Laurent Bonneviot
École normale supérieure de Lyon
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Publication
Featured researches published by Laurent Bonneviot.
Journal of the American Chemical Society | 2013
Kun Zhang; Langlang Xu; Jingang Jiang; Nathalie Calin; Koon-Fung Lam; Sanjun Zhang; Haihong Wu; Guangdong Wu; Belén Albela; Laurent Bonneviot; Peng Wu
Mesoporous silica nanoparticles (MSNs) are experiencing rapid development in the biomedical field for imaging and for use in heterogeneous catalysis. Although the synthesis of MSNs with various morphologies and particle sizes has been reported, synthesis of a pore network with monodispersion control below 200 nm is still challenging. We achieved this goal using mild conditions. The reaction occurred at atmospheric pressure with a templating sol-gel technique using cetyltrimethylammonium (CTA(+)) as the templating surfactant and small organic amines (SOAs) as the mineralizing agent. Production of small pore sizes was performed for the first time, using pure and redispersible monodispersed porous nanophases with either stellate (ST) or raspberry-like (RB) channel morphologies. Tosylate (Tos(-)) counterions favored ST and bromide (Br(-)) RB morphologies at ultralow SOA concentrations. Both anions yielded a worm-like (WO) morphology at high SOA concentrations. A three-step formation mechanism based on self-assembly and ion competition at the electrical palisade of micelles is proposed. Facile recovery and redispersion using specific SOAs allowed a high yield production at the kilogram scale. This novel technique has practical applications in industry.
Journal of the American Chemical Society | 2014
Wen-Juan Zhou; Lin Fang; Zhaoyu Fan; Belén Albela; Laurent Bonneviot; Floryan De Campo; Marc Pera-Titus; Jean-Marc Clacens
Stabilization of oil/oil Pickering emulsions using robust and recyclable catalytic amphiphilic silica nanoparticles bearing alkyl and propylsulfonic acid groups allows fast and efficient solvent-free acetalization of immiscible long-chain fatty aldehydes with ethylene glycol.
Microporous and Mesoporous Materials | 2001
Ch Danumah; Sébastien Vaudreuil; Laurent Bonneviot; Mosto Bousmina; Suzanne Giasson
Abstract Dual templating using aqueous cetyltrimethylammonium chloride/hydroxide (CTMA Cl/OH) and latex spheres was performed to prepare powders of bimodal silica molecular sieves with mesopore and macropore systems. The CTMA/Si ratio was chosen to generate a cubic mesopore of MCM-48 structure. According to high Brunauer–Emmett–Teller surface area, narrow pore size distribution, X-ray diffraction powder pattern and scanning electron micrographs, the cubic mesophase is located within the macropore walls, which is the characteristic of a hierarchical porous system.
Studies in Surface Science and Catalysis | 1996
L. Le Noc; D. Trong On; S. Solomykina; Bousselham Echchahed; François Béland; C. Cartier dit Moulin; Laurent Bonneviot
The quantification of the extra-framework titanium species in titanium silicalites of MFI structure, TS-1, was performed using either XANES at the Ti K-edge or XPS Ti (2p) photolines. In addition, two different framework sites, [Ti(OH)(OSi)3] and [Ti(OSi)4], were characterized in dehydrated samples using Diffuse Reflectance UV-visible, multiple scattering analysis of EXAFS, 1H and 29Si NMR spectroscopies.
RSC Advances | 2012
Hodna Kassab; Mahmoud Maksoud; Sonia Aguado; Marc Pera-Titus; Belén Albela; Laurent Bonneviot
Polyethylenimine (PEI) has been grafted on a 2D hexagonal mesostructured porous silica of MCM-41 type (LUS silica) using 3-glycidoxypropyltrimethoxysilane (GTMS) as a grafting agent to develop sorbents for CO2 capture. The advantage of this tether is to create ethanolamine units upon reaction of the epoxy group with the amine functions of PEI. Two synthetic routes have been explored: (1) reaction of GTMS and PEI and then grafting on a calcined MCM-41 silica (M-1), and (2) grafting of GTMS on the silica and then reaction with PEI (M-2). In both cases, the grafted solids are well structured according to the XRD patterns. The amounts of glycidoxypropylsilane (GS) and PEI are 14 and 9 wt%, and 21 and 16 wt%, respectively, for samples M-1 and M-2. The CO2 adsorption capacity of both materials has been tested at 303 K and 101 kPa and compared to a bare LUS silica sample impregnated with 25 wt% PEI (M-3-25). Samples M-1 and M-2 containing ethanolamine groups show higher CO2 adsorption capacities, with loading of about 150 and 134 mgCO2 / gPEI (36 and 43 mgCO2 / g-sorbent), respectively, while the CO2 adsorption capacity was about 55 mgCO2 / gPEI (14 mgCO2 / g-sorbent) for the impregnated solid M-3-25.
New Journal of Chemistry | 2009
Sébastien Abry; Aurore Thibon; Belén Albela; P. Delichère; Frédéric Banse; Laurent Bonneviot
A bio-inspired synthesis of a silica grafted polydentate copper(II) complex is developed following the structural concept of metalloproteins where well defined metal ion coordination state, hydrophobic environment and confined space are present. Mesostructured porous silica of MCM-41 type replaces the proteic matrix while the pore surface is engineered according to a molecular stencil patterning technique combining both partial hydrophobization and site isolation in order to mimic the enzymatic cavity. The overall five-step synthesis includes the sol–gel formation of the silica matrix followed by partial removal of the structure directing agent and, sequential surface chemical modifications. This new methodology is illustrated here using trimethylsilyl functions to dilute bromopropylsilyl tripod tethers that undergo, directly in the pores, in a subsequent step nucleophilic substitution by a tetradentate ligand N,N′-bis(2-pyridinylmethyl)ethane-1,2-diamine (L42). The metallation of the grafted ligand is obtained in the final step by merely contacting the solid with copper(II) chloride or triflate ethanolic solutions. Different techniques such as powder XRD, N2 adsorption–desorption, elemental analysis, IR, XPS, EPR and EXAFS were combined together with an emphasis on quantification to reach a quasi-molecular description at each functionalisation step of the internal surface of the materials.
