry and the development of more sustainable materials. Cellulose is one of the most abundant renewable polymers, providing stability and flexibility in plant cell walls. Because of these properties, it has often been used as a base material for textiles, which can be recycled and the cellulose recovered, making it a promising candidate for environmentally friendlier polymer synthesis. Herein, we show a sustainable method for recycling and modifying cellulose to facilitate photochemical crosslinking to attain biocompatible hydrogels under mild reaction conditions, which can thus also be used for the fabrication of complex 3D structures via digital light processing (DLP). This approach presents an excellent technique for the fabrication of customized cell scaffolds for biomedical applications, such as the use as a wound dressing to treat chronic wounds.

Furfural is a promising renewable platform chemical derived from biomass. Its electrochemical conversion offers the opportunity for considerable sustainability gains, i.e., by using a combination of a renewable feedstock and renewable energy. To widen the range of products available by electrochemical conversion/derivatization, indirect electrolysis (using a redox-active mediator), is a viable way. Existing methods for indirect electrolysis of furfural have been developed for divided cells only, requiring specific membranes that increase complexity and costs. Here, we describe a convenient indirect electrochemical method of furfural oxidation in an undivided cell. In this approach, HOBr is produced in situ from bromide salt and subsequently used as an oxidant in Baeyer–Villiger-type oxidation. The initially produced product, 2(3H)-furanone, immediately hydrolyzes into succinic semialdehyde. During extraction with an organic solvent, it converts back and could be isolated from the aqueous reaction mixture in the form of 2(3H)-furanone, an unstable compound. Finally, it is isomerized into the more stable 2(5H)-furanone isomer in 48% yield. The developed method represents a simple and convenient electrochemical tool for the synthesis of a renewable furanone-based building block in an undivided cell with yields comparable to existing thermochemical methods and allows to use (renewable) electricity as a driving force.

We designed six zinc phthalocyanine derivatives (ZnPc-1–ZnPc-6) as molecular semiconductors. By adjusting peripheral substituents with differing electron-donating and -withdrawing properties (–C(CH₃)₃, –O(CH₂)CF₃, –CF₃), we rationalized solubility, energy levels, and molecular arrangement to influence interfacial charge dynamics and thus device performance. Among the derivatives, ZnPc-2 with three tert-butyl groups and a trifluoroethoxy provides favorable energy level alignment, better thin film coverage, and high conductivity suited to be used as hole-selective materials. When integrated into n–i–p architecture perovskite solar cells, it measures a power conversion efficiency approaches that of Spiro-OMeTAD under our lab conditions. ZnPc-2 showed ambient operational stability, maintaining around 80% of its initial J_MPP over 24 h without encapsulation. Our combined theoretical and experimental assessment revealed detailed electro-optical properties to substantiate the influence of molecule design on the device performance. Specifically, three tert-butyl groups with a trifluoroethoxy arm outperform, evidencing molecular design as a strategy to modulate properties.

Electrocatalytic CO₂ reduction offers a promising route to decarbonize the chemical industry by coupling renewable electricity with carbon utilization. Recent progress has achieved industrially relevant activities and selectivities, yet large-scale deployment remains hindered by challenges beyond catalyst development. System-level factors-including anodic-cathodic product pairing, reactor architectures defined by membrane choice, and electrolyte regulation-critically determine efficiency, stability, and economic viability. In this Concept, we highlight these interrelated aspects and use an automated coelectrolysis strategy that integrates CO₂ electrolysis to formate with chlorine evolution as an illustrative case. This approach underscores the importance of pairing product design with reactor engineering and electrolyte management. Together, these principles provide a framework for bridging laboratory demonstrations with sustainable and economically viable implementation of CO₂ electrolysis at scale.

An efficient, electrochemical three-component reaction for the synthesis of vinyl sulfonamides from cinnamic acids, SO₂, and amines is reported. This metal-free protocol utilizes inexpensive graphite electrodes and easy-to-use SO₂ stock solutions to facilitate a decarboxylative transformation under mild conditions. The reaction proceeds with high regio- and stereoselectivity. The use of cinnamic acid derivatives as biobased feedstocks, combined with the demonstrated scalability and electrode/electrolyte reusability, highlights the potential of this approach for a sustainable synthesis of the important vinyl sulfonamide scaffold.

Nickel Sulfides have emerged as promising electrocatalysts for alkaline hydrogen evolution reaction (HER) due to their cost-effectiveness and high catalytic activity. While growing research has focused on the initial catalyst design, less attention has been paid to structural and electrochemical modifications during prolonged HER operation. Understanding these transformations is essential for developing more active and stable nickel sulphide-based HER catalysts. This study investigated the post-HER evolution of various nickel sulphide crystalline catalysts, including NiS, NiS₂, Ni₃S₂, and Ni₃S₄, after prolonged cyclic voltammetry (CV) cycling and constant current polarization. Upon 500 CV sweeps, Raman spectroscopy confirmed structural phase transformation of all nickel Sulfides toward Ni₃S₂, i.e., the most HER-active phase, irrespective of their initial chemical composition. This electrochemical activation process led to an improvement in electrochemical surface area and charge-transfer properties. Moreover, the kinetic analysis indicated a shift in the rate-determining step from a Volmer-limited mechanism to a mixed Volmer-Heyrovsky pathway, contributing to enhanced HER kinetics. Sulfur leaching was identified as a key factor in this transformation, facilitating surface restructuring and exposure of active Ni sites to the electrolyte. Importantly, post-stability characterization confirmed that leaching occurs predominantly during initial activation and ceases thereafter, with no further structural changes over prolonged operation.

