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We describe here a simple protocol yielding small (2Sn nanoparticles (NPs) along with Pd homologues for sake of comparison.

fff; International audience; For the Suzuki–Miyaura C–C coupling, it is well accepted that the active catalytic species in the liquid phase are leached from the solid palladium precursor. This was demonstrated for shaped solid Pd precursors which allows fixed-bed applications in flow chemistry. Yet, many interesting solid Pd precursors, including supported nanoparticles (NPs), are available as finely divided powders that cannot be used in fixed-bed reactors because of the too high pressure drop generated. In this work, open cell foam materials (OCF) are used as supports for Pd/C, Siliacat-Pd(0) and Pd(II)-DPP catalysts powders and Pd(0) NPs. The coupling of 4-iodoacetophenone with phenylboronic acid is used as a model reaction to evaluate the activity of leached species. Some experiments with other aryl halides are also reported. It is shown that all the catalytic foams are able to leach active species and that trace amounts in the range 30–300 ppb of Pd in solution are sufficient to carry out the reaction while maintaining a low pressure drop.

Ozone abatement in aircraft is traditionally performed thanks to catalytic ozone converters, working at ca. 200 °C with combined homogeneous (thermal) and heterogeneous (catalytic) pathways. For en...

Four catalysts—1%Pd-2%Mn/γ-Al2O3, 1%Pd/γ-Al2O3, 2%Mn/γ-Al2O3 and γ-Al2O3—were synthesized via a sol–gel method and characterized using various techniques to evaluate their physicochemical, textural, surface and acidic properties. They were used in the catalytic transformation of ozone and nitrogen oxides using in situ Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) analysis. Different consecutive gas sequences were followed to unravel the poisoning role of nitrogen oxides and the possible reactivation by ozone. It has been proven that on palladium and manganese-based catalysts, the inhibition effect of nitrogen oxides was due to the formation of monodentate nitrites, monodentate, bidentate and bridged nitrates, which are difficult to desorb and decompose into gaseous NOx, either by oxidation or by thermal treatment. Interestingly, monodentate nitrites could be eliminated if the catalyst went through a co-adsorption of NOx and ozone prior to exposure in clean ozone flow. This transformation could be the reason why the catalytic conversion of ozone could return to its original value before the poison effect of nitrogen oxides.

Owing to the high-volume production of the silicone industry, in which hydrosilylation products are polluted by Pt, it is of major interest to develop alternative catalysts that would be based on non-noble metals and that would be easy to separate from the reaction products. In this context, we explore here the preparation of catalysts based on non-noble metal nanoparticles as alternatives to Pt complexes or non-noble metal complexes (main trend in academic research). We demonstrate here that isolated nickel nanoparticles in solution or deposited on silica can be used as catalysts for alkene hydrosilylation. The composition of the nickel nanoparticles (nickel silicide, metallic nickel or nickel oxide) is key for selectivity and activity. These catalysts which exhibited similar Ni particle sizes were tested in the challenging reaction of triethoxysilane with triethoxyvinylsilane. The heterogeneous catalyst based on metallic nickel nanoparticles was found to be the most promising and could be filtered off, leading to pure reaction products (no metal pollution). This result suggests that the exploration of non-noble metal nanoparticles and particularly diverse nickel (0) phases may be a key to the development of highly selective heterogeneous catalysts.

International audience; A process intensification study for the full hydrogenation of bio-derived platform molecule squalene (SQE) into squalane (SQA), using commercial heterogeneous Pd catalysts and Pd supported on carbon nanotubes (CNT) is reported. Pd/CNT shows a substantial improvement of the catalytic activity for the total hydrogenation of SQE into SQA thanks to cooperativities between Pd nanoparticles and single atoms simultaneously present on the CNT. However, the stirred reactor's productivity, scalability, and operability are limited by the exothermicity of the reaction (ΔrH = − 765 kJ.mol−1). The implementation of the Pd/CNT catalyst in flow was then studied after coating this catalyst on metallic open cell foams. Using the foam-based milli-reactor's characteristics, including high mass and heat transfer rates and safety, fully reduced SQA (>99 %) was obtained at 180 °C and 30 bar of H2 for a contact time of 1.45 min with a space–time yield of 68 molSQA.molPd−1.min−1. Finally, a scale-up strategy (7 fold) was successfully attempted in a commercially available pilot-scale reactor that meets further seamless scale-up requirements. A production capacity of 2 kg per day using a commercial intensified reactor with a reacting volume of 43.2 mL was obtained under mild conditions (120 °C and 30 bar of H2).

