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This article aims to study the interest of spent coffee grounds (SCG) valorization through caffeine recovery. In an original way, this study takes into account all the parameters such as (i) the brewing coffee methods (household, coffee shops, etc.), (ii) the storage conditions, in particular the drying step, (iii) the solid/liquid extraction parameters such as the nature of solvent, the temperature, the extraction time and the solid/liquid ratio, and (iv) the liquid/liquid purification parameters such as the nature, the volume and the pH of extraction medium. Results have shown that spent coffee grounds from coffee-shops obtained by percolation contain a higher amount of caffeine than spent coffee grounds from households obtained from spent pods or filters. A drying treatment is not required when extraction is performed under one week after the spent coffee grounds collection with 96.4% of not degraded caffeine. Solid/liquid extraction performed with 25 mL.g−1SCG of hydroalcoholic solvent (water/EtOH, v/v 60/40) at 60 °C during 15 min have given a caffeine yield up to 4.67 mg.g−1SCG. When using ethyl acetate, 93.4% of the caffeine has been selectively recovered by liquid/liquid extraction. Finally, the extraction of caffeine for the valorization of spent coffee grounds is a promising and easy way, which fits with an already important and well established market.

The single extraction of rhenium(VII) and uranium(VI) from nitric acid solution by dicyclohexano-18-crown-6 (DCH) solutions was investigated. The extraction of Re(VII), in the form of perrhenate (ReO4−) anion, was optimum for a nitric acid concentration of 3 M and was explained by the ion-pair extraction of perrhenate anions by the hydroxonium DCH complex. The stoichiometry of the Re(VII) complex was obtained from the distribution data by slope analysis and the extracted specie was identified as {ReO4−(DCH-H3O)+}. The uranyl extraction by DCH solutions was evaluated under the same conditions and the extracted specie was identified as {(NO3−)2(DCH-UO22+)} for a nitric acid concentration above 5 M. The extraction of rhenium(VII) from nitric acid solution by DCH solutions in the presence of large excess of uranium(VI) was then investigated. For a nitric acid concentration of 3 mol/L, the extraction efficiency of perrhenate was found to be almost independent of uranium concentration. Based on the chemical similarities between Re(VII) and Tc(VII), this suggests that DCH could be considered for the separation of technetium (VII)/uranium(VI) from nitric acid solution.

International audience; The identification of the intermediates and by-products produced during the oxidative cleavage of cycloalkenes in the presence of H2O2 and a tungsten-based catalyst for the production of dicarboxylic acids has been carried out under various experimental conditions. On the basis of this mechanistic investigation and previous studies from the literature, a complete reaction scheme for the formation of the reaction products and by-products is proposed. In this hypothetical mechanism, the production of a hydroperoxyalcohol intermediate accounts for the two pathways proposed by Noyori and Venturello for the formation of the targeted dicarboxylic acid. In addition, Baeyer–Villiger oxidation of the mono-aldehyde intermediate allows explaining the formation of short chain diacids observed as by-products during the reaction. Hence, the proposed mechanism constitutes a real tool for scientists looking for a better understanding and those heading to set up environmentally friendly conditions for the oxidative cleavage of cycloalkenes.

International audience; This review aims to establish the state of the art of the existing literature on the valorization of coffee and coffee by-products (i.e. green coffee, coffee husk, pulp, silverskin and spent coffee grounds) through the use of pressurized fluids as solvents, including subcritical water (SCW) and supercritical carbon dioxide (SC-CO2). The first part reviews the exploitation, the composition, the properties and the ways of valorization of coffee beans and their by-products, highlighting their high potential as raw material. The second part is dedicated to subcritical H2O and supercritical CO2 applied to coffee and coffee by-products valorization, discussing the involved mechanisms, the parameters’ influence and the superiority of subcritical H2O and supercritical CO2 in comparison to other solvents and techniques. Indeed, subcritical H2O is considered as a super solvent, catalyst and reagent at the same time, being the most efficient technology for carbohydrate and polyphenol recovery as well as biocrude-oil production. Supercritical CO2 is considered as a chameleon solvent, with unlimited tunability, able to selectively extract high value molecules but also compete with organic solvents in amount and quality of the produced extract. In addition, subcritical H2O and supercritical CO2 are complementary solvents, targeting together all the types of molecules in coffee and coffee by-products, leading to the development of a Green Solvent Bio-Refinery (GreSBiR) with sequential uses of subcritical H2O and supercritical CO2.

