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International audience; The oxidation of neopentane was studied in jet-stirred reactors at atmospheric pressure over a temperature range 500–850 K and ϕ = 0.5. The products were analyzed with chromatographic, mass spectrometric, and photoelectron spectroscopic setups complemented with theoretical calculations. This combination provides a comparison of photo-ionization mass spectrometry and gas chromatography for the quantification of mole fractions and highlights the relevant differences between them, while mass-tagged photoelectron spectroscopy sheds light onto the isomeric distribution. The new data and corresponding analyses are expected to provide valuable guidance for an extension of the kinetic model and the choice of experimental methods. The main first and second O2-addition products were observed in agreement with the literature (e.g., 3,3-dimethyloxetane, acetone, isobutene, and γ-ketohydroperoxide). The simulated mole fractions of the products using a literature kinetic model were compared to the experimental results. Even though the kinetic model has been validated previously, significant discrepancies between the measured and simulated mole fractions of 2-methylpropanal and methacrolein, two fuel-specific low-temperature oxidation products, were found. Furthermore, some experimentally observed species related to γ-ketohydroperoxide decomposition were not predicted indicating that the model is incomplete. The detection of 2-methylpropanal and formic acid highlighted the importance of the Korcek-type pathway.

International audience; Lignocellulosic biomass is the most abundant carbon source and it is a base of the whole biorefinery concept. Levoglucosan (1,6-anhydro-β-D-glucopyranose) (LG) is an anhydrous sugar formed as a major product during pyrolysis of cellulose. LG might be a promising chemical platform. It can be converted to different high added-value chemicals such as levoglucosenone, 5-hydroxymethylfurfural and styrene directly or through a glucose intermediate via chemical, catalytic and biochemical processes. In this critical review we focus not only on the pyrolytic methods for the synthesis of levoglucosan, but above all also on the recent scientific progress in the chemical and biochemical transformation of levoglucosan to highly valued compounds. The catalytic performances of the heterogeneous and enzymatic catalytic systems used for different reactions of LG conversion are reviewed. Specific properties of the active sites, roles of additives, and solvents and conditions are discussed in detail. We conclude on recommendations to further improve LG conversion to high added-value products.

International audience; The determination of the abundances of the CHx, C=O and aromatic groups in chondritic Insoluble Organic Matter (IOM) and coals by Infrared (IR) spectroscopy is a challenging issue due to insufficient knowledge on the absorption cross-sections and their sensitivity to the molecular environment. Here, we report a calibration approach based on a 13C synthetic model material whose composition was unambiguously determined by Direct-Pulse/Magic Angle Spinning Nuclear Magnetic Resonance (DP/MAS NMR). Ratios of the cross-sections of the CHx, C=O and aromatic groups have been determined, and the method has been applied to IOM samples extracted from four chondrites as Orgueil (CI), Murchison (CM), Tagish Lake (C2-ungrouped) and EET 92042 (CR), and to a series of coals. The estimate of the aliphatic to aromatic carbon ratio (nCHx/nAro) in IOM samples from Orgueil, Murchison and Tagish Lake chondrites is in good agreement with Single-Pulse/NMR estimates earlier published, and is lower by a factor of 1.3 in the case of the CR chondrite EET 92042 (but the error bars overlap). In contrast, the aliphatic to carbonyl ratio (nCHx/nC=O) is overestimated for the four chondrites. These discrepancies are likely due to the control of the absorption cross-section of the C=O and C=C bonds by the local molecular environment. Regarding coals, the use of published NMR analyses has brought to light that the integrated cross-section ratio ACHx/AAro varies with the vitrinite reflectance over an order of magnitude. Here as well, the local oxygen speciation plays a critical control in AAro, which decreases with increasing the vitrinite reflectance. We provide an analytical law that links ACHx/AAro and vitrinite reflectance, which will allow the determination of nCHx/nAro for any coal sample, provided its vitrinite reflectance is known.

We report the design and synthesis of europium-doped gadolinium oxysulfide nanoscintillators Gd2 O2 S:Eu3+ conjugated with two different photosensitizers (PSs): a zinc chlorin (ZnTPC) and a zinc phtalocyanine (ZnPc) by covalent bonding through a layer of N-(3-trimethoxysilylpropyl)diethylenetriamine (TPDA). These conjugates were designed to be activated under X-ray excitation to allow a photodynamic effect, although this desired outcome was not achieved in this study. The monodispersed nanoparticles of ∼70 nm diameter were pegylated to be stabilized in aqueous suspension. It was shown that the PSs conserved their photophysical properties once conjugated to the nanoscintillator and efficient singlet oxygen was obtained upon photo-irradiation. However, no energy transfer was observed from the nanoscintillator to the photosensitizer neither under photo- nor X-ray irradiation.

International audience; This paper presents energy transfer occurring in small organically modified core-shell nanoparticles (core lanthanide oxide, shell polysiloxane) (diameter < 10 nm) conjugated with photosensitizers designed for photodynamic therapy applications. These nanoparticles covalently encapsulate a photosensitizing PDT drug in different concentrations. Stable dispersions of the nanoparticles were prepared and the photophysical properties of the photosensitizers were studied and compared to those of the photosensitizers in solution. Increasing the photosensitizer concentration in the nanoparticles was not found to cause any changes in the absorption properties while fluorescence and singlet oxygen quantum yields decreased. As a possible explanation, we have suggested that both long distance energy transfer such as FRET and self-quenching could occur into the nanoparticles. A simple "trend" model of this kind of energy transfer complies with results of experiments on steady state fluorescence and singlet oxygen luminescence.

International audience; Doping of transition metals within a semiconductor quantum dot (QD) has a high impact on the optical and magnetic properties of the QD. In this study, we report the synthesis of Mn 2+-doped Ag−In−Ga−Zn−S (Mn:AIGZS) QDs via thermolysis of a dithiocarbamate complex of Ag + , In 3+ , Ga 3+ , and Zn 2+ and of Mn(stearate) 2 in oleylamine. The influence of the Mn 2+ loading on the photoluminescence (PL) and magnetic properties of the dots are investigated. Mn:AIGZS QDs exhibit a diameter of ca. 2 nm, a high PL quantum yield (up to 41.3% for a 2.5% doping in Mn 2+), and robust photo-and colloidal stabilities. The optical properties of Mn:AIGZS QDs are preserved upon transfer into water using the glutathione tetramethylammonium ligand. At the same time, Mn:AIGZS QDs exhibit high relaxivity (r 1 = 0.15 mM −1 s −1 and r 2 = 0.57 mM −1 s −1 at 298 K and 2.34 T), which shows their potential applicability for bimodal PL/magnetic resonance imaging (MRI) probes.

