Efficient adsorptive separation of propylene/propane (C 3 H 6 /C 3 H 8 )i sh ighly desired and challenging.K nown strategies focus on either the thermodynamic or the kinetic mechanism. Here,w er eport an interesting reactivity of am etal-organic framework that improves thermodynamic and kinetic adsorption selectivity simultaneously.W hen the metal-organic framework is heated under oxygen flow, half of the soft methylene bridges of the organic ligands are selectively oxidized to form the more polar and rigid carbonyl bridges. Mixture breakthrough experiments showed drastic increase of C 3 H 6 /C 3 H 8 selectivity from 1.5 to 15. Forc omparison, the C 3 H 6 /C 3 H 8 selectivities of the best-performing metal-organic frameworks Co-MOF-74 and KAUST-7 were experimentally determined to be 6.5 and 12, respectively.G as adsorption isotherms/kinetics,s ingle-crystal X-ray diffraction, and computational simulations revealed that the oxidation gives additional guest recognition sites,w hich improve thermodynamic selectivity,a nd reduces the framework flexibility,w hich generate kinetic selectivity.
For straightforward access to various substituted 1,1-diarylalkanes a photoredox-catalyzed and copper-promoted 1,2-alkylarylation reaction of styrenes has been developed, which uses α-carbonyl alkyl bromides and N,N-disubstituted anilines as functionalization reagents.
The functionalization of unactivated C(sp3)─H bonds represents one of the most powerful and most atom-economical tools for the formation of new carbon-based chemical bonds in synthesis. Although cross-dehydrogenative coupling reactions of two distinct C─H bonds for the formation of carbon-carbon bonds have been well investigated, controlled functionalizations of two or more different C(sp3)─H bonds across a functional group or a molecule (e.g., an alkene or alkyne) in a single reaction remain challenging. Here, we present a three-component dialkylation of alkenes with common alkanes and 1,3-dicarbonyl compounds via synergistic photoredox catalysis and iron catalysis for the synthesis of two functionalized 1,3-dicarbonyl compounds. Mechanistic studies suggest that the photoredox catalysis serves as a promotion system to allow the dialkylation to proceed under mild conditions by reducing the oxidation and reduction potentials of the iron intermediates and the reaction partners.
Photolithography is one of the most commonly used techniques in semiconductor manufacturing, which is the foundation for all the modern electronic device fabrication. However, deep and extreme ultraviolet lithographic systems as well as the corresponding photomasks are both relatively expensive. The fabrication methods are based on the low‐speed high‐cost electron‐beam lithography or focused‐ion‐beam etching. Therefore, a maskless high‐speed method is highly recommended for the micro/nano‐structure fabrication. Among all these maskless methods, direct laser writing (DLW) is an important and widely adopted micro‐processing technique. Based on the nonlinear exposure, the feature size can achieve down to tens of nanometers. However, the speed of DLW is a technical bottleneck. To overcome this issue, parallel DLW methods are developed, including the self‐assembly microspheres laser patterning, laser interference lithography, and multifocal array DLW. Herein, the principles, advantages, challenges, and applications of these parallel processing technologies are summarized. Nanoscale resolution for large area arbitrary periodic pattern fabrication is achieved. Meanwhile, these technologies have the unique ability to build 3D structures instead of conventional 2D patterns, which is the direction of future micro/nano‐fabrication. These techniques are widely applied to surface processing and functional device fabrication in the field of sensing, solar cells, and metamaterials.
Cyclohexanone was chosen as a model substrate to evaluate certain catalysts for the hydrodeoxygenation of aliphatic ketones in a fixed‐bed reactor. The experimental results indicated that alkali‐treated Ni/HZSM‐5 exhibited excellent performance for this reaction. Two aspects of the catalyst are enhanced by alkaline treatment; the amount of strong acid sites on the catalyst is sharply reduced, and also a large number of mesopores are generated in the catalyst. The decrease of strong acid sites suppresses the formation of low‐boiling products and aldol‐condensation side products, while the mesopores improved hydrogenation and dehydration performances of the catalyst. These two aspects also promoted the catalyst’s excellent time‐on‐stream performance. Additionally, generality of the catalyst is proved; most of the selected carbonyl compounds can be hydrodeoxygenated to the corresponding alkanes with selectivities of more than 97.0 %.
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