International audience; Viticultural waste has been widely demonstrated to contain high-added value compounds named the stilbenes. Among them, trans-resveratrol (Rsv) and trans-εviniferin (Vf) are the most abundant in particular in grape canes. Various emerging methods such as ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE) or pressurized solvent extraction (PSE) have been studied to recover Rsv and Vf from grape canes in order to enhance their extraction. This paper gives a critical overview of the techniques used to this end, integrating conventional and nonconventional methods investigated in the literature as well as those used in industrial processes. It finally highlights that the unconventional technics are usually less timeconsuming than conventional extraction ones but further investigations for the discussed compounds and biomass are needed to optimize and understand the influence of the individual parameters of each extraction process.

International audience; This last century, the development of new medicinal molecules represents a real breakthrough in terms of humans and animal life expectancy and quality of life. However, this success is tainted by negative environmental consequences. Indeed, the synthesis of drug candidates requires the use of many chemicals, solvents, and processes that are very hazardous, toxic, energy consuming, expensive, and generates a large amount of waste. Many large pharmaceutical companies have thus moved to using green chemistry practices for drug discovery, development, and manufacturing. One of them is the use of energy-efficient activation techniques, such as ultrasound. This review summarizes the latest most representative works published on the use of ultrasound for sustainable bioactive molecules synthesis.

A series of phosphonate-functionalized task-specific ionic liquids (TSILs) have been synthesized and studied for selective extraction of tantalum from a sulfuric acid medium. The results described here show that high distribution coefficient values can be achieved for the selective separation of tantalum (Ta). Such a system can be used as an alternative to TBP for the separation and purification of tantalum by solvent extraction.

International audience; Dicarboxylic acids constitute one of the most important oxygenated intermediates in the chemical industry providing a wide range of daily products: fibers, pharmaceuticals, cosmetics, lubricants, pesticides and plasticizers. A major part of their large-scale production relies on the oxidative cleavage processes of unsaturated acids and cyclic olefins but suffers from severe drawbacks such as the use of harmful compounds, the need of specific set-ups to produce oxidants, expensive catalysts and energy-consuming conditions. In the context of the development of sustainable oxidation reactions, hydrogen peroxide has attracted growing interest thanks to its multiple benefits to replace conventional oxidants: low toxicity, no need of energetic conditions to perform catalytic oxidation and generation of benign H2O as a by-product. The present review aims at bringing a critical view on the development of catalytic systems for the H2O2-mediated oxidative cleavage of cycloalkenes toward green chemistry criteria. Different transition metal-based catalysts investigated for the reaction will be discussed with a special emphasis on tungsten. Next, the performance of different heterogeneous and homogeneous W-based systems on the oxidative cleavage of various cycloolefins will be presented. More specifically, their relevance towards sustainable oxidation will be assessed by studying key reaction features: solvent, H2O2 amount, reaction time and catalyst synthesis, recoverability and activity. The main challenges regarding the oxidative cleavage of medium-sized cycloalkenes with W–H2O2 systems will also be exposed. Finally, the potential of ultrasound as an unconventional activation method will be pointed out to overcome the limits encountered with the conventional thermal heating leading to even more environmentally-friendly cycloalkene oxidative cleavage.

International audience; Viticultural byproducts are known to contain high-value compounds such as stilbenes. The wine sector in Savoie Mont Blanc region (France) generates a great amount of waste, including grape canes and grapevine stocks that remain unvalued. Herein, the potential of the most widespread grapevine varieties in the Savoie Mont Blanc territory, Jacquère and Mondeuse, as sources of two stilbenes, trans-resveratrol (Rsv) and trans-ε-viniferin (Vf), was investigated for the first time. Using the reported extraction technique, the present work focused on several pre-extraction parameters influencing the extraction efficiency, including grapevine variety, age of vines, time of material storage, and particle size of the woody material. This work revealed important Rsv and Vf contents in Jacquère residues of 1681–6124 and 1620–6667 mg·kgdw–1, respectively, whereas for the Mondeuse variety, the targeted molecule yields were 1724–4636 and 1713–5322 mg·kgdw–1, respectively. These results are promising when compared with the well-known high stilbenes levels in Pinot Noir and Gewurztraminer varieties but also highlight a considerable variability depending on the applied pre-extraction parameters.

