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Chemical Recycling of Polymethacrylates
Full text linkPolymethacrylates, including poly(methyl methacrylate) (PMMA), are produced on a large scale for applications ranging from optics to construction, yet their end-of-life fate remains largely linear. Chemical recycling to regenerate the monomer (depolymerization) offers a promising route to circularity, but conventional methods such as pyrolysis rely on high-temperature random scission pathways that suffer from poor selectivity and undesirable side reactions. Recent advances have demonstrated that polymethacrylates synthesized by controlled radical polymerizations can undergo efficient depolymerization under milder conditions through reactivation of thermally labile chain-end functionalities. Emerging mid-chain-initiated depolymerization strategies further extend low temperature chemical recycling to polymers produced by conventional free-radical polymerization. This review highlights these developments, comparing mechanisms, limitations, and opportunities towards scalable, energy-efficient chemical recycling of polymethacrylates to support a more sustainable plastic economy
Overcoming Hydrogen Losses in Fuel Cells: A Membrane-based Approach to Sustainable Energy
Full text linkHydrogen (H2) is increasingly recognized as a key candidate to replace fossil fuels due to its high energy density, zero-carbon combustion, and compatibility with fuel cell technologies. Fuel cells offer an efficient means to convert hydrogen into electricity, with only water as a byproduct, making them a cornerstone for the energy transition. However, challenges remain in the widespread adoption of hydrogen, including production methods (green, blue, and grey hydrogen), transportation, and associated losses during fuel cell operation. A critical issue is hydrogen purge losses, where unreacted H2 is vented to maintain fuel cell efficiency and durability. This article explores the fundamentals of H2 fuel cells, purge losses, and the environmental implications. Potential solutions are examined, such as catalytic burning and recirculation systems, to minimize the hydrogen losses in fuel cell strategies. An innovative hydrogen recovery membrane, the SEPARATIC-H2, developed at the University of Fribourg, has been showcased to enhance fuel cell efficiency while reducing H2 waste. By addressing these challenges, hydrogen can reach its potential, accelerating the transition toward a sustainable, low-carbon future
Functionalization of Quinones by Green Methods
Full text linkQuinone motifs play a crucial role in a wide range of living organisms, including bacteria, fungi, higher plants, and some animals. They are also present in numerous natural pigments. This review summarizes recent advances in the direct functionalization of quinones using green methods. Green synthesis of quinones employs environmentally sustainable strategies such as solvent-free microwave-assisted techniques, photoredox catalysis, and electrochemical oxidation, etc. These approaches aim to minimize hazardous waste generation and energy consumption, offering a cleaner alternative to conventional synthetic methods
The Best Practices Series from the EFMC is a Wonderful Educational Resource for the Chemical Biology and Medicinal Chemistry Communities
Full text linkThe European Federation for Medicinal Chemistry and Chemical Biology (EFMC) curates an open-access resource for the medicinal chemistry community known as the ‘Best Practices’ series. The series content is created by volunteers across the EFMC community. Although the series is growing in popularity, it is still a relatively unknown gem for our community. This highlight article aims to bring the message to the Swiss Chem Bio and Med Chem community that such a resource exists and brings value to our members
Alkali Metal Complexes for the Controlled Synthesis of Bioplastics: Tuning the Metal Environment and the Reaction Conditions
Full text linkPolylactide (PLA) is one of the most prominent bioplastics, derived from renewable feedstocks and noted for its biocompatibility. Yet, the full potential of PLA has not been fulfilled due to limitations in its production processes, especially the dependence on traditional toxic catalysts such as tin(II) octanoate. Recent studies have highlighted the advantages of alkali metal complexes as efficient, non-toxic, and versatile catalysts for the ring-opening polymerization (ROP) of lactide. Historically, alkali metals were considered too reactive or poorly controlled to be effective in ROP catalysis. However, recently it has been demonstrated that this limitation can be overcome through judicious ligand design and reaction engineering, transforming alkali metals into powerful tools for sustainable polymer chemistry. As such, the use of bulky ligands can tune the metal environment and assert a better control over the polymerization. As well, depending on the presence or not of the co-initiator, the polymerization mechanism varies significantly which influences the control of the stereoregularity of the polymers obtained, and poly-L-lactide (PLLA) with different D-lactide units can be obtained. This stereoregularity determines the thermal and mechanical properties and hence the applications of the PLLA. Furthermore, using chiral alkali compounds and controlling the aggregation, isoselective rac-lactide polymerization can be achieved. Hence, catalyst design and reaction conditions can be combined to tune polymer microstructure, molecular weight, and tacticity, advancing PLA toward a sustainable and circular material future. Furthermore, the alkali metal compounds described herein not only enable rapid lactide polymerization, but also promote PLA depolymerization under mild conditions, thereby connecting synthesis with chemical recycling
Assessing Coordination of Organic π-Acceptors to Alkali-Metal Nickelates
Full text linkNickel olefin complexes have served as ubiquitous precursors in nickel chemistry ever since their discovery. One class of compounds derived from these precursors is low valent nickelate complexes. While their role as key intermediates in challenging cross-coupling reactions has recently been confirmed, knowledge regarding the coordination preferences of these complexes, in particular when extended to π-systems, is still very limited. Herein we present a summary of our most important findings from the investigation of the coordination of a series of organic π-acceptors to low valent alkali-metal nickelate complexes. This includes the coordination of polyaromatic molecules such as anthracene or coronene. Extending these studies to biphenylene has uncovered the ability of these heterobimetallic complexes to mediate C–C bond oxidative addition processes, where the nature of the alkali-metal plays an important role in influencing the rate of these activations
