Ewoud

This study examines the potential of a miniaturized solvent extraction plant (MSXP) to improve the efficiency and reproducibility of laboratory and pilot-scale metallurgical studies that typically require extended testing periods. The MSXP has been designed to replace conventional solvent extraction (SX) apparatus and aims to reduce start-up time, time to reach equilibrium, and overall test time. Two copper solvent extraction (Cu-SX) research campaigns were conducted to test the functionality, ease of operation, modularity, and reproducibility of the MSXP. The first campaign quantified the extraction efficiency and net copper transfer, while the second campaign operated the MSXP in a semi-continuous countercurrent flow configuration with three extraction and two stripping stages. The main variables studied in the first campaign are the number of stages (1─3), volumetric flow rates (O/A, 1─3), and organic phase residence time in the micro-contactor (0.7─2.4). The results demonstrate that the MSXP can work with very low stage efficiencies (48%), while achieving high copper recoveries (>90%). At the stripping circuit level, we show that the MSXP can operate at superior stage efficiencies (> 100%), with low copper recoveries (30─55%). The reproducibility evaluation also demonstrates high statistical confidence (<6% CV) in the obtained process values. The MSXP offers great flexibility in net copper transfer and can be used to benchmark and emulate a wide range of Cu-SX systems. Experimental Cu-SX campaigns can be run in about 60 minutes, while investing roughly US$1.4/h on reagents, which is significantly lower compared to typical campaigns that can last from days to weeks to reach reliable research outcomes and require about US$62/h for reagents. The potential of MSXP extends to more elaborate solvent extraction systems, specifically those designed to purify energy-critical elements like lithium, nickel, cobalt, or rare-earth elements. This study demonstrates the promise of process intensification approaches for improving the efficiency of laboratory and pilot-scale SX studies, which can help in reducing time, reagent, and energy consumption while improving the reproducibility of results.

Perylene diimides (PDI) have an extraordinary ability to activate both energy and electron transfer process upon light excitation, however, their extremely low solubility has hindered their wide use as photocatalysts. Here, we show a series of supports developed to anchor PDI and to enable its use as a heterogeneous photocatalyst in diverse reactor set-ups. Inert, easy-to-handle, glass microspheres of various morphological and chemical properties were chemically functionalised with PDI to form an inorganic-organic hybrid material. Using the photo-oxidation of n-butyl sulfide as a benchmark reaction for the synthesis of sulfoxides, we show that immobilised PDI are highly active, outperforming reported homogeneous photosensitisers, and capable of reuse in both batch and flow reactors. Transferring the process from batch to flow resulted in a 10-fold reduction in irradiation time and an increase in the space-time-yield by a factor of 10 (0.04 vs 0.38 mmol-1 h-1 mL-1 batch vs flow). This work combines the remarkable photocatalytic properties of PDI with inert, easy to handle glass beads, producing hybrid materials that are reusable and can be adapted for performing heterogeneous photocatalysis in a range of scalable photochemical reactors.

Nature, Published online: 27 June 2023; doi:10.1038/d41586-023-02091-w

Tests show that certain types of plasticware give off high levels of microscopic plastic particles when heated in an microwave oven.

Proceedings of the National Academy of Sciences, Volume 120, Issue 25, June 2023.

This work demonstrates a hydrogen-transfer reductive catalytic fractionation of lignocellulose. By incorporating a hydrogen bond acceptor of choline chloride, high yields of aromatic monomers with switchable selectivity are achieved. Choline chloride greatly improves lignin dissolution and tailors the hydrogenolysis of lignin. The proposed strategy promotes the development of targeted lignin valorization and lignin-first biorefinery.

Abstract

Lignin solubilization and in situ hydrogenolysis are crucial for reductive catalytic fractionation (RCF) of lignocellulose to aromatic monomers. In this study, we reported a typical hydrogen bond acceptor of choline chloride (ChCl) to tailor the hydrogen-donating environment of the Ru/C-catalyzed hydrogen-transfer RCF of lignocellulose. The ChCl-tailored hydrogen-transfer RCF of lignocellulose was conducted under mild temperature and low-pressure (<1 bar) conditions, which was applicable to other lignocellulosic biomass sources. We obtained an approximate theoretical yield of propylphenol monomer of 59.2 wt % and selectivity of 97.3 % using an optimal content of ChCl (10 wt %) in ethylene glycol at 190 °C for 8 h. When the content of ChCl in ethylene glycol was increased to 110 wt %, the selectivity of propylphenol switched toward propylenephenol (yield of 36.2 wt % and selectivity of 87.6 %). The findings in this work provide valuable information for transforming lignin from lignocellulose into value-added products.

Synthesis
DOI: 10.1055/a-2014-3203

Described herein is an iodide-promoted insertion reaction of vinyltrimethylsilane into diaryl or dialkyl disulfides in the presence of iodine/KF leading to the production of a 1,1′-adduct, a dithioacetal derivative. This method also accomplishes insertion into a diaryl diselenide to afford the corresponding diselenoacetal derivative.
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Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany

Article in Thieme eJournals:
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Nature Synthesis, Published online: 06 February 2023; doi:10.1038/s44160-022-00223-0

The incorporation of multiple carbon labels into drug candidates is a difficult synthetic challenge. Here an operationally simple method for the preparation of multi-carbon-labelled isotopologues of active pharmaceutical ingredients and other bioactive molecules, through a combined catalytic three-gas surrogate hydroformylation strategy, is reported.