In this article, we review the recent progress that has been made in the field of Lewis-acid catalysis of carbon carbon-bond-forming reactions in aqueous solution. Since water hampers the hard hard interactions between the catalyst and the reactant, it often complicates catalysis. However, once coordination has taken place, water can have beneficial effects on rates and selectivities of Lewis acid catalysed Diels Alder reactions, aldol reactions, allylation reactions, Barbier and Mannich type reactions as well as Michael additions.
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Michael additions of α-nitroesters with enones and α,β-unsaturated aldehydes result in quantitative conversions to the corresponding 1,4-adducts by performing the reactions in water in the presence of ytterbium triflate as water-tolerant Lewis acid.
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The need of an adaptive sustainable solution for the increased land scarcity, growing urbanization, climate change and flood risks resulted in the concept of the floating urbanization. In The Netherlands this new type of housing attracted the interest of local authorities, municipalities and water boards. Moreover, plans to incorporate floating houses in the urban planning have already been developed. However, the knowledge gap regarding the potential effect on the water quality halts the further development of the floating houses. This paper shows the results of a water quality measurement campaign, as part of the national program “Knowledge for climate”, at a small floating houses project in Delft and serves as a case study for addressing the environmental-ecological knowledge gap on this topic.
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Due to the existing pressure for a more rational use of the water, many public managers and industries have to re-think/adapt their processes towards a more circular approach. Such pressure is even more critical in the Rio Doce region, Minas Gerais, due to the large environmental accident occurred in 2015. Cenibra (pulp mill) is an example of such industries due to the fact that it is situated in the river basin and that it has a water demanding process. The current proposal is meant as an academic and engineering study to propose possible solutions to decrease the total water consumption of the mill and, thus, decrease the total stress on the Rio Doce basin. The work will be divided in three working packages, namely: (i) evaluation (modelling) of the mill process and water balance (ii) application and operation of a pilot scale wastewater treatment plant (iii) analysis of the impacts caused by the improvement of the process. The second work package will also be conducted (in parallel) with a lab scale setup in The Netherlands to allow fast adjustments and broaden evaluation of the setup/process performance. The actions will focus on reducing the mill total water consumption in 20%.
The World Health Organization has pinpointed antimicrobial resistance (AMR) of increasing global concern, causing increased healthcare costs and threatening human health. Although AMR is a naturally occurring process, it is accelerated by misuse/overuse of antibiotics. Additionally, the development and production of antibiotics is becoming increasingly challenging and costly. These challenges underline the high demand for alternative microbial inhibitors (e.g. antibiotics) and their development. The chemical compound Allicin has been studied for its potential health benefits, including antimicrobial properties[1,2] and potential cardiovascular benefits[3]. It has been suggested that the antimicrobial effect of Allicin could be achieved indirectly by the imprint it leaves in surrounding water molecules, i.e. its hydration shell. Such imprints are known as time-crystals and possess unique properties. Since often biochemical reactions occur via water molecules and their hydrogen bonds, it is possible that a time-crystal imprint of a substance in water might have a similar effect as the substance itself, e.g. antimicrobial inhibition. A consortium of universities, knowledge institutes and companies was formed to test this hypothesis based on the antibacterial properties of Allicin, resulting in the project HyTimeCIA. The experiments involve attaching allicin onto a polymer surface (i.e. hybridization), thereby providing antibacterial properties. This surface is then exposed to bacteria to test the antimicrobial properties of the allicin/polymer surface. If proven feasible, HyTimeCIA could provide a novel alternative microbial inhibitor fixated to a surface, allowing for localized application of antibacterial effects and potentially reducing the requirement of antibiotics. This not only mitigates AMR, but also facilitates production of microbial inhibitors that are particularly difficult or expensive. From the partners perspective, HyTimeCIA provides opportunities for chemical-free alternative antimicrobial (water)treatment technology and gained knowledge on alternative microbial inhibitors, both aspects which are highly in demand due to AMR and antibiotic production challenges.