International audience; The present work studies the bubble formation in viscous liquids with the viscosity ranging from 5 to 400 mPa s by using a high-speed digital camera. The experiment was carried out in a flow-focusing device with square cross-section of 600 x 600 mu m. Results show that the viscous shear stress strongly influences the dynamics of bubble formation, including the shape and size of bubbles. The bubble size follows power-law relations with the gas flow rate, the flow rate and viscosity of the liquid phase respectively, indicating that bubbles formed in viscous fluids are controlled by a combination of squeezing mechanism and shearing mechanism. Therefore, the bubble size can be predicted by a power law function depending on the flow rate ratio of gas and liquid phases phi representing the squeezing mechanism and capillary number Ca representing the shearing mechanism. In addition, the dynamics of bubble formation in viscous liquids in a flow focusing device is also analyzed.

International audience; Tb2O3 coated with a polysiloxane layer is a biocompatible nanoscintillator that exhibits an appropriate pattern of biodistribution after injection. In this contribution, we combine this nanosystem with porphyrin molecules that are able to generate singlet oxygen, a major cytotoxic agent for photodynamic therapy application. Using time-resolved laser spectroscopy and singlet oxygen probes, we demonstrate this combination is suitable for singlet oxygen generation induced by X-ray and provide a physical study of the energy transfer observed between the nanoscintillator and the porphyrin. Combined with a radiotherapy protocol, the proposed nanohybrid system presents a combination of physical, chemical, and biological properties that make it a good candidate for photodynamic effects in deep tissues.

International audience; Photodynamic therapy (PDT) is an emerging theranostic modality for various cancer as well as non-cancer diseases. Its efficiency is mainly based on a selective accumulation of PDT and imaging agents in tumor tissue. The vascular effect is widely accepted to play a major role in tumor eradication by PDT. To promote this vascular effect, we previously demonstrated the interest of using an active- targeting strategy targeting neuropilin-1 (NRP-1), mainly over-expressed by tumor angiogenic vessels. For an integrated vascular-targeted PDT with magnetic resonance imaging (MRI) of cancer, we developed multifunctional gadolinium-based nanoparticles consisting of a surface-localized tumor vasculature targeting NRP-1 peptide and polysiloxane nanoparticles with gadolinium chelated by DOTA derivatives on the surface and a chlorin as photosensitizer. The nanoparticles were surface-functionalized with hydrophilic DOTA chelates and also used as a scaffold for the targeting peptide grafting. In vitro investigations demonstrated the ability of multifunctional nanoparticles to preserve the photophysical properties of the encapsulated photosensitizer and to confer photosensitivity to MDA-MB-231 cancer cells related to photosensitizer concentration and light dose. Using binding test, we revealed the ability of peptide-functionalized nanoparticles to target NRP-1 recombinant protein. Importantly, after intravenous injection of the multifunctional nanoparticles in rats bearing intracranial U87 glioblastoma, a positive MRI contrast enhancement was specifically observed in tumor tissue. Real-time MRI analysis revealed the ability of the targeting peptide to confer specific intratumoral retention of the multifunctional nanoparticles.

International audience; Direct information about fluids under supercritical water conditions is unfeasible due to the engineering restrictions at high pressure and high temperature. Numerical investigations based on computational fluid dynamics (CFD) calculations are widely used in order to get extensive information on the fluid behavior, particularly to help the design of a new reactor. This paper presents the numerical investigations performed on an original supercritical water device, especially in the level of the reactor. CFD calculations allow to design and optimize the present reactor described in this study. Currently, this process produces some nanometric oxide powders in continuous way with a production rate of 10-15g h(-1). Examples of synthesized nanomaterials are presented in order to prove the process efficiency. Crystalline ZrO(2) and TiO(2) were produced from a metallic salt and an organometallic as precursors, respectively. XRD and HRTEM analyses show nanosized particles with an uniform size distribution (

Aim: The strategy developed aims to favor the vascular effect of photodynamic therapy by targeting tumor-associated vascularization using peptide-functionalized nanoparticles. We previously described the conjugation of a photosensitizer to a peptide targeting neuropilin-1 overexpressed in tumor angiogenic vessels. Materials & Methods: In this study, we have designed and photophysically characterized a multifunctional nanoparticle consisting of a surface-localized tumor vasculature targeting peptides and encapsulated photodynamic therapy and imaging agents. Results & Conclusion: The elaboration of these multifunctional silica-based nanoparticles is reported. Nanoparticles functionalized with approximately 4.2 peptides bound to recombinant neuropilin-1 protein. Nanoparticles conferred photosensitivity to cells overexpressing neuropilin-1, providing evidence that the chlorin grafted within the nanoparticle matrix can be photoactivated to yield photocytotoxic effects in vitro.

International audience; The adsorption of a sunflower protein extract at two air− water and oil−water interfaces is investigated using tensiometry, dilational viscoelasticity, and ellipsometry. For both interfaces, a three step mechanism was evidenced thanks to master curve representations of the data taken at different aging times and protein concentrations. At short times, a diffusion limited adsorption of proteins at interfaces is demonstrated. First, a two-dimensional protein film is formed with a partition of the polypeptide chains in the two phases that depends strongly on the nature of the hydrophobic phase: most of the film is in the aqueous phase at the air−water interface, while it is mostly in the organic phase at the oil−water interface. Then a three-dimensional saturated monolayer of proteins is formed. At short times, adsorption mechanisms are analogous to those found with typical globular proteins, while strong divergences are observed at longer adsorption times. Following the saturation step, a thick layer expands in the aqueous phase and appears associated with the release of large objects in the bulk. The kinetic evolution of this second layer is compatible with a diffusion limited adsorption of the minor population of polymeric complexes with hydrodynamic radius R H ∼ 80 nm, evidenced in equilibrium with hexameric globulins (R H ∼ 6 nm) in solution. These complexes could result from the presence of residual polyphenols in the extract and raise the question of the role of these compounds in the interfacial properties of plant protein extracts.

