Publications by authors named "Joel Barrault"

The selective preparation of monoalkylglyceryl ethers (MAGEs) is a task for researchers owing to their broad range of applications. In this work, green feedstocks such as glycidol and alcohols were used to prepare MAGEs under mild reaction conditions (80 °C, 3 h, 0.5 mol % catalyst) in the presence of acid heterogeneous catalysts.

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A ferric smectite clay material was synthesized and further intercalated with Al2O3 pillars for the first time with the aim of evaluating its ability to be used as heterogeneous catalyst for the photo-Fenton decolorization of azo dye Orange II. UV irradiation was found to enhance the activity of the catalyst in the heterogeneous photo-Fenton process. Catalyst loading of 0.

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This work describes the removal of tetracycline (TC) from aqueous solution using a mesoporous alumina (meso-Al2O3) as adsorbent in the presence of ultrasonic irradiation. Adsorption of TC was investigated under various operating conditions, including pH, adsorbent dosage, ultrasound power, and initial TC concentration. The results showed that the rate of TC sorption was enhanced with the assistance of ultrasound.

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MCC Hammer: Microcrystalline cellulose (MCC) is dissolved and subsequently regenerated in a CO2 -based switchable solvent system, drastically reducing its crystallinity index and thereby its recalcitrance to hydrolysis. Among the investigated systems, based on cheap, widely available chemicals, is one capable of dissolving up to 15 wt % MCC within 1 h at room temperature. Break it down!

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The intershell spacing in different regions of a multi-walled carbon nanotube (MWCNT) was determined by analysis of high resolution transmission electron (HR-TEM) micrographs. Three general effects can be pointed out, (1) the regular intershell spacing of a CNT is bigger than that in a graphitic carbon because the curvature generates geometrical and electronic deformations which increase repulsion forces between the graphene sheets, (2) when an extra curvature appears, e.g.

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Fête DES sciences: The dehydration of fructose and inulin to HMF is conveniently performed in a cheap and sustainable choline chloride/CO(2) deep eutectic solvent (DES) system. The medium is capable of converting high contents of fructose (>100 wt %) without affecting the yield of HMF (up to 72 %). The purity of the recovered HMF is >98%, and the reaction medium can be recycled.

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Ionic liquids (ILs) can be partially substituted by glycerol or glycerol carbonate as cheap, safe, and renewably sourced co-solvents in the acid-catalyzed dehydration of fructose and inulin to 5-hydroxymethylfurfural (HMF). In the particular case of glycerol, we found that HMF can be conveniently extracted from the IL/glycerol (65:35) mixture with methylisobutylketone, limiting the reactivity of glycerol with HMF and allowing the recovery of HMF with a high purity (95 %). Influences of the fructose content, temperature, and the nature of the ionic liquid are also discussed.

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Here we report that sulfonated crystal-like benzene-silica is much more robust and active than conventionally used periodic mesoporous silica for catalyzing aqueous organic reactions.

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Glycerol is the main co-product of the vegetable oils industry (especially biodiesel). With the rapid development of oleochemistry, the production of glycerol is rapidly increasing and chemists are trying to find new applications of glycerol to encourage a better industrial development of vegetable oils. In this Review, attention is focused on the selective use of glycerol as a safe organic building block for organic chemistry.

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Coating of silica-supported sulfonic acid catalysts with hydrophobic ionic liquid leads to a significant improvement of catalyst selectivity. Many organic reactions, including Prins cyclization, cycloaddition of epoxide to aldehyde, and dehydrative etherification of secondary benzyl alcohols, proceed well in formalin or pure water. In particular, tandem dehydration/Prins cyclization reactions of tertiary and secondary alcohols with formaldehyde were developed for the first time.

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Thanks to strong hydrophilic interactions between reaction products and the catalyst surface, mesoporous silica supported sulfonic sites were found to be much more selective than homogeneous and common solid acid catalysts.

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Glycerol derivatives of cutin and suberin monomers were synthesized by acid catalysis. Their dispersion in an aqueous solution was examined by phase contrast microscopy, neutron scattering, and solid state NMR. It is shown that the phase behavior strongly depends on the nature of the derivatives forming either lumps of aggregated membranes or well dispersed membranes.

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