The excessive discharge of phosphorus into aquatic systems is a major environmental concern, contributing to eutrophication and biodiversity loss. This study investigates the reuse of electric arc furnace slag (EAF-slag), an abundant steelmaking byproduct, as a low-cost, upcycled adsorbent material for phosphorus removal and recovery, in line with circular economy and sustainable waste management principles. The slag, rich in calcium and reactive oxides, was extensively characterized using Raman spectroscopy, scanning electron microscopy, and X-ray fluorescence, and tested for phosphate adsorption across a wide range of concentrations (5-400 mg/L) and solid-liquid ratios (from 1:10 to 1:50 expressed as g of slag in mL of P-solution). Excellent removal efficiency was achieved under all conditions, with complete phosphate uptake and a maximum sorption capacity of 10.97 mg/g at S/L = 1:30. Post-adsorption analyses (Raman mapping, X-ray photoelectron spectroscopy, and cross-sectional energy-dispersive X-ray spectroscopy) confirmed the formation of hydroxyapatite on the slag surface. Importantly, the performance of EAF-slag was also evaluated in more complex aqueous systems containing phosphate, nitrate, and sulfate ions (50 and 100 mg/L each). The phosphate adsorption capacity remained unaffected, and the slag simultaneously removed nitrate and sulfate, confirming its multifunctional sorption behavior. Additional recycling experiments demonstrated that the spent slag can be reused after resting, maintaining satisfactory phosphorus removal efficiency (≈60%) even after 5 or 10 days. Moreover, the hydroxyapatite-enriched slag showed potential for use as a fertilizer, enabling phosphorus recovery and reuse. These findings demonstrate the potential of EAF-slag as an effective, low-cost, and sustainable material for phosphorus recovery and valorization of secondary raw materials, laying the groundwork for its future application in wastewater treatment and environmental remediation.

Zeolite Beta catalysts were explored in the benzylation of lignin-based model 4-ethylphenol to produce 2-benzyl-4-ethylphenol, an important high-density precursor for jet-fuel blending. For optimal catalytic attributes, a combined dealumination-surfactant templating was deployed to obtain Zeolite Beta, with higher Si/Al ratio (∼33-39) and integrated mesoporosity. The extent and quality of mesopores were tuned by varying CTAB quantity (0.01-0.06 M) at a fixed NH₄OH concentration (0.5 M). The enhanced templating action of CTAB micelles at higher CTAB concentrations created uniform intracrystalline mesopores of 3.5 nm. This mesopore generation was predominantly directed by healing of excess SiO^- defects associated with Al vacancies at higher CTAB concentrations as evidenced by silanol speciation study using DRIFTS. Further, ²⁷Al MAS-NMR and DRIFTS (Al-OH) revealed the loss and subsequent recovery patterns of framework Al during the dealumination and surfactant templating process, respectively. Eventually, large mesopores with a higher fraction of reinstated Brønsted acidity were generated in the CTAB-templated Beta catalysts, especially at higher CTAB concentrations (0.03 and 0.06 M). Dealuminated Beta templated with 0.06 M CTAB showed the highest benzyl alcohol conversion (∼29%), the highest selectivity for 2-benzyl-4-ethylphenol (∼42%), and the lowest dibenzyl ether selectivity (∼20%). Improved performance was attributed to its large uniform mesopores, highest Brønsted-to-Lewis acid ratio (B/L) and recovered superstrong acid sites.

Nitrosocarbonyl species (NOCs), also known as acylnitroso species, are highly reactive nitrogen-containing electrophiles. Since their first reports in the 1970s, they have shown significant synthetic potential for the preparation of aminated substrates. Their widespread adoption as versatile amination reagents began in the 2000s, driven by the development of new organometallic and organocatalytic systems. NOCs are typically generated in situ from stable precursors, such as hydroxamic acids and N-hydroxycarbamates, under oxidative conditions, in the presence of a scavenging substrate. This review highlights recent advances in NOC-based catalytic aminations over the past two decades. Specifically, their catalytic generation using oxygen, reactive oxygen species, and peroxides, followed by a subsequent capture through nitroso Diels-Alder, nitroso-ene, and nitroso-aldol reactions are comprehensively discussed. While most catalytic systems rely on Fe-, Co-, Ni-, Cu-, Mo-, Ru-, and Ir-based catalysts, emerging approaches include organocatalysis, photoredox catalysis, electrochemistry, and enzymatic systems. Sustainability and innovative process technologies are also discussed as future directions.