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- ItemScalable synthesis and polymerisation of a β-angelica lactone derived monomer(Cambridge : RSC, 2020) Dell'Acqua, Andrea; Stadler, Bernhard M.; Kirchhecker, Sarah; Tin, Sergey; de Vries, Johannes G.Bio-based levulinic acid is easily ring-closed to α-angelica lactone (α-AL). α-AL can be isomerized to the conjugated β-AL under the influence of base, but since this is an equilibrium mixture it is very hard to devise a scalable process that would give pure β-AL. This problem was circumvented by distilling the equilibrium mixture to obtain a 90 : 10 mixture of β-and α-AL in 88% yield. This mixture was used for Diels-Alder reactions on 3 terpenes and on cyclopentadiene in up to 100 g scale. The latter DA adduct was subjected to a ROMP reaction catalysed by the Grubbs II catalyst. The resulting polymer has some similarities to poly-norbornene but is more polar. The polymer can be processed into films with very good transparency. © The Royal Society of Chemistry.
- ItemFacile and scalable synthesis of sub-micrometer electrolyte particles for solid acid fuel cells(London : RSC Publishing, 2018) Lohmann-Richters, F.P.; Odenwald, C.; Kickelbick, G.; Abel, B.; Varga, Á.Nanostructuring fuel cell electrodes is a viable pathway to reach high performance with low catalyst loadings. Thus, in solid acid fuel cells, small CsH2PO4 electrolyte particles are needed for the composite powder electrodes as well as for thin electrolyte membranes. Previous efforts have resulted in significant improvements in performance when using sub-micrometer CsH2PO4 particles, but laborious methods with low throughput were employed for their synthesis. In this work, we present a simple, robust, and scalable method to synthesize CsH2PO4 particles with diameters down to below 200 nm. The method involves precipitating CsH2PO4 by mixing precursor solutions in alcohol in the presence of a dispersing additive. The influence of the concentrations, the batch size, the solvent, and the mixing process is investigated. The particle size decreases down to 119 nm with increasing amount of dispersing additive. Mixing in a microreactor leads to a narrower particle size distribution. The particle shape can be tuned by varying the solvent. The ionic conductivity under solid acid fuel cell conditions is 2.0 × 10-2 S cm-1 and thus close to that of CsH2PO4 without dispersing additive.