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Immobilized carbonic anhydrase (CA) enzyme enhances CO 2 absorption in potassium carbonate (PC) solutions, offering an attractive alternative to amine-based processes for postcombustion carbon capture. In this work, the cross-scale models of mass transfer coupled with absorption reactions were developed to evaluate the structural impacts of different enzyme immobilization supporting materials, including nonporous nanoparticle carriers (nano scale), porous microparticle carriers (micro scale), and fixed packing structures (macro scale), on the rate enhancement effect of the immobilized CA. Increasing enzyme activity was demonstrated to be an effective approach to promoting the CO 2 absorption rate; however, there was an upper limit due to the limitation of CO 2 diffusion in the liquid phase, either adjacent to the gas-liquid interface or the liquid-solid interface. The size of particle carriers is another critical factor affecting the CO 2 absorption rate. Only nanoscale particle carriers could directly enter the region within the liquid film of mass transfer, thus providing effective enzymatic enhancement. When the particle size was reduced to below 0.35 μm, the PC promoted with the immobilized CA outperformed the benchmark monoethanolamine solution. The solid-side mass transfer resistance became dominant as the particle size decreased. Modeling results also showed that using stagnant packing materials in a fixed bed as a supporting structure for CA immobilization would be impractical for accelerating CO 2 absorption.

Polyoxometalates (POMs), anionic metal-oxide clusters, are actively studied for their versatile structural designs and element selectivity. A series of Keplerate-type POMs with core-shell structures, known as POM capsules, that feature a Keggin-type POM core, has been reported. These POM capsules, with their neutral to negative charge and large molecular surface area, can serve as platforms for proton (H + ) conduction. In this study, we aimed to introduce proton carriers into the POM capsule through a proton-coupled electron transfer (PCET) reaction. It is crucial to avoid excessive reduction, as it increases electrostatic interaction between the proton and the POM capsule, hindering proton conduction. The number of incorporated electrons was varied from 0 to 11, and the POM capsule containing 3 electrons exhibited proton conductivity an order of magnitude higher than that of pristine or highly reduced POM capsules. This study serves as a proof of concept, demonstrating that PCET, combined with the core-shell structure, can effectively enhance the proton conductivity without being limited by the choice of constituent elements.

An iron-catalyzed nitrene transfer reaction for the rapid synthesis of sulfinamidines from readily available sulfenamides is reported. This method features mild conditions, short reaction times, and a broad substrate scope, allowing the preparation of a variety of sulfinamidines in good to excellent yields. The synthetic utility of the sulfinamidine products was further demonstrated through their conversion to other valuable sulfur(VI) compounds, such as sulfondiimidoyl fluorides, sulfinamidiate esters, and sulfonimidamides. Preliminary efforts in the development of an asymmetric variant showed moderate enantioselectivity.

We present a one-pot reaction that offers an efficient approach to synthesizing tetrasubstituted vinyl sulfides with high stereoselectivity. This method involves the sequential Wolff rearrangement, ylide formation, and [1,4]-aryl transfer by utilizing aryl and alkyl thiols and α-diazo carbonyl compounds as substrates. Notably, this reaction features commercially available materials, straightforward operation, atom economy, and broad substrate scope. Moreover, the primary photophysical properties (aggregation-induced emission effect) of the products were also investigated, which might be useful in functional materials via structural modification.

The present study aims to explore the potential application of proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS) for real-time monitoring of microbial volatile organic compounds (MVOCs). This investigation can be broadly divided into two parts. First, a selection of 14 MVOCs was made based on previous research that characterized the MVOC emissions of Trichoderma atroviride, which is a filamentous fungus widely used as a biocontrol agent. The analysis of gas-phase standards using PTR-ToF-MS allowed for the categorization of these 14 MVOCs into two groups: the first group primarily undergoes nondissociative proton transfer, resulting in the formation of protonated parent ions, while the second group mainly undergoes dissociative proton transfer, leading to the formation of fragment ions. In the second part of this investigation, the emission of MVOCs from samples of T. atroviride was continuously monitored over a period of five days using PTR-ToF-MS. This also included the first quantitative online analysis of 6-amyl-α-pyrone (6-PP), a key MVOC emitted by T. atroviride. The 6-PP emissions of T. atroviride cultures were characterized by a gradual increase over the first two days of cultivation, reaching a plateau-like maximum with volume mixing ratios exceeding 600 ppbv on days three and four. This was followed by a marked decrease, where the 6-PP volume mixing ratios plummeted to below 50 ppbv on day five. This observed sudden decrease in 6-PP emissions coincided with the start of sporulation of the T. atroviride cultures as well as increasing intensities of product ions associated with 1-octen-3-ol and 3-octanone, whereas both these MVOCs were previously associated with sporulation in T. atroviride. The study also presents the observations and discussion of further MVOC emissions from the T. atroviride samples and concludes with a critical assessment of the possible applications and limitations of PTR-ToF-MS for the online monitoring of MVOCs from biological samples in real time. [ABSTRACT FROM AUTHOR]

We described an iron(III) and BF 3 ·OEt 2 -promoted oxygen transfer reaction of N -aryl-α,β-unsaturated nitrones to prepare various N , O -difluoroboron β-ketoiminates in good yields ranging from 24% to 87%. Control experiments revealed that the enaminone was the vital intermediate for the formation of N , O -difluoroboron β-ketoiminates, and iron(III) combined with BF 3 ·OEt 2 played as cocatalyst to promote the oxygen transfer reaction through intramolecular cyclization and N-O bond cleavage. More importantly, an estrone-derived N , O -difluoroboron β-ketoiminate was easily prepared in 40% yield from estrone in four steps.