SSCI-VIDE+CARE+VML; International audience; In aircrafts, outside air is not directly fed to passengers, because it contains high ozone concentration at elevated altitudes. Catalytic converters are thus necessary to lower ozone concentration to authorized values. Such equipments already exist but have to evolve to take into account the energetic constraints of more electrical aircrafts. Concretely, ozone reduction has to be performed efficiently at temperatures lower than 100°C, so that the ozone concentration of fresh air entering the aircraft cabin does not exceed 100 ppb (for 3 hours) and 250 ppb instantly.To improve the ozone converter efficiency, different solutions car arise from catalyst and/or reactor optimisation, keeping in mind that the pressure drop must be kept very low.In this study, a focus was made on the reactor configuration, using a single commercial catalyst coated on different structures in order to find the best trade off between pressure drop and mass transfer efficiency.

The catalytic decomposition of ozone was carried out at 40 °C with a Pd/Al2O3 catalyst, in the presence or absence of nitrogen oxides traces. NOx were produced during the generation of ozone from air. Two set-ups were used to examine the possible effects of NOx poisoning, one fixed bed with a powder catalyst, and another using a monolith coated with the same catalyst. NOx were shown to significantly poison the catalyst, resulting in a decrease of ozone conversion over time on stream. NOx-free ozone feed can lead to the total recovery of the initial catalyst properties indicating a reversible poisoning.

International audience; This work describes the development of easy to prepare cobalt nanoparticles (NPs) in solution as promising alternative catalysts for alkene hydrosilylation with the industrially relevant tertiary silane MDHM (1,1,1,3,5,5,5-heptamethyltrisiloxane). The Co NPs demonstrated high activity when used at 30 °C for 3.5-7 h in toluene, with catalyst loadings 0.05-0.2 mol%, without additives. Under these mild conditions, a set of terminal alkenes were found to react with MD H M, yielding exclusively the anti-Markovnikov product in up to 99% yields. Additionally, we demonstrated the possibility of using UV irradiation to further activate these cobalt NPs in order to enhance their catalytic performances, but also to promote tandem isomerization-hydrosilylation reactions using internal alkenes, among them unsaturated fatty ester (methyl oleate), to produce linear products in up to quantitative yields.

A kinetic study concerning the self-metathesis of methyl oleate and methyl elaidate was performed, using a variety of NHC-ruthenium pre-catalysts, bearing either mesityl groups or di-isopropyl-phenyl groups on the NHC ligand and various trans ligands with respect to the NHC unit. We showed that the system can be satisfactorily described using one initiation constant per pre-catalyst and four propagation constants that, conversely, do not depend on the pre-catalyst. The difference of reactivity with oleate (Z) and elaidate (E) can be fully explained by the propagation parameters; the studied pre-catalysts initiate with the same rate starting from the Z or the E olefin. The ranking of the propagation parameters is driven by the thermodynamic equilibrium. The transformation rates of Z and E isomers is only driven by these propagation constants and nothing differentiates the initiation step.

This article presents an experimental kinetic study of the Suzuki&ndash, Miyaura reaction of 4-iodoacetophenone with phenylboronic acid catalyzed by the Herrmann&ndash, Beller palladacycle. This catalyst, together with the solvent (ethanol) and the base (sodium methylate), were chosen to ensure catalyst stability and reactants solubility all along the reaction. Based on the study of initial reaction rates, a quasi-first-order was found for 4-iodoacetophenone with a first-order dependence on the initial concentration of palladium. A zero-order was found for the base and the phenylboronic acid. The oxidative addition step of the mechanism was thus considered as the rate determining step. A global rate law was derived and validated quantitatively. A global activation energy, with an average value of ca. 63 kJ/mol was determined.

