Publications by authors named "Chretien Simons"

MeClas is a web-based tool to generate (eco)toxicity hazard categories and corresponding classification & labelling information of inorganic metal-containing complex materials such as ores, concentrates, intermediates or alloys for which the manual application of the GHS/CLP rules is very complex and requires a high level of consistency. The tool comprises several tiers, aimed at the progressive refinement of classification through recognition of specific mineral content, speciation/mineralogy up to bio-availability corrections. Where relevant in a regional jurisdiction (EU and US), mandatory classification references are used complementary to high quality (eco)toxicity reference values (ERV/TRV) and self-classifications.

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Article Synopsis
  • The article details a new method for recycling a hydroformylation catalyst using selective adsorption to custom-designed supports after the reaction.
  • The catalyst separation relies on non-covalent interactions between a ligand and the support, allowing the active catalyst to be released for reuse by changing the solvent.
  • A specific rhodium pre-catalyst shows high stability and efficiency, achieving a turnover number of 170,000, with successful recycling demonstrated through multiple runs using end-capped silica-alumina supports.
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Rhodium-MonoPhos was successfully immobilised by ionic interactions on aluminosilicate AlTUD-1. The resulting new heterogeneous catalyst can be used in water and showed excellent enantioselectivity and activity in the asymmetric hydrogenation of methyl-2-acetamidoacrylate.

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A new Brønsted acidic aluminosilicate, AlTUD-1, with ideal characteristics for catalyst immobilisation (mesoporous structure, high surface area, and high Al(tetrahedral)/Si ratio), was used successfully for the noncovalent anchoring of two well-established asymmetric hydrogenation catalysts: [Rh(I)(cod)[(R,R)-MeDuPHOS]]BF4 (1) and [Rh(I)(cod)[(S,S)-DiPAMP]]BF4 (2). The new heterogeneous catalysts, 1-AlTUD-1 and 2-AlTUD-1, prepared by a straightforward ion-exchange procedure, were highly active and selective in the asymmetric reduction of dimethyl itaconate (3) and methyl 2-acetamidoacrylate (4), giving enantiomeric excesses of up to >98%. The catalysts showed similar behaviour to their homogeneous counterparts.

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