International audience; Sonoluminescence (SL) spectra of a very dry [BEPip][NTf 2 ] ionic liquid were measured in the first minutes of sonication under Ar. The intense sonoluminescence allowed us to monitor the time-evolution of the SL spectra. Several molecular emissions were observed. Rovibronic temperatures of C 2 and CN were determined giving vibrational temperatures of 5800 AE 500 K and 6000 AE 500 K and rotational temperatures (i.e. translational or gas temperatures) of 4000 AE 500 K. These temperatures stay remarkably constant during the sonolysis, while SL spectra undergo strong changes that illustrate the very fast evolution of the plasma during the first minutes of sonication. The expected strong decrease in the plasma electron energy also reflects in the evolution of the populations of CH electronically excited states. The physical meaning of temperatures derived from molecular emissions in SL spectra is discussed.

The extraction of rare earth elements (REEs) from nitric acid solution with a triphosphine trioxide (TPO) is presented. Performances of such a ligand in ionic liquids vs. a classical solvent (benzyl ether) are compared. TPO seems to be 10 to 100 times more efficient when it is dissolved in ionic media whatever the concentration of nitric acid involved. Mechanistic investigations reveal that cation exchange classically observed in ionic liquids is not consistent with the experimental data. Moreover, clear differences in the TPO/Ln complexes between classical and ionic media are highlighted. A stable complex of 1 lanthanide for 3 TPO is formed in an ionic liquid whereas a complex of 1 lanthanide for 6 to 9 TPO is formed in benzyl ether. Back extraction is also studied and good recovery of REEs could be obtained. The TPO/ionic liquid system shows remarkable performances i.e. efficiency and selectivity towards lanthanides in a simulated leaching solution of a Nd/Fe/B/Dy magnet.

Sonoluminescence (SL) spectra of a very dry [BEPip][NTf

International audience; The use of high frequency ultrasound (800 kHz) highlights the non-radical character of the cis-cyclooctene epoxidation mediated by H2O2 and H2WO4. Combination of moderate mixing brought by the ultrasonic irradiation with precise thermoregulation of the double jacketed sonoreactor demonstrates the potential of this technique for studying and optimizing all the reaction parameters. The results not only reveal that the optimized ultrasonic conditions lead to excellent epoxidation outcomes with 96% yield and 98% selectivity but also to higher selectivities toward the epoxidation product compared with silent conditions.

International audience; A novel family of ketone functionalized task specific ionic liquids (TSILs) was designed for the selective extraction of tantalum from sulfuric acid medium. We report the synthesis of functionalized hydrophobic ionic liquids based on piperidium, imidazolium or pyridinium cations bearing ketone moieties and their application in the liquid/liquid extraction of Ta(V). Recovery processes for Ta after extraction were performed and the recyclability of the TSIL was demonstrated. An eco-friendly process based on a TSIL was proposed for the extraction and stripping of tantalum from sulfuric acidic medium. Such system can be used as an alternative to the methyl-iso-butyl ketone (MIBK) which is the most commonly used extractant for the separation and purification of niobium and tantalum by solvent extraction

The hydrogen peroxide mediated oxidative depolymerization of kraft lignin was investigated in the presence of different metal salt catalysts in acetone/water (1/1 v/v) at low temperature. Na2WO4·2H2O appeared to be the best catalyst, yielding four vanillin-based monomers. Using the optimized conditions, monomers were obtained in 0.51 wt % yield from lignin. This result is among the best depolymerization yield obtained from lignin using hydrogen peroxide mediated oxidation. Optimization of the reaction conditions (temperature, catalyst loading, oxidant amount) revealed that the monomer formation is closely related to the cleavage vs recombination of the intermediates. In addition, the use of ultrasound irradiation involves higher oxidative coupling of phenoxy radicals resulting from lignin polymerization.