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Cyclic and aromatic hydrocarbons are important components of usual commercial fuels, with C6-rings being among the most abundant cyclic structures. The combustion chemistry of C6-rings involves different levels of unsaturation, either as initial fuels (aromatics, naphtenes, …) or as intermediates formed during their combustion. In this work the ignition delays of cyclohexane, cyclohexene, 1,3-cyclohexadiene and 1,4-cyclohexadiene are systematically studied using experiments and kinetic modeling. Shock tube experiments were performed at high-temperature (above 1200 K) and for mean pressures of 6 atm. A detailed chemical kinetic model was developed that includes the combustion chemistry of the four cyclo-C6 fuels. Electronic structure calculations were performed at the CCSD(T)/CBS//B2PLYP-D3 level of theory on the pericyclic reactions of the unsaturated fuels. Pressure-dependent rate coefficients were computed by solving the master equation, and included in the mechanism. The model was validated against the new ignition data and against data of the literature. It was able to reproduce the experimental ranking of reactivity: cyclohexene > 14-CHD > cyclohexane > benzene ≈13-CHD. Kinetic analyses were performed to explain this difference of reactivity. It is shown that pericyclic reactions play a major role in the initial decomposition of the unsaturated fuels.

International audience; A theoretical study of the thermal decomposition of β-1,4-xylan, a model polymer of hemicelluloses, is proposed for the first time. A mechanism based on unimolecular concerted reactions is elaborated in a comprehensive way. Elementary reactions, such as dehydrations, retro-aldol, retro Diels–Alder, retro-ene, glycosidic bond fissions, isomerizations, etc., are applied to β-1,4-xylan, as well as to the fragments formed. At each stage of the construction of the mechanism, the fragments previously retained are decomposed and the low energy paths are selected to define new fragments. Energy barriers are computed at the CBS-QB3 level of theory and rate coefficients of important reactions are calculated. It is shown that the main reaction pathways can be modelled by reactions involving two specific fragments, which react in closed sequences, similarly to chain-propagating reactions. The proposed reaction scheme allows to predict important species observed during the pyrolysis of xylan, such as aldehydes or CO. In addition, we show that dehydrations require high activation energy and cannot compete with the other reactions. Therefore, it seems difficult to explain, by means of unimolecular homogeneous gas phase reactions, the significant formation of specific species such as furfural as reported by several authors.

International audience; Urea is used in Selective Catalytic and Non Catalytic Reduction (SCR and SNCR) methods for NOx abatement in post-combustion processes. The decomposition of urea-water solution in exhaust systems leads to the formation of NH3, which is the NOx reducing agent. However, the decomposition of urea can also lead to the formation of unwanted pyrolysis by-products, particularly in region where the temperature and pressure conditions are not optimal or via wall-spray interactions. In this study, a gas phase kinetic model for urea pyrolysis is proposed to explain the growth of pyrolysis by-products of urea, and in particular, the route of formation of the major product: isocyanuric acid. Systematic theoretical calculations, using electronic structure calculations and transition state theory, were performed to explore all the possible unimolecular and bimolecular reactions of the initial species. Kinetic modeling was used to select the relevant reaction pathways at each growing step, and their rate constants were refined using CCSD(T)/CBS//B2PLYP-D3/cc-pvTZ calculations. Quantum calculations showed that the postulated growing schemes of the literature, based on the successive urea + HNCO ⇆ biuret, biuret + HNCO ⇆ triuret followed by the cyclization of triuret into isocyanuric acid are not energetically favored. It is observed that the most favored reaction route to isocyanuric acid involves carbamimidic acid, the urea tautomer, that first yields biuret in a reaction with HNCO and then is involved in the formation of triuret by reacting with a decomposition product of biuret. Isocyanuric acid is produced from the reaction between HNCO and the same decomposition product of biuret. This new mechanism of formation of isocyanuric acid is tested at different conditions to explore its most favored conditions of formation in the gas phase. Exploratory simulations of a pseudo condensed phase are also performed to qualitatively simulate condensed phase experiments and explain the observed pyrolysis yields.

International audience; The understanding of the thermal decomposition chemistry of chemical warfare nerve agents is largely limited by the scarcity of kinetic data. Because of the high toxicity of these molecules, experimental determination of their chemical properties is very difficult. In the present work, a comprehensive detailed kinetic model for the decomposition of sarin and some simulants, i.e. di-isopropyl methyl phosphonate (DIMP), diethyl methylphosphonate (DEMP), and triethyl phosphate (TEP) were developed, containing possible molecular and radical pathways. The importance of unimolecular pericyclic decomposition led to evaluate precisely the rate constants of these reactions with high level theoretical calculations. The QCISD(T)/cc-PV∞QZ//B2PLYPD3/6-311+G(2d,d,p) level of theory was selected after a benchmark. The contribution of hindered rotors was included with the 1D-HR-U approach. Tunneling was taken into account for H-atom transfer. Transition state theory was used to calculate high-pressure limit rate constants and pressure dependent rate constants were calculated using Master Equation modelling. The model was validated against experimental pyrolysis and oxidation experimental data available in literature. Flux analyses showed that whatever the conditions are, the first step of decomposition of the studied phosphorus compounds are pericyclic eliminations leading to successive decompositions, whereas bondbreaking or H-atom abstraction remain negligible, even at high temperature.

1H-Phenalen-1-one is a very efficient and easy-to-synthesize photosensitizer. Many substitutions have been previously described, but most of them significantly reduce the singlet oxygen quantum yield. The chloromethyl derivative described elsewhere is a good starting point for the synthesis of many useful derivatives because of the methylene bridge that saves its unique photosensitizing properties. Eighteen new phenalenone derivatives have been synthesized, bearing amine, carboxylic acid, alcohol, azide, and other major functional groups in organic chemistry. These reactions were carried out in good-to-excellent yields, and most of these new compounds retained the singlet oxygen quantum yield of the parent molecule. These new derivatives are very promising precursors for a number of applications such as the development of photosensitive antimicrobial agents or materials.