Studies in Surface Science and Catalysis | 2003
P. Reinert; B. Garcia; C. Morin; Pascal Perriat; O. Tillement; Laurent Bonneviot
Abstract Superstable mesoporous silicas LUS-1 templated using cationic surfactants of various chain lengths were synthesized in the presence of tosy late anions in basic media with low surfactant to silicium ratios. The highly structured hexagonal silica mesophases are stable in boiling water for several days and, after calcination up to 1093 K. A stabilizing hydrothermal treatment before calcination further improves the stability up to 1273 K. It is believed that the outstanding stability of the LUS-1 is related to the hydrophobic control obtained using an organic surfactant counterion in the surfactant-silicate interface during polycondensation.
Journal of Materials Chemistry | 2007
Tomohisa Miyajima; Sébastien Abry; Wen-Juan Zhou; Belén Albela; Laurent Bonneviot; Yasunori Oumi; Tsuneji Sano; Hideaki Yoshitake
We present here the results of the substitution of 3-bromopropyltriethoxysilane-grafted mesoporous SBA15 (pore size 7.6 nm) with a series of diamines, CH3NH(CH2)nNHCH3 (C2DA, C3DA and C6DA for n = 2, 3 and 6, respectively) or NH2(CH2)nNH2 (C4DA and C5DA for n = 4 and 5, respectively). The outcome of the reactions was closely related to the spacing of the surface bromopropyl groups. Amount of bromine that remained after the reaction decreased linearly with the amount of C2DA, and it disappeared completely when C2DA : Br = 1 : 1 in the initial reactant mixture. This result indicates the complete conversion of C2DA and Br by a one-to-one substitution (i.e. formation of a linear species). By contrast, the rate of decrease of Br was twice as fast during substitutions with amines other than C2DA when diamine/Br < 0.5 (in the initial mixture), suggesting a one-to-two substitution and the formation of a bridge species. We show that the C/N ratios in the elemental analysis after the complete substitution of Br are a simple and reliable indicator of the distributions of the pair spacings of the bromopropyl groups. The results are compared by a geometric calculation in which the configurations and the minimum limits of neighbouring distances are ignored. The formation of linear and bridge forms were confirmed by 13C-NMR analysis. Reactions using MCM41 (pore size 2.4 nm) and fumed silica were also explored for comparison. We found that the order of the pair spacings of the bromopropyl groups grafted onto these silicas was MCM41 < SBA15 ≪ fumed silica. This result disagrees with the outcome that was expected from the number of bromopropyl groups per unit nm2, 0.8, 1.1 and 1.2 for MCM41, SBA15 and fumed silica, respectively, which was derived from the BET specific surface area and bulk elemental analyses. All of these results are consistent with a mode of grafting where the reaction with silanols competes with diffusion into the pore channels.
Journal of Colloid and Interface Science | 2014
Zhaoyu Fan; Astrid Tay; Marc Pera-Titus; Wen-Juan Zhou; Samy Benhabbari; Xiaoshuang Feng; Guillaume Malcouronne; Laurent Bonneviot; Floryan De Campo; Limin Wang; Jean-Marc Clacens
A key challenge in biomass conversion is how to achieve valuable molecules with optimal reactivity in the presence of immiscible reactants. This issue is usually tackled using either organic solvents or surfactants to promote emulsification, making industrial processes expensive and not environmentally friendly. As an alternative, Pickering emulsions using solid particles with tailored designed surface properties can promote phase contact within intrinsically biphasic systems. Here we show that amphiphilic silica nanoparticles bearing a proper combination of alkyl and strong acidic surface groups can generate stable Pickering emulsions of the glycerol/dodecanol system in the temperature range of 35-130°C. We also show that such particles can perform as Pickering Interfacial Catalysts for the acid-catalyzed etherification of glycerol with dodecanol at 150°C. Our findings shed light on some key parameters governing emulsion stability and catalytic activity of Pickering interfacial catalytic systems. This understanding is critical to pave the way toward technological solutions for biomass upgrading able to promote eco-efficient reactions between immiscible organic reagents with neither use of solvents nor surfactants.
New Journal of Chemistry | 2008
Stéphanie Calmettes; Belén Albela; Olivier Hamelin; Stéphane Ménage; Fabien Miomandre; Laurent Bonneviot
A supported [Ru(dmp)2(Py@LUS)Cl]Cl complex (dmp = 2,9-dimethyl-1,10-phenantroline) was synthesised in LUS, a 2D hexagonal porous mesostructured silica, via a step-by-step approach for the sake of site isolation, unicity and localisation in the confined space of the nanopores of the silica matrix. A pyridine terminated tether, Py@LUS, was homogeneously distributed on the surface using a molecular stencil patterning technique, followed by reaction of [Ru(dmp)2Cl2] at 78 °C. All intermediate materials were thoroughly characterised with a panel of techniques, including X-ray diffraction, elemental analysis, 29Si and 13C solid state NMR, diffuse reflectance UV-vis and FT-IR spectroscopies, and cyclovoltamperometry. Site isolation, unicity and localisation are achieved in the confined space of the nanopores of the silica matrix. The final material is selectively active in the catalytic oxidation of methylphenylsulfide into sulfoxide.