International audience; (C.d.B.); Tel.: +33-4-72-43-1755 (V.M.) † These authors contributed equally to this work. Abstract: A critical review of conclusions about the putative heterogeneous mechanism in the Suzuki-Miyaura coupling by supported Pd solids is reported. In the first section, the turnover frequencies (TOF) of 20 well-established homogeneous catalysts are shown to be in the range 200 to 1,000,000,000 h −1. The evidences used to prove a heterogeneous mechanism are discussed and another interpretation is proposed, hypothesizing that only the leached species are responsible for the catalytic reaction, even at ppb levels. Considering more than 40 published catalytic systems for which liquid phase Pd content have been reported, activities have been computed based on leached Pd concentrations and are shown to be in the range TOF 150 to 70,000,000 h −1. Such values are compatible with those found for the well-established homogeneous catalysts which questions the validity of the conclusions raised by many papers about the heterogeneous (solid) nature of Suzuki-Miyaura catalysis. Last, a tentative methodology is proposed which involves the rational use of well-known tests (hot-filtration test, mercury test.. .) to help to discriminate between homogeneous and heterogeneous mechanisms.

International audience; The homogeneous vs heterogeneous contributions when using solid catalysts for the Suzuki-Miyaura coupling is still disputed. Leaching is often observed and quantified albeit with unclear conclusions about contributions of the leached species and of the solid catalyst to the global catalytic activity. In this work, a new flow reactor design to discriminate both contributions is proposed. With the help of a simple reactor model, it has been possible to conclude that the coupling of 4-iodoacetophenone with phenylboronic acid proceeded with the leached homogeneous species only, whatever the solid Pd/silica used, whereas chloro-derivatives behaves differently. This reactor is simple to build and could be of general use to reveal actual heterogeneous vs homogeneous catalysis for many reactions. Keywords Suzuki-Miyaura · Heterogeneous · Leaching · Palladium The knowledge of the reaction location is of prime importance both to design efficient industrial processes and to understand the underlying fundamental mechanisms. For example, many catalytic processes are operated with heterogeneous (solid) catalysts for easier separation and downstream treatments thus to lower operating costs. However, when the fluid phase is a liquid, it appears that the knowledge of the reaction location is not straightforward. Indeed, active catalytic species may leach from the solid, which is then a simple catalyst precursor, and solubilizes in the liquid phase in which it catalyzes the reaction. Several papers including recent reviews have analyzed such situations for many different type of catalytic processes.[1,2] One must realize that the design of a catalytic reactor is largely based on the assumption of the reaction location simply because the reaction time, i.e. the contact time between the

Stainless steel open-cell solid foams of various linear pore densities (20, 40, 60 PPI) are wash-coated with a commercial catalyst and are evaluated as internals for G-L-S reactions in co-current up-flow configuration. Hydrodynamics parameters such as liquid mean residence time, axial dispersion and pressure drop have been determined for an air/water system with superficial velocities between 0.8 mm/s and 25 mm/s for liquid and between 100 and 900 mm/s for gas. A generic piston-dispersion model represents well the liquid hydrodynamics and is used to estimate axial Peclet number and mean residence time for this phase. The Peclet number appears to increase with liquid velocity and foam linear pore density (5 Pe Pe Pe ɛ L −1 were obtained at low Re numbers, which is one order of magnitude higher than in up-flow fixed beds. A set of correlations is derived for the calculation of the gas/liquid and liquid/solid contributions to external mass transfer and allows explaining the unique bell-shaped Re dependence displayed by the overall mass transfer coefficient.

International audience; Developing new stirred gas-liquid-solid reactors with high mass transfer capabilities is still a challenge. In this publication, we present a new concept of multiphase reactor using a stationary catalytic foam and a gas-inducing impeller. The gas-liquid (GL) and liquid-solid (LS) mass transfer rates in this reactor were compared to a stirred reactor with basket filled with beads. Batch absorption of hydrogen and measurement of α-methylstyrene hydrogenation rate on Pd/Al 2 O 3 catalyst were used to evaluate k GL a GL coefficients and k LS coefficients, respectively. With similar LS transfer rates to the basket-reactor and much higher GL transfer rates, the new reactor reveals a very promising tool for intrinsic kinetics investigations.