International audience; A side effect of high level waste vitrification at 1100°C is the volatilization of radioactive cesium (Cs), recaptured further on in the process as a solid aerosol by a dust scrubber. Feedback from industry suggests that Cs combines with technetium (Tc) █ simulated here by rhenium (Re), chosen for its similar behavior █ to form volatile species. This work characterized Cs volatilization and aerosol formation. The first experiment involved elaborating and analyzing a simplified glass enriched with Cs and Re, which reinforce the volatilization phenomena. The results showed that a demixed liquid phase rich in Cs, Re, Mo, and Na formed in the liquid melt, which is reminiscent of a molybdic phase evoked in the literature. Moreover, analyzing the condensed gases led to the conclusion that the alkalis and Re volatilize congruently at around 700°C. In the second experiment, a series of measurements of the gas phase characterized aerosols throughout the process. The size distribution results showed that the particles formed in the furnace were mostly submicronic, and that the aerosols in the calciner and the dust scrubber included nanoparticles and micronic particles. SEM-EDS characterization revealed the composition of a spherical particle from the furnace made of two nested phases: one rich in Cs-Re-O, and the other rich in Na-Mo-O. The analyses performed showed that Cs and Re could be found in every particle sampled throughout the process, and that the micronic particles might originate from the aggregation of submicronic particles because of composition similarities. Thus, the observations led to a better understanding of the behavior of the elements of interest in both the melt and the gas phase.

International audience; Beta-nicotinamide adenine dinucleotide (NAD + /NADH) is an important enzymatic co-factor that can be efficiently regenerated using a rhodium-based catalyst as electron transfer mediator (i.e. [Cp*Rh(bpy)Cl] + , where Cp* = pentamethylcyclopentadienyl and bpy = 2,2-bipyridine). Here, the above mediated regeneration of NADH is implemented in a redox flow bioreactor hybridized with a gas diffusion electrode for hydrogen oxidation. The reactor was initially optimized with respect to rhodium complex and NAD + concentrations, humidification of the hydrogen gas, flow rates of both H 2 gas and electrolytic solution, and solution pH. The integration of an enzymatic reaction consuming the generated NADH was then investigated in a flow process, combining in series the electrochemical reactor to a biochemical cell with immobilized L-lactic dehydrogenase for the conversion of pyruvate to lactate. A high activity was achieved with a turnover number up to 370 h-1 for NADH regeneration. Coupled electrochemical regeneration to enzymatic reaction led to total turnover number values of 2000 and 6.3*10 6 for NADH electrochemical regeneration and bioconversion, respectively.

International audience; In the context of better understanding pollutant formation from internal combustion engines, new experimental speciation data were obtained in a high-pressure jet-stirred reactor for the oxidation of three molecules, which are considered in surrogates of Diesel fuel, n-heptane, ethylbenzene, n-butylbenzene. These experiments were performed at pressures up to 10 bar, at temperatures ranging from 500 to 1100 K and for a residence time of 2 s. Based on results previously obtained close to atmospheric pressure for the same molecules, the pressure effect on fuel conversion and product selectivity was discussed. In addition, for the three fuels, the experimental temperature dependence of species mole fractions were compared with simulations using recent literature models with generally a good agreement. For n-heptane, the obtained experimental data, at 10 bar for stoichiometric mixtures, included the temperature dependence of the mole fractions of the reactants and those of 21 products. Interestingly, the formation of species previously identified as C7 diones was found significantly enhanced at 10 bar compared to lower pressures. The oxidation of ethyl-and n-butylbenzene was investigated at 10 bar for equivalence ratios of 0.5, 1 and 2. The obtained experimental data included the temperature dependence of the mole fractions of the reactants and those of 13 products for the C8 fuels and of 19 products for the C10 one. For ethylbenzene under stoichiometric conditions, the pressure dependence (from 1 to 10 bar) of species mole fraction was also recorded and compared with simulations with more deviations obtained than for temperature dependence. For both aromatic reactants, a flow rate analysis was used to discuss the main pressure influence on product selectivities.

International audience; This purpose of this review is to provide a short overview of electrochemical reduction processes for oxidized contaminants in water. The major parameters affecting the electro-reduction mechanisms and the impact of electrode choice are discussed with reference to both inorganic and organic pollutants that are either regulated or emerging (e.g., non-metal oxyanions, per-and polyfluoroalkyl substances (PFAS)). To conclude, a discussion is presented on the future directions and challenges that must be addressed to develop these electrochemical reduction processes at a larger, commercialized scale.

International audience; 3-Carene is an important potential biofuel with properties similar to the jet-propellant JP-10. Its thermal decomposition and combustion behavior is to date unknown, which is essential to assess its quality as a fuel. A combined experimental and kinetic modeling study has been conducted to understand the initial decomposition of 3-carene. The pyrolysis of 3-carene was investigated in a jet-stirred quartz reactor at atmospheric pressure, at temperatures varying from 650 to 1050 K, covering the complete conversion range. The decomposition of 3-carene was observed to start around 800 K, and it is almost complete at 970 K. Online gas chromatography shows that primarily aromatics are generated which suggests that 3-carene is not a good fuel candidate. The potential energy surface for the initial decomposition pathways determined by KinBot shows that a hydrogen elimination reaction dominates, giving primarily cara-2,4-diene. Next to this molecular pathway, radical pathways lead to aromatics via ring opening. The kinetic model was automatically generated with Genesys and consists of 2565 species and 9331 reactions. New quantum chemical calculations at the CBS-QB3 level of theory were needed to calculate rate coefficients and thermodynamic properties relevant for the primary decomposition of 3-carene. Both the conversion of 3-carene and the yields of the primary products (ie, benzene and hydrogen gas) are well predicted with this kinetic model. Rate of production analyses shows that the dominant pathways to convert 3-carene are hydrogen elimination reaction and radical chemistry.