Based on our original knowledge and experience on both polychlorinated biphenyls (PCBs) identification in aquatic ecosystems, and use of ionic liquids (ILs) as solvents and/or co-catalysts in green chemistry, we drawn a dared comparison between these two families. Indeed, PCBs has been used during several decades for their new properties, but are now considered as prevalent and persistent pollutants; some toxic effects on environment or human are still revealed. ILs, often designated as “green solvents” are increasingly used in numerous applications, but few studies reported about their environmental impact are still controversial. Through a parallel between properties and applications of PCBs and ILs, we wondered if history could not repeat itself, and how to provide a better future for ILs. Here, we provide some interesting comparisons and we discuss which tracks it could be important to follow for ILs applications in order to avoid the errors done with PCBs.

This work describes an efficient process for the reduction of nitro compounds to the corresponding amines with a catalytic amount of Pd/C (0.6 mol%), and a mixture of sodium hypophosphite and hypophosphorous acid as a reducing agent in H2O/2-MeTHF at 60 °C. The reaction was optimized under silent conditions. The conditions for the in situ production of H2 using the mixture NaH2PO2/H3PO2 were studied. The influence of ultrasonic activation was investigated both in terms of efficiency and kinetics. The reaction was shown to be efficient in water, at 70 °C with a quantitative conversion and a maximal yield in only 15 min thanks to the ultrasonic activation. Finally, ultrasound was proved to act as a physical agent of phase transfer.

Cyclohexanol oxidation to cyclohexanone is an important reaction in both organic chemistry and industry. We propose here an efficient, eco-friendly, and general method for oxidizing five- to eight-membered cyclanols used as model substrates, with aqueous hydrogen peroxide (H2O2) in the presence of tungstic acid (H2WO4) as a catalyst and an ammonium-based ionic liquid (IL) as a co-catalyst under organic solvent-free conditions. Cyclohexanol was found to be the most reactive of the four tested cyclanols. In addition, the role of the IL as a phase transfer catalyst was confirmed by the use of Aliquat 336 and the kinetic of the reaction was significantly improved under microwave or ultrasonic activation, leading to excellent yields in only a few minutes.

Envahissante en Europe, utile en Asie La renouee du Japon a ete repertoriee dans la liste des cent especes exotiques envahissantes (EEE) les plus nefastes au monde publiee par l'ISSG (Invasive Species Specialists Group), la CSE (Commission de la sauve-garde des especes) et l'UICN (Union internationale pour la conservation de la nature) en 2007. Les EEE de cette liste ont ete choisies selon deux criteres : leur impact desastreux sur la diversite biologique et/ou les activites humaines et leur potentiel d'invasions biologiques. Les consequences negatives de la proliferation de la renouee sont diverses et impactent la faune et la flore (perte de biodiversite), la stabilite des berges, le paysage, les activites agricoles et de gestion des territoires (secu-rite, sante, loisirs). En plus des difficultes pour les gestion-naires des territoires qui sont confrontes aux problemes lies a sa proliferation, les renouees asiatiques repre-sentent une source importante de depenses publiques. Une etude menee par le commissariat general du deve-loppement durable sur la periode 2009 a 2013 indiquait un cout moyen de trente-huit millions d'euros annuel en France en considerant les depenses liees au traitement de ces EEE et des dommages qu'elles causent. Pourtant, la renouee du Japon est une plante dont cer-taines parties sont comestibles et qui est cultivee en Asie a la fois pour l'alimentation mais aussi pour ses vertus therapeutiques. Ainsi, en Coree, ses racines peuvent accompagner le riz alors qu'au Japon ses feuilles sont uti-lisees pour faire de la confiture. Ces dernieres annees, les benefices de certains constituants de la renouee du Japon et en particulier de ceux de ses rhizomes font l'objet d'un interet croissant en Europe, pour des applications en phy-totherapie. En effet, de nombreux travaux ont ete realises par des equipes de recherches essentiellement asiatiques en s'inspirant des usages traditionnels et empiriques des plantes, et montrent les multiples activites biologiques de la renouee du Japon. Ainsi, si ses feuilles et racines sont connues pour leurs activites anti-bacterienne et anti-oxydante, ses racines presentent egalement des activites anti-infectieuse, anti-virale, anti-tumorale, anti-inflam-matoire, anti-tyrosinase dermatologique, anti-allergique neuro-protectrice, inhibitrice de l'hypoxanthine oxydase et sur le metabolisme lipidique. A l'heure ou de plus en plus d'agents anti-infectieux allopathiques courants presentent des effets secondaires indesirables et/ou deviennent inefficaces, il est neces-saire d'envisager de nouvelles strategies, notamment en s'inspirant de l'approche des medecines traditionnelles chinoise, ayurvedique ou de la naturopathie. Dans ce contexte, la renouee du Japon est une plante d'une grande richesse en metabolites secondaires potentielle-ment exploitables (encadre ). Sa valorisation permet-trait d'encourager sa coupe et/ou son arrachage et d'ainsi limiter sa proliferation, tout en reduisant les couts des traitements dont elle est actuellement responsable. Les techniques d'eradication des renouees asiatiques consistent en un deterrage precoce, des coupes successives, un criblage-concassage… soit un ensemble de pratiques qui necessite le transport et le stockage de quantites importantes de terres et de dechets potentiellement contamines dans des conditions adaptees mais couteuses. La solution alternative proposee ici est de valoriser les rhizomes de renouees riches en molecules d'interet, pour les secteurs du cosmetique, des complements alimentaires et de la pharmaceutique.