International audience; The electrochemical in situ regeneration of spent Pd/C/foam catalysts was investigated using a modified Mahoney-Robinson reactor (RM). The same reactor was used for reaction and regeneration experiments with and without removal/weighing of the catalyst between each measurement. The feasibility of the electrochemical regeneration was assessed by monitoring the catalyst activity versus cumulative turnover number (TON). The results showed that the catalyst activity was fully recovered after regeneration and that the catalyst had the same deactivation rate after several reaction/regeneration cycles. The influence of the foam pretreatment step and of the pH electrolyte solution on the catalyst loss was also studied. A basic pretreatment of the foam before the catalyst coating led to a significant improvement of the catalyst adherence on the foam.

International audience; An Ir(NHC) supported catalyst is used in the selective hydrogenation of terpinen-4-ol to cis p-menthan-4-ol. Its activity, selectivity and stability are compared to those of a homogeneous homologue [IrCl(COD)MesImPr] and to a commercial Pd/C. The solid Ir catalyst is much more selective than the Pd catalyst (92 vs. 42% at 80°C) but also more active, more selective and more stable than the iridium complex in solution. For the first time, a supported catalyst shows an enhanced activity with respect to a complex in a diastereoselective hydrogenation reaction.

A catalyst containing small (ca. 2.5 nm) and crystalline Pt nanoparticles embedded into the walls of a mesostructured silica framework was found to be highly active in alkene hydrosilylation reaching TONs of ca. 105. More importantly, no Pt leaching was detected. This result is remarkable because Pt leaching is a recurrent problem in alkene hydrosilylation, which often prevents heterogeneous catalysts from being used industrially. This result is in contrast to the significant Pt leaching observed for other Pt/SiO2 catalysts.

The reverse flow adsorber (RFA) can be used as a catalytic reactor for homogeneous catalysis to avoid the issues of catalyst separation. The RFA combines the reverse flow circulation and the separation of the dissolved solute from the liquid homogeneous mixture. In this work, the RFA is modeled and simulated in order to evaluate its separation performances and its behavior. The studied adsorber is a single adsorption/desorption packed bed, and the reversal of flows is applied to keep the solute inside the bed as longer as possible while minimizing its outlet concentration (leaching). The chosen one dimensional model accounts for the axial dispersion and the non-equilibrium effects (mass transfer resistances, etc). The numerical method of lines (MOL) is used to solve the partial differential algebraic model equations (PDAEs). Two cases are studied; the first one is the dynamic of the homogeneous solute concentration starting from a pre-loaded column and without solute addition. The second case considers operations with continuous solute side stream addition. In the first case, leaching persists until the initially pre-loaded adsorption column with solute is completely emptied thus demonstrating unsteady-state operations in contrast with previous works. To compensate leaching, solute makeup is added at the center of the column. This leads, after priming a number of cycles, to a stationary periodic state operation.

International audience; Whereas carbon is a major catalyst support, namely in pharmaceutical industry , its immobilisation on structured objects has scarcely been studied. This article presents the comparison of two methods aiming at coating ceramic and metallic supports with a carbon layer. The method involving a suspension of black carbon is easy to use but leads to less adherent layers than the method involving the carbonization of poly(furfuryl alcohol). On the other hand, the former method is the one that allows to prepare more active catalysts for nitrobenzene hydrogenation. Then, the suspension formulation has been improved to enhance the carbon adhesion.

α-methylstyrene catalytic hydrogenation on Pd/Al2O3 is frequently used to characterize new reactors. However, whereas many authors report some problems of reproducibility or possible poisoning of the catalyst, no consistent advice is available in the literature to carry out the reaction without these problems. This work points out the inhibition of the reaction by trace amounts of water. An experimental procedure is explained to guarantee the reproducibility of the measures. L'hydrogenation catalytique de l'α-methylstyrene est frequemment utilisee pour la caracterisation de reacteurs de laboratoire. Cependant, en depit des problemes de reproductibilite ou d'empoisonnement du catalyseur rapportes dans la bibliographie, il n'existe aucune recommandation permettant de mener a bien cette reaction dans des conditions optimales. Ce travail met en evidence l'inhibition de la reaction par des traces d'eau. Une procedure experimentale est proposee pour garantir la bonne reproductibilite des mesures.