The present work focusses on measuring the permeability across gas diffusion layers (GDLs) first in a dedicated cell and later in PEM fuel cell configuration with varying bi-polar plate designs. Eight carbon paper-based GDLs with and without the microporous layer (MPL), have been tested. An in-house designed dedicated cell allowed measuring pressure drop depending on flow rate, for i) through-plane and ii) in-plane direction. Further, transport measurements were conducted in 25 cm2 bi-polar plates (BPs) in fuel cell configuration having single or multiple serpentine channels, by stacking the GDL inside. The results show that gas permeability in the dedicated cell for through-plane and in-plane can be estimated by using Darcy's law. However, for BPs, the flow is affected additionally by inertial contribution (Darcy-Forchheimer). Finally, the efficiency allowed by selected GDLs installed in a fuel cell under operation shows a relationship between the equivalent permeability and the fuel cell performance.

International audience; The influence of the mixer shape on the stereoselectivity was measured for lithium–bromine exchange on a gem-dibromoalkene followed by proton trapping. Sixteen passive mixers with eight different angles (135, 120, and 105° (Y mixers); 90° (T mixer); 75, 60, 45, and 30° (W mixers)) and two internal diameters (500 and 250 μm) associated with a tubular microflow reactor having an internal diameter of 500 μm were used. The 45° W-shaped mixer with a smaller internal diameter gave the best selectivity for the monobrominated E product over a range of flow rates without the usual cryogenic conditions (20 °C). With methyl benzoylformate as the electrophile, the corresponding polyfunctionalized product was obtained in a space-time yield of 81 kg L–1 h–1.

Mass transfer phenomena in membrane fuel cells are complex and diversified because of the presence of complex transport pathways including porous media of very different pore sizes and possible formation of liquid water. Electrochemical impedance spectroscopy, although allowing valuable information on ohmic phenomena, charge transfer and mass transfer phenomena, may nevertheless appear insufficient below 1 Hz. Use of another variable, that is, back pressure, as an excitation variable for electrochemical pressure impedance spectroscopy is shown here a promising tool for investigations and diagnosis of fuel cells.

Designing and manufacturing multifunctional nanoparticles (NPs) are of considerable interest for both academic and industrial research. Among NPs used in this field, iron oxide NPs show low toxicity compared to metallic ones and are thus of high interest for biomedical applications. In this work, superparamagnetic Fe3−δO4-based core/shell NPs were successfully prepared and characterized by the combination of different techniques, and their physical properties were investigated. We demonstrate the efficiency of the layer-by-layer process to graft polyelectrolytes on the surface of iron oxide NPs. The influence of the polyelectrolyte chain configuration on the magnetic properties of the Fe3−δO4/polymer core/shell NPs was enlightened. The simple and fast process described in this work is efficient for the grafting of polyelectrolytes from surfaces, and thus, derived Fe3−δO4 NPs display both the physical properties of the core and of the macromolecular shell. Finally, the cytotoxicity toward the human THP-1 monocytic cell line of the core/shell NPs was assessed. The results showed that the polymer-capped Fe3−δO4 NPs exhibited almost no toxicity after 24 h of exposure at concentrations up to 25 μg mL–1. Our results show that these smart superparamagnetic nanocarriers with stealth properties are promising for applications in multimodal cancer therapy, including drug delivery.

Cellulose contains abundant oxygen-containing functional groups and can be used to fabricate hydrogel matrixes for supercapacitors (SCs). However, conventional bacterial cellulose-based SCs need a ...

This work presents the first preparation using the Solution Precursor Plasma Spray process of heterostructured films associating ZnO nanorods (NRs) and various metal oxides (CuO, Fe2O3 and Co3O4) by Solution Precursor Plasma Spray process. These CuO/ZnO, Fe2O3/ZnO and Co3O4/ZnO films exhibit hierarchically chocolate sticks-like, dandelion-like or chrysanthemum-like surface morphologies. These heterostructures were confirmed by SEM, XRD, EDS and Raman analyses. The bandgaps of heterostructured films are narrower than that of pure ZnO. The CuO/ZnO film exhibits the highest photocatalytic activity both under UV and visible light irradiation for the degradation of the Orange II dye due to the homogenous distribution of CuO at the surface of ZnO. The high photocatalytic performances originate from the increased visible light absorption and from the effective separation of charge carriers in CuO/ZnO films compared to ZnO NRs.

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International audience; The Rhamnus alaternus plant is a rich source of excellent bioactive compounds including polyphenols and flavonoids. Yet, the improvement of the extraction yield of total polyphenol content (TPC) and total flavonoid content (TFC) from this plant has never been inspected in depth. Hence, using a 15-run Box-Behnken design, a dynamic maceration process was optimized for the extraction of TPC and TFC in order to investigate the antioxidant capacity of the various fractions by DPPH assay. Three factors (i.e., ratio of solvent-to-solid material plant, stirring speed and extraction time), were investigated and optimized for establishing a cost-effective process in order to produce extracts rich in phenolic components. With a desirability value of 0.970, the optimal extraction parameters of polyphenols and flavonoids were as follows: a ratio of solvent-to-solid of 10:1 mL/g, a stirring speed of 518 rpm, and 24 h of extraction. For such optimized conditions of dynamic maceration, the highest total polyphenols and total flavonoids contents were experimentally determined at 230.9 mg GAE/g and 121.1 mg QE/g of extract, respectively with an IC50 value of 22.5 μg/mL, and were in agreement with the obtained model values.

Titanium-based metal-organic framework (Ti-MOF) is part of the MOF family and has attracted much interest for its unique structural features. Some Ti-based MOFs are difficult to crystallize during the synthesis process; hence only limited studies have been reported. Moreover, the fundamental of Ti-MOF has received less attention, which is crucial to the provision of scientific information for customizing Ti-MOF with suitable properties for practical applications. Thus, this review highlights the Ti-based MOF structure and subsequently summarizes the discovery and development of ever-emerging MIL-125 as advanced materials with multifunctional properties. MIL-125 is a Ti-based MOF derived from Ti metal ions and carboxylate organic ligands. Different modification strategies have been outlined, such as functionalizing with ligands, modifying with metal ions, or incorporating other materials. The versatility and flexibility of MIL-125 elevate its prospects in photocatalytic applications, such as photodegradation of water pollutants, water splitting, and photoreduction of CO2. Finally, the future perspectives were presented at the end of this review to provide beneficial information aiming to expand the capability of MIL-125 in advanced chemistry and materials.

