Chemistry methods : new approaches to solving problems in chemistry最新文献

A chemo-divergent Friedel–Crafts alkylation and Friedel–Crafts acylation of arenes with α-diazo ketones has been developed. In this reaction, Cu(OTf)₂ catalyzed the Friedel–Crafts alkylation via Cu-carbene intermediate, while hexafluoroisopropanol (HFIP) promoted the Friedel–Crafts acylation via the ketene intermediate. This protocol provides a controllable aromatic C(sp2)H bond functionalization of arenes by tuning the reaction conditions.

Herein, the design and validation of high-throughput experimentation reactor and modular environment for synthesis (HERMES), a 3D-printed photoreactor capable of running 24 reactions simultaneously, employing a standard reaction block and a single Kessil lamp are reported. The reactor features stirring and temperature control modules, making it an efficient tool for photochemical research in academic environments. It provides an accessible and reproducible platform for accelerating reaction discovery and optimization, while also serving as a valuable training tool in high-throughput experimentation (HTE).

Reducing atmospheric CO₂ is crucial for mitigating climate change and ensuring a sustainable future. The building sector is a major contributor, consuming 40% of global raw materials and accounting for 35% of global energy consumption. As a result, there is a growing demand for more sustainable building materials. Herein, a scalable, energy-efficient, and low-emission approach is presented to convert various waste streams into building materials via carbon mineralization and 3D printing. Calcium ions are extracted from recycled concrete using ammonium salt leaching methods and then reacted with CO₂ gas to form high-purity calcium carbonate through mineralization. This calcium carbonate is formulated into a bio-based mineral binder by incorporating kraft lignin as a rheological modifier. The binder is further combined with sawdust to produce printable inks for additive manufacturing. The resulting 3D-printed structures demonstrate robust mechanical properties and modular design potential, making them suitable for non-load-bearing building applications. By integrating CO₂ sequestration and renewable materials, this work demonstrates a closed-loop strategy for carbon capture, waste valorization, and digital fabrication, providing a new avenue for decarbonizing the built environment.

The catalytic hydrogenation of oxalic acid to glycolic acid (GA) and/or ethylene glycol (EG) has been identified as a promising route for producing value-added chemicals and potential hydrogen carriers. GA serves as a precursor for plastics and cosmetics, while EG can function as a liquid organic hydrogen carrier. In this work, an eco-friendly and scalable bottom-up approach to fabricate a Ru-based hydrogenation catalyst on θ-alumina-coated SiC foam is presented. Nitrogen doping of the MOF(Al)-based template enhances the mechanochemical stability of the resulting alumina coating by significantly modifying its surface texture and morphology. This phase-stabilization method enables higher OA conversion compared to γ-alumina and yields nearly equimolar amounts of GA and EG under continuous-flow conditions (120 °C, 50 bar). These findings demonstrate the potential of this synthesis approach for producing stabilized metal oxide phases with tailored morphologies that improve catalyst performance.

The production and widespread use of synthetic pigments and dyes have significant environmental and health impacts. Despite this, synthetic colorants remain dominant due to their wide color range, high stability, strong tinting power, and lower cost compared to natural alternatives. Therefore, to offer sustainable and competitive substitutes, eco-friendly methods for producing bio-based pigments with similar performance are essential. Herein, a methodology has been developed to extract the entire colored organic fraction occluded within seashell biomineral waste, which comprises pigments and pigment-macromolecule complexes. This process involves an optimized cleaning procedure of the biomineral soft tissues, a tailored biochemical extraction, and detailed characterization of the extracted fraction. Applied to sea urchin skeletons, this method successfully isolates polyhydroxylated naphthoquinone (PHNQ)-macromolecule complexes. These complexes show superior pH stability in purple hues compared to free PHNQ, which shifts from red to purple in basic conditions. Notably, the approach enhances colorant yield by up to five times. These results, together with mineral pigment synthesis and fabric dyeing assays performed with the extracted colored organic fraction, contribute to a better understanding of the origin of color in biominerals and reveal the versatility of these natural pigments for environmentally friendly coloring of both organic and inorganic materials.