Colloidal suspensions of monodisperse platinum nanoparticles of 2 nm diameter have been used to catalyze the hydrosilylation of 1-octene with a polymethylhydrosiloxane. The nanoparticles were found to be as efficient as Karstedt's complex, showing that colloid formation from homogeneous species during hydrosilylation reactions is not necessarily a deactivation pathway. These results also reactivated the debate on whether Karstedt's complex was truly homogeneous or colloidal during catalysis.

International audience; tel: +33 (0)4 72 43 17 55 ­ Fax: +33 (0)4 72 43 16 73 The deposition of TiO 2 ­P25 on Pyrex glass is studied in order to propose a procedure for obtaining uniform and adherent thin films with a controlled thickness in the range between fractions of micrometer to a few tens of micrometers. Different deposition methods such as spray­coating, dip­coating and drop­coating of liquid suspensions of TiO 2 ­P25 powder are considered. The effect of pretreatment of the glass support, as well as post­deposition steps such as drying condition and thermal treatment are also reported. A basic glass pretreatment and an acidic TiO 2 suspension are chosen for an optimized adherence of the film. Drop­coating, associated with a slow drying under 55% relative humidity and a high temperature thermal treatment is the method of choice to prepare coated glass slides in a large range of film thicknesses.

Structured objects of different characteristic size have been coated with γ -Al2O3. The oxide layers are characterised in terms of thickness, surface area, crystalline phase, adherence on the support surface, etc. According to the structured object, adherent oxide layers from less than 1 to around 200 μ m have been obtained.

Analysis of the literature on α-methylstyrene (AMS) hydrogenation reveals very large variations in the reported reaction rates. The presence of traces of water and mass-transfer limitations make reproducible intrinsic kinetic determination difficult. Under anhydrous conditions, the intrinsic kinetic law was, nevertheless, determined under a wide range of operating conditions: 0.5−100 wt % AMS, 0.1−0.6 MPa, 273−320 K, with an activation energy of 38.7 ± 1.5 kJ·mol-1.

The structure of polysiloxane copolymers obtained by hydrosilylation of 1-octene with polymethylhydrosiloxane (PMHS) was analyzed by 29Si NMR spectroscopy and revealed a tendency to form block copolymers. Although all the platinum catalysts that were used showed a tendency to form some block structures, only Karstedt catalyst led to well defined block copolymers. However, the tacticity of these copolymers could not be determined using Heteronuclear Multiple Bond Correlation (HMBC) 2D (1H/ 29Si) NMR technique. The following criteria were found to affect the structure of the hydrosilylation product: low SiH conversion, the “age” of the Karstedt catalyst (low TON) and high octene/SiH ratios.

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The deactivation and regeneration of Pd/carbon coated support catalysts, used during nitrobenzene hydrogenation, were studied. Three methods have been tested: electrochemical treatment, chemical oxidation and oxygen plasma treatment. The regenerated catalysts were characterized by physisorption of nitrogen (BET method) and were compared with the activities of fresh catalysts. It was found that the electrochemical treatment allows the complete regeneration of the catalyst, without any modification of textural properties. Simple chemical oxidation did not allow the activity recovery of Pd catalysts and led to modification of the textural properties of carbon. Finally, the catalyst may be regenerated also by plasma method, albeit with some increase of the pore diameter.