International audience; Three complementary Kraft lignins and a Soda lignin were characterized by NMR (31P, 13C, and HSQC) and GPC. Their theoretical yield in monomers (TMY) assuming a complete cleavage of all β-O-4 linkages was calculated based on these analyses. The most recalcitrant Kraft lignin according to the TMY criteria was depolymerized in supercritical ethanol (250 °C, H2, 110 bar) with Pt/C, Ni/C, and Ru/C catalysts. All catalysts present an important effect on monomers (analyzed by GC/MS), oligomers (by UV fluorescence), and char yields. They promote cracking reactions and the stabilization of the broken bonds by H-transfers. The hydrogenation of the side chains of the monomers is also promoted to notably produce propyl-guaiacol. We show that an oligomeric pool prevails for all catalysts. Then, the effect of lignin structure on the depolymerization mechanism was studied by comparing the 4 lignins with the least precious catalyst (Ni/C). The S/G ratio of monomers is well related to the S/G ratio of lignins. Under our conditions, the β-O-4 content and the TMY do not control the yields in monomers. They are not relevant indicators for the depolymerization of these recalcitrant technical lignins. Future work should focus on novel catalysts and processes to improve the selective conversion of C–C bonds if monomers remain the targeted product.

International audience; In this work, the influence of the stoichiometry of LaxFeOy films on their activity for H2 production by photoelectrochemical (PEC) water splitting was investigated. Thin LaxFeOy films were deposited on electrodes by magnetron co-sputtering and their composition was controlled by adjusting the power applied on metallic iron and lanthanum targets. The highest photoactivity was observed for La0.43FeOy films. The crystallization of these films and their photocatalytic activity were further improved by oxidation in an external furnace at 650 °C for 2 h. Transmission electron microscopy (TEM) analyses confirm the formation of LaFeO3 crystallites in the film and show a thin continuous polycrystalline Fe2O3 layer at the surface. The presence of Fe2O3 at the upper surface originates from an exsolution mechanism typically observed for non-stoichiometric perovskites. The improvement of the photocatalytic properties by adjusting the stoichiometry, the oxidation temperature and the film thickness was confirmed by H2 production measurements performed by mass spectrometry. We observe a large increase in H2 production rate (103%) by comparison with a stoichiometric LaFeO3 thin film. The improvement in catalytic performances for these non-stoichiometric films composed of earth abundant, low-cost and non-toxic elements, make them of high interest materials for photoelectrodes in PEC water splitting systems.

Membrane contactors offer promising performances for the intensification of gas liquid absorption processes. Impressive volume reduction factors compared to packed columns have been reported, mostly for absorption in chemical solvents (e.g. CO2 post combustion capture with MEA). A very limited number of studies addressed however the potentialities of membrane contactors for physical absorption processes. Moreover, the interplay between volume reduction and energy requirement, which is expected to be of major importance for physical solvents, is unexplored. In this study, a systematic parametric analysis of the intensification and specific energy requirement of membrane contactors for CO2 absorption in 5 different physical solvents is reported. The best flow configuration, module packing fraction and membrane properties (mass transfer performances) are identified for the different solvents. Very high intensification factors compared to the baseline technology (i.e. packed column) are shown to be potentially achievable.

International audience; The neutralisation of a simulant of the chemical warfare agent VX (PhX) occurs selectively with lithium ethanolate under classic flow conditions but with moderate reproducibility. Transposed in a custom printed flow reactor, simply feeded with an ethanolic solution of PhX, the formation of EtOLi and the neutralisation are performed in a single operation. Robustness and recyclability of the device is also demonstrated.

The rigorous description of adsorption isotherms of gases or vapors on solids is of major interest for analytical methods such as chromatography and adsorbent-based separation processes (e.g., PSA)...

The VOC removal from air is a major concern both in the context of occupational and domestic exposure. Membrane processes are often presented as unsuitable for the removal of low concentrated VOCs mainly due to a too low driving force leading to high-energy costs. The aim of the work presented in this paper is to investigate the original combination of a dense membrane separation process and a photocatalytic oxidation process implemented in the permeate compartment of the system for the intensification of the separation and the decomposition of toxic compounds. An unpublished modeling of this coupled processes completed by a robust experimental study integrating the main operating parameters (flow rates, pressures, membrane materials, catalyst mass, concentration, light irradiance) is presented in this work. This exploratory study shows that for a test compound, n-hexane, this approach significantly intensifies the separation of a low-concentration VOC (i.e. 1 to 25 ppm) with a low-energy cost. The model developed here allows designing more enhanced system such as hybrid plug-flow module operating with a thin polydimethylsiloxane membrane and sweep-gas on the permeate compartment. This configuration seems particularly relevant for an efficient VOC separation and limits greatly the presence of potential by-products in the treated effluent, such as formaldehyde, acetaldehyde or carbon monoxide well-known intermediates identified in photocatalysis. From a reaction position, this hybrid process leads to the VOC photocatalytic oxidation advantageously increased compared to a single plug-flow reactor especially for low light irradiances (≈3 W m−2). This process is suitable to work with the solar irradiance.

Carbon monoliths were tested as electrodes for vanadium redox batteries. The materials were synthesised by a hard-templating route, employing sucrose as carbon precursor and sodium chloride crystals as the hard template. For the preparation process, both sucrose and sodium chloride were ball-milled together and molten into a paste which was hot-pressed to achieve polycondensation of sucrose into a hard monolith. The resultant material was pyrolysed in nitrogen at 750 ◦C, and then washed to remove the salt by dissolving it in water. Once the porosity was opened, a second pyrolysis step at 900 ◦C was performed for the complete conversion of the materials into carbon. The products were next characterised in terms of textural properties and composition. Changes in porosity, obtained by varying the proportions of sucrose to sodium chloride in the initial mixture, were correlated with the electrochemical performances of the samples, and a good agreement between capacitive response and microporosity was indeed observed highlighted by an increase in the cyclic voltammetry curve area when the SBET increased. In contrast, the reversibility of vanadium redox reactions measured as a function of the difference between reduction and oxidation potentials was correlated with the accessibility of the active vanadium species to the carbon surface, i.e., was correlated with the macroporosity. The latter was a critical parameter for understanding the differences of energy and voltage efficiencies among the materials, those with larger macropore volumes having the higher efficiencies. This work was supported by ICEEL and Region Grand Est and J.F.V.-V. was hired with these fundings. This work was partly supported by a grant overseen by the French National Research Agency (Pc2TES ANR-16-CE06-0012-01), and the authors involved in it (AC, BK and VF) acknowledge the support of the project's coordinator, Mrs Fouzia Achchaq. This study was partly supported by TALiSMAN project (2019-000214), funded by European Regional Development Fund (ERDF).