A novel combination of Fe(TAML)Li and (diacetoxyiodo)benzene for the oxidation of primary and secondary alcohols at 25 °C in acetone is reported. In view of the interesting ability of this system to selectively cleave specific types of C–C bonds of elaborated alcohols, the application of this novel combination to the oxidative cleavage of lignin model molecules was investigated. Considering the numerous supported versions of the oxidant as well as the mild conditions employed, the developed methodology appears to be a promising lignin depolymerization strategy.

Over the past 15 years, sustainable chemistry has emerged as a new paradigm in the development of chemistry. In the field of organic synthesis, green chemistry rhymes with relevant choice of starting materials, atom economy, methodologies that minimize the number of chemical steps, appropriate use of benign solvents and reagents, efficient strategies for product isolation and purification and energy minimization. In that context, unconventional methods, and especially ultrasound, can be a fine addition towards achieving these green requirements. Undoubtedly, sonochemistry is considered as being one of the most promising green chemical methods (Cravotto et al. Catal Commun 63: 2-9, 2015). This review is devoted to the most striking results obtained in green organic sonochemistry between 2006 and 2016. Furthermore, among catalytic transformations, oxidation reactions are the most polluting reactions in the chemical industry; thus, we have focused a part of our review on the very promising catalytic activity of ultrasound for oxidative purposes.

International audience; Energy conversion in sonochemistry is known to be an important factor for understanding the mechanism of chemical reactions. However, ultrasound characteristics are dependent on the physical properties of the liquid medium. This work describes specific heat capacities (cp) of five hydrophobic bis(trifluoromethylsulfonyl)imide based ionic liquids ([C8mpyrr][NTf2], [C4mpyrr][NTf2], [C8epip][NTf2], [C8mim][NTf2], [C8mpy][NTf2]) and, for the first time, the acoustic power when they are submitted to ultrasound at two selected electric powers. The behavior of ultrasound in ionic liquids is then compared to the one in water. Despite the difference in cp values, the measured acoustic powers are very similar for both media. Indeed, ionic liquids heat up faster than water, and this can lead to interesting effects when using ionic liquids as solvents in organic chemistry.

We report template-free electrodeposition of tellurium (Te) 1D nanostructures at moderate temperature (≤100 °C), using a piperidinium-based ionic liquid mixture: 1-ethyl-1-octylpiperidinium bis(trifluoromethylsulfonyl)imide:1-ethyl-1-octylpiperidinium bromide (EOPipTFSI:EOPipBr). Single crystalline nanowires were obtained, with diameter ranging from 30 nm to 200 nm depending on experimental conditions. A preferential growth was observed along the [001] direction. The presence of bromide is necessary for the growth of nanowires. The temperature plays also a major role: the crystallinity of Te nanowires is improved by increasing temperature, whereas more homogeneous size distribution is observed at lower temperature. Keywords: Electrodeposition, Nanowires, Template-free, Tellurium, Ionic liquid