Understanding the reactivity of hydrated electron, especially the role of solvent dynamics, remains a key challenge. Its reaction with dimethyl disulfide, a system whose known highly exothermicity contrasts with its low electron affinity, using density functional theory-based molecular dynamics simulations is investigated. This work reveals a mechanism gated by a critical S···H hydrogen bond, which enables a kinetically challenging electron transfer step. The overall exothermicity is not driven by electron transfer itself but by a large release of solvation energy that stabilizes the nascent radical anion of dimethyl disulfide. Following the electron transfer, the system undergoes a complex solvent reorganization driven by dynamic hydrogen bonding, where a relaxation of the initial hydrated electron cavity competes with the stabilization of the resulting radical anion. These findings suggest that insufficient solvation can either kinetically hinder the initial electron transfer or by subsequently failing to stabilize the anion, promote SS bond cleavage.

The Cover Feature shows a customized DRIFTS cell based on the Harrick reaction chamber for operando FTIR spectroscopic studies of plasma-assisted heterogeneous catalyzed reactions; it is connected to a mass spectrometer for online quantitative product gas analysis. The nonthermal plasma ignites in the immediate vicinity of the catalyst surface. The performance of the plasma DRIFTS cell has been demonstrated by investigating the plasma-assisted CO₂ splitting reaction with CeO₂. More information can be found in the Research Article by D. Peña Fuentes, R. Brandenburg, C. Kubis and co-workers (DOI: 10.1002/cmtd.202500057).

The Front Cover features a liquid-phase hydrogenation reactor, employing attenuated total reflectance-infrared (ATR-IR), Raman, and fluorescence spectroscopy under industrially relevant conditions. Specifically, it highlights the use of inline ATR-IR spectroscopy and partial least-squares regression to determine the concentrations of two bio-derived lactones from the acquired spectra. In the Research Article by B. M. Weckhuysen and co-workers (DOI: 10.1002/cmtd.202500054), the reactor design is clarified, and changes in the spectra not induced by concentration changes are pinpointed, shedding light on the challenges associated with performing spectroscopy under reaction conditions.

The article presents bleaching with emission and absorption monitoring (BEAM), a cost-effective and customizable optical setup designed for real-time monitoring of photochemical reactions through simultaneous measurement of absorption and emission spectra. BEAM utilizes readily available optical components such as lamp or laser diodes for excitation, cuvettes for sample containment, and spectrometers for spectral acquisition. Its modular architecture enables precise control over excitation wavelength, sample volume, temperature, and stirring conditions, making it highly adaptable to various experimental needs. The article also proposes a detailed protocol for measuring the effective photon flux density and irradiance across different optical configurations. The system's capabilities are demonstrated through the study of Citrine's photobleaching, a widely used but poorly photostable fluorescent protein (FP). BEAM enables continuous monitoring of Citrine's spectral evolution under different conditions, including excitation laser powers, solution volumes, and protein concentrations. The results revealed complex changes in both absorption and emission spectra during the bleaching process. Nevertheless, the fluorescence intensity of Citrine follows a first-order decay profile, facilitating straightforward kinetic modeling. This allowed determination of key photophysical parameters, such as the photobleaching molar cross section and quantum yield. These findings underscore BEAM's utility for characterizing fluorescent proteins and open pathways for comparative studies with other FPs.

The shift to energy-efficient near-infrared (NIR) diode lasers in polymer powder bed fusion (PBF-LB/P) challenges standard polymer powders due to insufficient NIR absorption and necessitates tailored feedstock modifications. This study explores the potential of surface modification (s-mod) of polyamide 12 (PA12) with LaB₆ nanoparticles (NP) as a scalable alternative to conventional volume modification (v-mod) with carbon black (CB). Despite a tenfold lower overall NIR absorbance, s-mod PA12 achieves comparable melting behavior with only a 1.5-fold increase in laser energy. Combined differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analyses reveal that surface-localized absorption enables partial retention of α-domains at intermediate energy densities, consistent with a heterogeneous, surface-dominated melting mechanism. At higher energies, s-mod and v-mod converge to fully γ-phase materials with comparable crystallinity. Mechanical testing demonstrates that intermediate s-mod parts exhibit higher crystallinity, whereas fully molten s-mod parts outperform v-mod counterparts in tensile strength while maintaining ductility. Our findings indicate that s-mod PA12 not only matches the processability of industrial v-mod powders but also introduces new degrees of freedom for tailoring mechanical properties via controlled melting. Decoupling energy absorption from volumetric filler loading expands the material design space for NIR-based additive manufacturing and paving the way for next-generation, high-performance polymer components.