The relationship between interfacial and bulk emulsion viscoelasticity is investigated. Water-in-dodecane reverse Pickering emulsions, with a dispersed phase volume fraction of 0.66, stabilized with partially hydrophobic silica particles are addressed. Interfacial and bulk viscoelastic properties are probed via 2D and 3D oscillatory shear rheology. The silica particles concentration and NaCl content have been varied. In the whole range of concentrations studied the elastic modulus (G′) remains always greater than the viscous modulus for 2D and 3D rheology. The viscoelastic behavior can be related to the silica concentration both at the interface and in the emulsion. Power law dependences towards the silica content are recorded for the interfacial and the bulk emulsion elastic modulus. When increasing the NaCl concentration, the viscoelastic properties both at the interface and in the emulsion become stronger. The amount of silica and NaCl produces similar effects on both the interface and bulk viscoelastic properties. The increase of their concentration induces a rigidification of the dodecane/water interface since G P ′ (interface) increases. Such interfacial hardening produces a rigidification of the droplets ( G P ′ (Emulsion) is enhanced). Correlations between the interfacial and bulk emulsion viscoelasticity are also extracted from the experimental data. This is the first time that these kinds of relationship are reported. These results highlight that everything that affects the interfacial viscoelasticity is reflected on the bulk scale of emulsions.

In this study, phenolic compounds from an aqueous protein by-product from rapeseed meal (RSM) were identified by HPLC-DAD and HPLC-ESI-MS, including sinapine, sinapic acid, sinapoyl glucose, and 1,2-di-sinapoyl gentibiose. The main phenolic compound in this by-product was sinapine. We also performed acid hydrolysis to convert sinapine, and sinapic acid derivatives present in the permeate, to sinapic acid. The adsorption of phenolic compounds was investigated using five macroporous resins, including XAD4, XAD7, XAD16, XAD1180, and HP20. Among them, XAD16 showed the highest total phenolic contents adsorption capacities. The adsorption behavior of phenolic compounds was described by pseudo-second-order and Langmuir models. Moreover, thermodynamics tests demonstrated that the adsorption process of phenolic compounds was exothermic and spontaneous. The highest desorption ratio was obtained with 30% (v/v) and 70% (v/v) ethanol for sinapine and sinapic acid, respectively, with a desorption ratio of 63.19 ± 0.03% and 94.68 ± 0.013%. DPPH and ABTS tests revealed that the antioxidant activity of the hydrolyzed fraction was higher than the non-hydrolyzed fraction and higher than the one of vitamin C. Antioxidant tests demonstrated that these phenolic compounds could be used as natural antioxidants, which can be applied in the food industry.

International audience; Correlation of the mass transfer characteristics of microfluidic parallel-plate electrochemical reactors is proposed for the first time. Firstly, the variation in the mass transfer coefficient (k m) (1.61-3.94 × 10 − 5 m s − 1) over a wide range of interelectrode distances (d elec) from millimetric (3 mm) to micrometric values (100 µm) is reported. Secondly, a drastic slope change in the curve makes it possible to identify the onset of microfluidic behavior in a quantitative way for the first time, i.e. below a 1000 µm gap. Thirdly, a mathematical model is proposed which predicts k m for any d elec of interest. Fourthly, under laminar flow (7 < Reynolds (Re) < 623) and for temperatures in the range of 10-50 • C (532 < Schmidt (Sc) < 3315), new Sherwood (Sh) correlations are obtained for both microfluidic and millimetric configurations. It is thus feasible to extrapolate k m for microfluidic electrochemical reactor scale-up.

International audience; Chemical Product Engineering (CPE) is marked by numerous challenges, such as the complexity of the properties–structure–ingredients–process relationship of the different products and the necessity to discover and develop constantly and quickly new molecules and materials with tailor-made properties. In recent years, artificial intelligence (AI) and machine learning (ML) methods have gained increasing attention due to their performance in tackling particularly complex problems in various areas, such as computer vision and natural language processing. As such, they present a specific interest in addressing the complex challenges of CPE. This article provides an updated review of the state of the art regarding the implementation of ML techniques in different types of CPE problems with a particular focus on four specific domains, namely the design and discovery of new molecules and materials, the modeling of processes, the prediction of chemical reactions/retrosynthesis and the support for sensorial analysis. This review is further completed by general guidelines for the selection of an appropriate ML technique given the characteristics of each problem and by a critical discussion of several key issues associated with the development of ML modeling approaches. Accordingly, this paper may serve both the experienced researcher in the fieldas well as the newcomer.

International audience; Metal-chelating peptides (MCP) are considered as indirect antioxidants due to their capacity to inhibit radical chain reaction and oxidation. Here, we propose a new proof of concept for the screening of MCPs present in protein hydrolysates for valorizing their antioxidant properties by using the emerging time-resolved molecular dynamics technology, switchSENSE. This method unveils possible interactions between MCPs and immobilized nickel ions using fluorescence and electro-switchable DNA chips. The switchSENSE method was first set up on synthetic peptides known for their metal-chelating properties. Then, it was applied to soy and tilapia viscera protein hydrolysates. Their Cu2+-chelation capacity was, in addition, determined by UV-visible spectrophotometry as a reference method. The switchSENSE method has displayed a high sensitivity to evidence the presence of MCPs in both hydrolysates. Hence, we demonstrate for the first time that this newly introduced technology is a convenient methodology to screen protein hydrolysates in order to determine the presence of MCPs before launching time-consuming separations.