BACKGROUND: Cloud point extraction (CPE) is an attractive alternative to solvent extraction. However, comparisons between both techniques are lacking. In this paper, the extraction of uranium(VI) using 8-hydroxyquinoline (HQ) as chelating agent was studied by CPE using Triton X-114 as non-ionic surfactant and by solvent extraction using CHCl3 as diluent. RESULTS: Using CPE, a quantitative extraction was observed for pH higher than 4.5 with a HQ/U ratio of 10. Using solvent extraction an increase in the HQ/U ratio up to 50 is necessary to obtain a near quantitative extraction. Both extraction systems were then compared with respect to the nature of extracted species, and the extraction constants determined using log-log analysis of the extraction data. In the solvent extraction system, the extracted species were identified as UO2Q2 and the corresponding extraction constant was found to be log kex = − 3.6 ± 0.2 on the molar scale. Considering that UO2Q2 is also the extracted species in CPE, a slightly higher extraction constant, i.e. log kex = − 2.5 ± 0.3, was found. CONCLUSION: Such a small difference in favour of the CPE system may arise from the combination of various phenomena, including effects of temperature and effects of ‘extractant environment’. However, a change in the nature of the extracted species, namely from UO2Q2 in the solvent extraction system to the formation of adducts, i.e. UO2Q2(HQ) and UO2Q2(HQ)2 in the CPE system, due to higher HQ concentration in the surfactant-rich phase compared with chloroform, cannot be precluded, but requires confirmation. Copyright © 2012 Society of Chemical Industry

The now-famous “Miller-Urey experiment” used a reduced mixture of gases to form basic organic molecules, such as amino acids. Since then, several methods have tried to reproduce the synthesis of amino acids under unusual conditions. All authors agree that the formation mechanisms of amino acids under such conditions might be of radical origin. If so, sonochemistry, known to enhance or to promote radical pathways, should be a powerful tool to access the synthesis of these compounds. We explored the feasibility of amino acid synthesis under ultrasonic irradiation in aqueous medium under a reductive atmosphere. The effects of several experimental parameters such as incident ultrasound frequency, temperature, nature and concentration of initial reactants, reaction time, and acoustic energy were explored.

International audience; A new ionic liquid 1-octyl-3,5-dimethylpyridinium iodide ([O35LUT]+[I]−) was synthesized and utilized as coating for an ozone denuder device based on a high-volume aerosol sampler (30 m3 h−1). Particle transmission of the denuder was studied, and over 99% of particles ranging from 10 to 2,500 nm were transmitted. The device, containing 4.66 g of ionic liquid, was used outdoors, under dry and damp atmospheric conditions. In order to expose the device to an average concentration of 120 ppbv (240 µg m−3) of ozone in air, an additional production of ozone was directly injected into the denuder. Under these conditions, over 97% of ozone was removed for approximately 120 h (5 days). Therefore, iodide-based ionic liquids can be used as a new alternative to conventional denuder coatings in order to reduce artifacts occurring during sampling of particulate matter. Future applications are not limited to ozone removal for specific aerosol sampling methods.

The cis-syn-cis isomer of dicyclohexano-18-crown-6 (DCH18C6) has been shown to be an efficient extractant able to perform the separation of Pu(IV) and U(VI) from fission products and then the separation of Pu(IV) from U(VI) without valence exchange as required in the PUREX process. This macrocycle was irradiated in nitric acid with a 137Cs γ source to study its radiation chemical stability. Radiation chemical yields (G) were determined by gas chromatography. The results show that the presence of uranyl nitrate has a strong influence on DCH18C6 radiation chemical stability. Indeed, the presence of this template ion increases the macrocycle stability by promoting fragments recombination.

A procedure for the selective removal of uranium traces dissolved in drinking water has been studied. Plate module membrane filtration equipment was operated to evaluate the performance and selectivity of three different nanofiltration flat-sheet membranes. Experiments were carried out using various commercial mineral waters with distinct physicochemical compositions. The membranes were first discriminating by their ability to reject uranium in the presence of the main cations found in mineral waters, using a 2 mg L(-1) (2000 ppb) concentration of uranium. The rejection of U(VI) was dependent on the uranyl speciation and the ionic strength. Second, removal of uranium traces (0.02 mg L(-1), 20 ppb) was performed using the nanofiltration membrane showing the highest selectivity for uranium toward alkaline and alkaline-earth ions. The results showed a high performance of the nanofiltration membrane, Osmonics DL, for selective uranium rejection at low pressure (1 bar), illustrating the advantage of nanofiltration for the selective removal of uranium from drinking water.