An original process based on cold plasma assisted polymerization of tetramethyldisiloxane (TMDSO) in the presence of O 2 was developed to cover substrates showing various shapes (plate and foam). In the frame of catalytic application, this coating has to act as a bonding layer for the deposition of active phase such as VO x/TiO 2 well-known for its properties in NO x and volatile organic compounds abatement and in the production of chemical intermediates. Good results were obtained by the deposition of a 5- lm thick polysiloxane film followed by a thermal treatment under air at 650 8C and by a remote nitrogen plasma post treatment. This procedure led to a silica-like layer allowing its coating in an aqueous suspension of TiO 2. Such a multilayered material can be obtained homogeneously on the whole surface of a sample showing a 3D open geometry like metallic foam. Characterizations of the different steps of the elaborated multilayer material were performed by Fourier transformed infrared spectroscopy, Raman spectrometry, X-ray photoelectron spectroscopy, and electron probe micro-analyzer. POLYM. ENG. SCI., 51:940– 947, 2011. a2011 Society of Plastics Engineers

Two model reactions were used to show the influence of catalytic foams on improving heat transfer. The catalytic performances were compared to those observed when using the same reactors packed with catalytic powder or beads. One reaction was the exothermic oxidative dehydrogenation of propane which was investigated on 7%V2O5/TiO2 coated on stainless steel foam. A silica layer was first deposited on the foam surface by Remote Plasma Enhanced Chemical Vapour Deposition to avoid poisoning of active phase by iron species, to favour the anchoring of TiO2 support and to accommodate the difference of dilatation coefficients. When comparing catalytic foams with powders in the same reactor, the selectivity to propene at isoconversion was higher by 12–45 mol% for the same amount and composition (7%V2O5/TiO2) of the active phase and in the same operating conditions (contact time, C3/O2 ratio, temperature range). The other reaction was the endothermic dehydrogenation of methylcyclohexane on 2%Pt/Al2O3 directly coated on foams and on molecular sieve beads. To study the influence of heat and mass transfers, the material (FeCrAlloy or alumina) and porosity (81–97%) of foams were varied. It was found that, even for highly exothermic or endothermic reactions not limited by external transport, the coated foams significantly increased the effective conductivity of catalytic beds, the denser foam leading to higher effective conductivity.

International audience; Viscosities of the ternary and binary mixtures of 1-octene, Rhodorsil H68, Rhodorsil 308V750 have been measured at different temperatures between 293.15 and 353.15 K and at atmospheric pressure. Two correlations were established to predict the viscosity of all mixtures. The first is a statistical expression deduced from an experimental design. The second is based on an additivity law and the temperature effect on binary mixtures.

Catalytic structured reactors are designed to improve both heat and mass transfers during reactions in the presence of catalytic layers. The know-how acquired in the coating of stainless steel walls by catalytic layers of VO x /TiO 2 , active in the abatement of volatile organic compounds and in the production of chemical intermediates, was extended to metallic foams. The preferred and original way was to first make a deposit of a silica-like primer by cold plasma assisted polymerization of tetramethyldisiloxane in the presence of oxygen. After mineralisation, this layer was supposed to act as a barrier against poisoning by elements of the metallic substrate, as well as a stabilizer of the catalyst layers. The cells of the foam were homogeneously covered by a 5 μm-thick polysiloxane film ending in ca. 1 μm thick silica after calcination. After studying the textural properties and zeta potential of aqueous suspensions of TiO 2 particles, the silica-coated foams were dipped in a 37 wt.% aqueous suspension of TiO 2 -anatase. The final VO x /TiO 2 /SiO 2 /foams were obtained by grafting polyvanadate specie in sol–gel medium. At every step of coating, the multilayer materials were studied mainly by X-ray Photoelectron Spectroscopy and Electron Probe Micro-Analysis. Moreover the mechanical and chemical stability of the successive coatings was checked.

An alternative to the classical hydrodesulfurization process is proposed, based on the formation and subsequent removal of insoluble charge-transfer complexes between suitable π-acceptors and alkylated dibenzothiophenes.

International audience; The catalytic total oxidation of toluene is used to bring the required calories to restore hydrogen from methylcyclohexane (MCH). Two coupled reactions, both catalyzed by Pt/alumina, are thus considered in one autothermal heat-exchanger reactor (HER): endothermic dehydrogenation of methylcyclohexane and catalytic combustion of less than 10% of produced toluene (6% for the chemical reaction, about 4% for heat losses). Both reactions are carried out at 350 °C. Methylcyclohexane and toluene light-off curves have been performed in one elementary module. Methylcyclohexane combustion has been eliminated due to its safety drawbacks, although the MCH combustion provides best stability to autothermal HER.