International audience; It is presented for the first time the occurrence and modelling of cathodic mineral electro-precipitation in microfluidic thin-film configuration of electrochemical advanced oxidation process (EAOP), in order to better understand and predict the cathode's scaling when treating water containing Mg2+ and Ca2+. Upon a systematic study, the main results show that when an inter-electrode distance of 500 µm is used at 4 mA cm−2, local alkalization on cathode surface occurs despite the absence of dissolved O2 suggesting that it takes place due predominantly to water reduction (current efficiency > 99%) and not dissolved O2 reduction. Moreover, electromigration phenomenon could be neglected when varying ionic strength from 0.02 to 0.1 mol L−1, while diffusion was the kinetic rate-limiting step. In addition, Ca(OH)2 and MgCO3 precipitates were not formed under all investigated conditions. Mg(OH)2 electro-precipitation was found to be highly dependent on current density, but independent of other ionic species jointly present in electrolyte. Mg(OH)2 precipitated once interfacial pH of 10.2 was reached. More CaCO3 was electro-precipitated at lower current density (ca. 7.2%) owing to more vigorous gas evolution when higher current density was applied. 12% less CaCO3 electro-precipitation was found in the presence of Mg2+ confirming its inhibiting effect towards CaCO3 scaling. The mathematical model proposed could fit well the experimental curves (Root mean square error (RMSE) < 0.1163) and permit to predict the evolution of concentration of depositing species (i.e. Mg2+, Ca2+ and CO32−). Furthermore, the role of hydroxyl radicals (•OH) produced at boron-doped diamond (BDD) anode could be neglected upon the applied conditions, meaning that the outcome of this study is reliable across all types of water containing Mg2+, Ca2+ and/or CO32− in compliance to their ubiquity when it is to be treated by electrolysis in general

International audience

The chemistry underlying liquid-phase oxidation of organic compounds, the main cause of their aging, is characterized by a free-radical chain reaction mechanism. The rigorous simulation of these phenomena requires the use of detailed kinetic models that contain thousands of species and reactions. The development of such models for the liquid phase remains a challenge as solvent-dependent thermokinetic parameters have to be provided for all the species and reactions of the model. Therefore, accurate and high-throughput methods to generate these data are required. In this work, we propose new methods to generate these data, and we apply them for the development of a detailed chemical kinetic model for n-butane autoxidation, which is then validated against literature data. Our approach for model development is based on the work of Jalan et al. [J. Phys. Chem. B 2013, 117, 2955-2970] who used Gibbs free energies of solvation [ΔsolvG(T)] to correct the data of the gas-phase kinetic model. In our approach, an equation of state (EoS) is used to compute ΔsolvG as a function of temperature for all the chemical species in the mechanism. Currently, ΔsolvG(T) of free radicals cannot be computed with an EoS and it was calculated for their parent molecule (H-atom added on the radical site). Theoretical calculations with the implicit solvent model were performed to quantify the impact of this assumption and showed that it is acceptable for radicals in n-butane and probably in all n-alkanes. New rate rules were proposed for the most important reactions of the model, based on theoretical calculations and the literature data. The developed detailed kinetic model for n-butane autoxidation is the first proposed model in the literature and was validated against the experimental data from the literature. Simulations showed that the main autoxidation products, sec-butyl hydroperoxides and 2-butanol, are produced from H-abstractions from n-butane by sec-C4H9OO radicals and the C4H9OO + C4H9OO reaction, respectively. The uncertainty of the product ratio ("butanone + 2-butanol"/"2-butoxy + 2-butoxy") of the latter reaction remains high in the literature, and our simulations suggest a 1:1 ratio in n-butane solvent.

Curcumin is a naturally occurring hydrophobic polyphenol compound. It exhibits a wide range of biological activities such as antibacterial, anti-inflammatory, anti-carcinogenic, antifungal, anti-HIV, and antimicrobial activity. In this research work, antimicrobial curcumin nanofibrous membranes are produce by an electrospinning technique using the Eudragit RS 100 (C19H34ClNO6) polymer solution enriched with curcumin. The morphology and chemistry of the membrane are analyzed using scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Kirby Bauer disk diffusion tests are carried out to examine the antibacterial effectiveness of the membrane. Experimental results show that the nanofibers produced are of uniform thickness morphology and curcumin is successfully incorporated into the nanofibrous mat, while no chemical bonding was observed between curcumin and the polymer. The antimicrobial curcumin nanofibrous membranes can be effectively applied as antimicrobial barrier in a wide variety of medical applications such as wound healing, scaffolds, and tissue engineering.

International audience; This work aims at studying the expanding and breakup dynamics of the thread of a controllable dispersed phase under different flow rates in a microfluidic flow-focusing device. The whole formation process of ferrofluid droplets under no magnetic field (NM), a radial magnetic field (RM) and an axial magnetic field (AM) were investigated and compared. It was found that the volume of the ferrofluid droplets can be actively controlled by the applied magnetic field. The radial magnetic field and axial magnetic field affect mainly the expanding and breakup processes of the thread, respectively. The influence of the flow rates, magnetic flux density and magnetic field direction on the formation and breakup processes were extensively studied. The variation of the minimum width of the ferrofluid thread with the remaining time could be scaled with a power law.

International audience; The efficient, versatile and straightforward synthesis of the first N-alkyl analogs of induline 3B (8a and 8b) is reported. Thanks to the introduction of lipophilic substituents and its attractive photophysical properties (far-red emission and production of singlet oxygen), phenazinium 8b can be used as theranostic agent and shows, at very low concentration (100 nM), a remarkable ability to: i) image cells and zebrafish embryos with high quality under both mono (514 nm) and biphotonic (790 and 810 nm) excitations, ii) efficiently and quickly penetrate cancer cells rather than healthy fibroblast, iii) induce a total or almost total cancer cell death in vitro and in vivo after illumination (exc = 540-560 nm). The molecular structure of 8b is based on a triamino-phenazinium core only, with no need for additional components, highlighting the emergence of a minimalistic and versatile class of fluorescent probes for targeted photodynamic cancer therapy.