A new method for the benzoin condensation is proposed in imidazolium-based ionic liquids as solvents/catalysts. The use of a 30 kHz ultrasonic irradiation as activation method provides a quantitative yield of benzoin in 1-octyl-3-methyl-imidazolium bromide without degrading the ionic medium which can be-reused at least three times with no loss of activity.

A new mild and environmental friendly benzylic oxidation with good to excellent yields is presented.

A new and efficient methodology was developed for the selective benzylic C–H oxidation using tert- butyl hydroperoxide as the oxidant and Fe(TAML)Li as the catalyst. The oxidation of various simple benzylic compounds was carried out with good to excellent yields and/or selectivity. A plausible mechanism for the reaction is proposed.

A solventless benzoin condensation was performed with several imidazolium-based ionic liquids as catalysts under microwave irradiation. The process enables the formation of α-hydroxy-α-phenylacetophenone with good yield (up to 97%) and purity in a very short time. Moreover, the work-up only requires the use of water, giving a green touch to the overall process.

Cloud-point extraction (CPE) was used with lipophilic chelating agent to extract uranium(VI) from aqueous solutions. The methodology used is based on the formation of metal complexes soluble in a micellar phase of a non-ionic surfactant, Triton X-114. The metal ions complexes are then extracted into the surfactant-rich phase at a temperature above the cloud-point temperature. The influence of surfactant concentration on extraction efficiency was studied and the advantage of adding 8-hydroxyquinoline (8HQ) as lipophilic chelating agent was evidenced. High extraction efficiency was observed, indicating the feasibility of extracting U(VI) using CPE. This study describes a four-step process—(1) extraction, (2) thermo-induced phase splitting, (3) back-extraction and (4) second phase splitting—for the recovery of uranium from water. In our conditions, the extraction yield is quantitative and the concentration factor obtained is superior to 100. After stripping with a diluted nitric acid solution (pH < 1), the system can be recycled through a new four-step cycle. Copyright © 2006 Society of Chemical Industry

Cross‐flow membrane filtration equipment was operated to evaluate the selective uranium carbonate rejection from seawater of different flat sheet membranes. The membranes were discriminating by the rejection of uranium, calcium, and sodium under geochemical conditions that mimic uranium in seawater. Then, operating parameters were optimized, and the selective rejection of dissolved uranium was checked on prefiltrated seawater. Concentration factors of 1.1 and 8.5 for sodium and uranium(VI), respectively, were obtained for a nanofiltration volume ratio of 0.96.

A less‐common extraction procedure, cloud‐point extraction, is used with a lipophilic chelating agent (8‐hydroxyquinoline) to extract and separate lanthanum(III) and gadolinium(III) ions from an aqueous solution. Surfactant solutions are used in conjunction with 8‐hydroxyquinoline to form a lanthanide complex that is extracted into the micellar phase at a temperature above the cloud‐point temperature. The structure of the lipophilic part of the nonionic surfactant, the chelating agent–metal molar ratio, and the cloud‐point temperature are identified as factors determining the extraction efficiency and selectivity. With Triton X‐114, a selectivity higher than 30 and a decontamination factor of 50 for Gd(III) indicate that micelle‐mediated cloud‐point extraction is promising for the specific separation of actinide ions from nuclear waste. Finally, a microwave procedure is proposed to decrease the duration of the experiment to less than 6 min. The authors are grateful to Seppic S.A., Paris, France, ...

A new procedure for the concentration of uranium, dissolved in seawater with extremely low concentration, was studied. Plate module membrane filtration equipment was operated to evaluate the performance and selectivity of four different nanofiltration flat sheet membranes. Experiments were first carried out using different model waters. The membranes were discriminating by the rejection of uranium, calcium, and sodium. Then, a uranium concentration test using a nanofiltration membrane showing the highest selectivity for uranium toward alkaline and alkaline-earth ions has been performed on natural seawater. A nanofiltration membrane shows a high selectivity for U(VI), illustrating the advantageous use of nanofiltration for the concentration of uranium from seawater.

