High Throughput Approach Applied to VOC Oxidation at Low Temperature Approche haut débit appliquée à l’oxydation basse température des COV

A High Throughput (HT) approach is used to prepare and characterize the catalytic activity of materials for the destruction of Volatile Organic Compounds (VOC) at low temperature. The interest of the Designs of Experiments (DoE) in the primary screening is demonstrated through modeling catalysts composition according to the light-off temperature detected by infrared thermography. The combination of the mass spectrometry and the infrared thermography appears very useful to confirm and increase information about catalytic properties of the catalysts extracted to the primary screening stage. Finally, in situ Raman spectroscopy with infrared thermography allows to better understand the origin of the catalytic properties in the case ofAu/CeO2 catalysts. A strong interaction between gold and Ce-O bonds leading to an improvement of the cerium oxide reducibility could explain its high reactivity for 2-propanol oxidation at lower temperature. Une approche haut debit (HD) est utilisée de la préparation jusqu’à la caractérisation de l’activité catalytique des matériaux pour l’élimination des Composés Organiques Volatils (COV) à basse température. L’intérêt des plans d’expériences (DoE, en anglais Designs of Experiments) dans le screening primaire est démontré grâce à l’identification d’une composition optimale de catalyseur prédite à l’aide des différentes températures d’ignition des catalyseurs obtenues par thermographie infrarouge. La combinaison in situ de la spectrométrie de masse et de la thermographie infrarouge s’est avérée d’une grande utilité pour confirmer et augmenter le niveau d’information concernant les propriétés catalytiques des catalyseurs provenant du screening primaire. Enfin, la spectroscopie Raman in situ couplée à la thermographie infrarouge permet de mieux comprendre l’origine des propriétés catalytiques dans le cas du catalyseur Au/CeO2. Une forte interaction entre les particules d’or et des liaisons Ce-O, impliquant une augmentation de la réductibilité de l’oxyde de cérium, pourrait expliquer son importante réactivité vis-à-vis de l’oxydation de l’isopropanol à plus basse température

Bifunctional mannoside-glucosinolate glycoconjugates as enzymatically triggered isothiocyanates and FimH ligands

International audienceGlucosinolates are sulfur-containing secondary metabolites found in plants of the Brassicale order. They are precursors of isothiocyanate species, resulting from C–S hydrolysis catalysed by the thioglucohydrolase myrosinase. We describe the synthesis of bifunctional glucosinolate–mannoside glycoconjugates combining both the structural features of a substrate of myrosinase and a ligand of the lectin FimH. We show that these glycoconjugates serve as enzyme substrates and that myrosinase can indeed hydrolyze the glucosinolate moiety with affinities (KM, Vmax) comparable to the natural substrates glucomoringin and sinigrin. This enzymatic hydrolysis of the thioglycosidic bond led to the efficient formation of an isothiocyanate which was assessed by the formation of the corresponding dithiocarbamate derivatives. Finally, we show that our synthetic bifunctional glycoconjugates also serve as FimH ligands where the glucosinolate moiety does not hamper the interaction with the lectin. Our findings set the stage for an original bioconjugation tool, allowing for myrosinase-triggered specific labelling of lectins using glucosinolate glycoconjugates as non-toxic, water soluble isothiocyanate precursors

The use of styrene-butadiene rubber waste as a potential filler in nitrile rubber: order of addition and size of waste particles

Styrene-butadiene rubber (SBR) has large applications in the shoe industry, especially as expanded sheets used to produce insoles and inner soles. According to TG analysis, the rubber content in SBR residues (SBR-r) was found to be around 26-wt%. Based on that data, a cost-effective technique for the reuse of SBR-r in Nitrile rubber (NBR) was developed. Later, the effect of SBR-r on the cure behavior, mechanical performance, swelling, and crosslink density of reused rubber was investigated, with more emphasis placed on the effect of both particle size and loading of waste filler. Cure characteristics such as optimum cure time and scorch time were then reduced by the increasing amount of SBR-r filler. Owing to the reinforced nature of the largest particle size SBR-r, the best results for the mechanical properties of NBR were those in which SBR-r was added at the end of the cure process. The study has thus shown that SBR residue (SBR-r) can be used as an economical alternative filler in NBR