International audience; Different types of aqueous TiO2-P25 suspensions were prepared and their properties, including rheological behaviour and zeta potential, were studied. Then, TiO2 suspensions were used to elaborate TiO2 coatings on various substrates (cordierite monolith, stainless steel plates and beta-SiC foam) using a dip-coating method. The relationship between the suspension stability and the coating adhesion has been considered. The structural and morphological characterisation of TiO2 coatings has been performed using scanning electron microscopy, X-ray diffraction and other methods. Finally, the photocatalytic properties of the materials have been determined by studying the photooxidation of aqueous ammonia.

International audience; The deposition of thick layers of -Al2O3 is often performed by the washcoating method consisting of immersing the object to coat in a slurry containing -Al2O3 powder and nitric acid. Although this method gives very satisfying results in terms of adherence and BET surface, it shows a bad reproducibility in terms of viscosity of the slurry and thus layer thickness. Characterizations of the slurry were performed at different preparation steps to try to understand and control the chemistry involved.

Bromination of (R)‐2,2′‐(diphenylphospnino)‐1,1′‐binaphthyl (BINAP) in [Hmim]PF6 ionic liquid was performed with N‐halosuccinimides at 110°C during 12 h, affording the 4,4′‐dibromoBINAP in high yield. The ionic liquid was recycled four times without modification of selectivity or efficiency.

Bromination of (R)‐2,2′‐(diphenylphospnino)‐1,1′‐binaphthyl (BINAP) in [Hmim]PF6 ionic liquid was performed with N‐halosuccinimides at 110°C during 12 h, affording the 4,4′‐dibromoBINAP in high yield. The ionic liquid was recycled four times without modification of selectivity or efficiency.

International audience; When surface-supported chemical reactions are performed in microsystems, high production rate cannot be obtained due to the intrinsically low surface area. Increasing the active surface area of silicon microsystems is a challenge that is addressed in this paper using two original approaches: (i) modifying the structure of silicon by creating nanostructures (black silicon) using conventional etching processes of silicon micromachining or (ii) depositing a layer of porous _-alumina by washcoating a colloidal suspension of boehmite onto the silicon surface. The catalytic oxidation of carbon monoxide on platinum was chosen as a first test reaction in the domain of heterogeneous catalysis. In order to perform this reaction, platinum was either deposited by sputtering on silicon devices with black silicon nanostructuration, or impregnated inside the porosity of an alumina layer previously deposited on a silicon device. For specific biological applications, such as proteins analysis, some biological reactions could be advantageously achieved in microsystems using surface-supported species. As an example, an enzymatic reaction was carried out usingsilicon devices modified with black silicon nanostructuration and further functionalized with trypsin as a model enzyme. The catalytic activity was compared between silicon devices with the same two types of catalysts, comprising or not an enhancement of the surface activity. A minimum 10- fold increase in catalytic activity was estimated from kinetic measurements and represents the augmentation of the active surface really available for reactions. It was also shown how these catalytic materials were integrated in a microreactor increasing its catalytic active surface without modifying its global size.

International audience; A continuous micro-structured reactor equipped with a perforated (5 μm) membrane is used for the investigation of the gas–liquid–solid asymmetric hydrogenation of ethylpyruvate on a Pt/γ-Al2O3 catalyst modified with chiral inductors under high hydrogen pressure (45 bar). Up to eight chiral inductors have been evaluated, the best enantioselectivity (63%) being obtained with cinchonidine. The very low reaction volume (100 μl) offers short operating time. Solvent effect, deactivation studies and the effect of modifier leaching are also reported.

A library of 5,5′-disubstituted BINAP derivatives were synthesized in good yield from optically pure BINAP and evaluated for the Rh-catalyzed homogeneous asymmetric hydrogenation of (α)-acylaminoacrylate ester, with ee of up to 77% being obtained with the phenyl derivative. The enantiomeric excess variation was followed according to the groups introduced in the 5,5′-position of BINAP and for a range of pressure from 5 to 30 bar.