We obtained novel hybrid materials on the basis of covalently bounded to amino-grafted tin dioxide lipase from Rhizopus delemar (NH 2 -nano-SnO 2 -RhD). Under the optimal condition, the protein loading yielded of 14.7 mg/g NH 2 -nano-SnO 2 , while the adsorption capacity of the unmodified nano-SnO 2 for the same enzyme was 38.5 mg/g. At the same time, NH 2 -nano-SnO 2 -RhD exhibited specific hydrolytic activity of 77.6 U/mg prot. which is 2.5-fold higher in comparison to that of the physically adsorbed on nano-SnO 2 lipase (nano-SnO 2 -RhD). In ten reaction cycles of tributyrin hydrolysis, up to 70% of the activity of NH 2 -nano-SnO 2 -RhD was preserved. Upon immobilization the enantioselectivity of the lipase for the reaction of acylation of (±)-menthol was improved. For the two biocatalysts, the highest yield of (−)-menthyl acetate (more than 35%) was obtained when glyceryl triacetate was used as acylating reagent, however, the enantiomeric excess was only 89.5% for the covalently bonded lipase and 85.0% for the physically adsorbed one. Higher enantiomeric excess was obtained when vinyl acetate was used as an acylating reagent; however, the conversion in that case did not exceed 20%. The addition of small amounts of pyrrolidinium-based ionic liquids, 1-methyl-1-octyl-pyrrolidinium bis(trifluoromethyl)sulfonyl imide [MOPyrro][NTf 2 ], 1-methyl-1-octyl-pyrrolidinium hexafluorophosphate [MOPyrro][PF 6 ], and 1-methyl-1-octyl-pyrrolidinium tetrafluoroborate [MOPyrro][BF 4 ], to the reaction mixture resulted in decrease of (±) menthol conversion rate. All tested ionic liquids enhanced the enantioselectivity of nano-SnO2-RhD, and the best result was obtained in presence of [MOPyrro][PF6] (enantiomeric ratio >140).

Long-term radiotoxicity of nuclear waste produced during spent nuclear fuel reprocessing could be reduced if the minor actinides (neptunium, americium and curium) contained within the waste are separated into short-lived radionuclides for their subsequent transmutation or for separate storage. Cross-linked phenolic resins based on different substituted phenol were shown to be very efficient for selective uptake of Eu3+ from aqueous solutions containing equal amounts of La3+. In this work, we have prepared and characterized cross-linked phenol based resins to investigate the uptake of 243Am. According to the results obtained for Eu selective extraction and to enhance 243Am sorption, the resins are transformed into their Na+–forms before extraction. The ion selectivities of the cross-linked phenol based resins are then compared as a function of the identity of the ion-exchange phenolic matrix. Radiation stability of the resins was studied and each resin was measured for the effect of ionizing radiations wit...

Micellar enhanced ultrafiltration (MEUF) represents a potentially attractive tool for the removal of different contaminants from waste waters. The work presented in this paper was aimed at investigating the use of MEUF to remove 4,4'-isopropylidenediphenol [also known as 2,2-bis(4-hydroxyphenyl) propane and commercially available as bisphenol A or DIANE] from aqueous streams. Three surfactants, sodium dodecylsulphate (SDS), hexadecyltrimethyl ammonium bromide (CTAB) and alkylpolyglucoside Glucopon 215 SCUP (APG) were used to form the micellar structure both in the absence and in the presence of NaHCO3 as an electrolyte. CTAB which form cationic micelles gave the best performances in terms of bisphenol A rejection and micelle loading capacity. This may be as a result of the influence of various factors including the existence of a preferential interaction between the positive charge of the ammonium site of CTAB and the n -electron cloud of the aromatic rings of bisphenol A, as well as differences ...

Catechol, resorcinol, and their admixtures with 8-hydroxyquinoline were converted into polymeric resins by alkaline polycondensation with formaldehyde. The resins were characterized by FTIR spectroscopy, moisture regain, ion-exchange capacity, and distribution coefficient (D) for Eu3+. Thermogravimetric analysis of the polymer samples was studied, and the effect of the sorption of metal ions on their thermal stability was evaluated. Complexation of Eu3+ to the resins was modeled based on metal ion charge neutralization. The selective uptake of Eu3+ from aqueous solutions containing La3+ was investigated, and the ionoselectivities of the resins were compared. The incorporation of 8-hydroxyquinoline in the molecular matrix of the phenolic resins is shown to exert a significant influence upon the competitive sorption of La3+ and Eu3+, leading to their intragroup separation. The separation factors obtained by phenolic ion-exchange resins from aqueous solutions indicate ion-specific resins can be developed for...