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International audience; Three new organic compounds primarily based on 8-hydroxyquinoline have been successfully synthesized and characterized via different spectroscopic methods (FTIR, H-1, and C-13 NMR). The synthesized compounds, namely 5-propoxymethyl-8-hydroxyquinoline (PMHQ), 5-methoxymethyl-8-hydroxyquinoline (MMHQ) and 5-hydroxymethyl-8-hydroxyquinoline (HMHQ), were evaluated as corrosion inhibitors for carbon steel in 1 M HCl solution using electrochemical impedance spectroscopy, potentiodynamic polarization and weight loss measurements at 298 K. Electrochemical measurements confirmed that the newly synthesized 5-alkoxymethyl-8-hydroxyquinoline derivatives are mixed type corrosion inhibitors and confirmed maximum protection efficiencies of 94, 89 and 81% for PMHQ, MMHQ, and HMHQ, respectively, at the optimum concentration of 10(-3) M. The EIS spectra confirmed a slightly depressed semi-circle profile with a single time constant in Bode diagrams for the three organic compounds over the whole concentration and temperature ranges studied. The adsorption of PMHQ, MMHQ, and HMHQ on the carbon steel surface followed the Langmuir adsorption isotherm. In addition, the kinetic and thermodynamic parameters for carbon steel corrosion and inhibitor adsorption, respectively, were determined and discussed. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) analyses supported the formation of a protective film on carbon steel in the presence of PMHQ, MMHQ, and HMHQ. Density functional theory calculations (DFT) showed that the effectiveness of the inhibitive actions of the studied compounds correlates well with their electron donating ability, whilst Monte Carlo simulations revealed that the extent and favourability of adsorption of inhibitor molecules on the carbon steel surface establish their corrosion inhibition performances.

Deep-sea corals are a potentially valuable archive of the temperature and ocean chemistry of intermediate and deep waters. Living in near-constant temperature, salinity, and pH and having amongst the slowest calcification rates observed in carbonate-precipitating biological organisms, deep-sea corals can provide valuable constraints on processes driving mineral equilibrium and disequilibrium isotope signatures. Here we report new data to further develop “clumped” isotopes as a paleothermometer in deep-sea corals as well as to investigate mineral-specific, taxon-specific, and growth-rate-related effects. Carbonate clumped isotope thermometry is based on measurements of the abundance of the doubly substituted isotopologue 13C18O16O2 in carbonate minerals, analyzed in CO2 gas liberated on phosphoric acid digestion of carbonates and reported as Δ47 values. We analyzed Δ47 in live-collected aragonitic scleractinian (Enallopsammia sp.) and high-Mg calcitic gorgonian (Isididae and Coralliidae) deep-sea corals and compared results to published data for other aragonitic scleractinian taxa. Measured Δ47 values were compared to in situ temperatures, and the relationship between Δ47 and temperature was determined for each group to investigate taxon-specific effects. We find that aragonitic scleractinian deep-sea corals exhibit higher values than high-Mg calcitic gorgonian corals and the two groups of coral produce statistically different relationships between Δ47–temperature calibrations. These data are significant in the interpretation of all carbonate clumped isotope calibration data as they show that distinct Δ47–temperature calibrations can be observed in different materials recovered from the same environment and analyzed using the same instrumentation, phosphoric acid composition, digestion temperature and technique, CO2 gas purification apparatus, and data handling. There are three possible explanations for the origin of these different calibrations. The offset between the corals of different mineralogy is in the same direction as published theoretical predictions for the offset between calcite and aragonite although the magnitude of the offset is different. One possibility is that the deep-sea coral results reflect high-Mg and aragonite crystals attaining nominal mineral equilibrium clumped isotope signatures due to conditions of extremely slow growth. In that case, a possible explanation for the attainment of disequilibrium bulk isotope signatures and equilibrium clumped isotope signatures by deep-sea corals is that extraordinarily slow growth rates can promote the occurrence of isotopic reordering in the interfacial region of growing crystals. We also cannot rule out a component of a biological “vital effect” influencing clumped isotope signatures in one or both orders of coral. Based on published experimental data and theoretical calculations, these biological vital effects could arise from kinetic isotope effects due to the source of carbon used for calcification, temperature- and pH-dependent rates of CO2 hydration and/or hydroxylation, calcifying fluid pH, the activity of carbonic anhydrase, the residence time of dissolved inorganic carbon in the calcifying fluid, and calcification rate. A third possible explanation is the occurrence of variable acid digestion fractionation factors. Although a recent study has suggested that dolomite, calcite, and aragonite may have similar clumped isotope acid digestion fractionation factors, the influence of acid digestion kinetics on Δ47 is a subject that warrants further investigation.

International audience; Activated carbons are widely used as supports for industrial catalysts based on metal nanoparticles. The catalytic performance of carbon-supported catalysts is strongly influenced by the carbon activation method. Notwithstanding this important role, the effect induced by different activation methods has been rarely investigated in detail. This work deals with two carbons of wood origin, activated either by steam or by phosphoric acid, and the corresponding catalysts based on supported Pd nanoparticles. We demonstrate that the catalysts perform in a different way in hydrogenation reactions depending on the nature of the carbon used as a support, being the palladium dispersion the same. We propose a multi-technique approach to fully characterize both carbons and catalysts at the micro-and nanoscale. In particular, we investigate how the activation procedure influences the texture (by N-2 physisorption), the morphology (by Scanning Electron Microscopy), the structure (by Solid State Nuclear Magnetic Resonance, Raman spectroscopy and X-ray Diffraction) and the surface properties (by X-ray Photoelectron Spectroscopy, Diffuse Reflectance Infrared Spectroscopy and Inelastic Neutron Scattering) of carbons and of the related catalysts. The comprehensive characterization approach proposed in this work allows the rationalization, at least in part, of the role of activated carbons in enhancing the performance of a hydrogenation catalyst

International audience; Our understanding of the evolutionary transitions leading to the modern endothermic state of birds and mammals is incomplete, partly because tools available to study the thermo-physiology of extinct vertebrates are limited. Here we show that clumped isotope analysis of eggshells can be used to determine body temperatures of females during periods of ovulation. Late Cretaceous titanosaurid eggshells yield temperatures similar to large modern endo-therms. In contrast, oviraptorid eggshells yield temperatures lower than most modern endotherms but B6 °C higher than co-occurring abiogenic carbonates, implying that this taxon did not have thermoregulation comparable to modern birds, but was able to elevate its body temperature above environmental temperatures. Therefore, we observe no strong evidence for end-member ectothermy or endothermy in the species examined. Body temperatures for these two species indicate that variable thermoregulation likely existed among the non-avian dinosaurs and that not all dinosaurs had body temperatures in the range of that seen in modern birds.

International audience; Activated carbons were prepared from biomass of Algerian date pits for developing efficient and cheap adsorbents in the aim to remove heavy metals from waste water. Carbon adsorbents were obtained following two successive treatments: pyrolysis under dry nitrogen flow and physical activation under wet nitrogen flow. Pyrolysis process was optimized by varying some operating parameters such as temperature, nitrogen flow, heating rate and pyrolysis hold time in order to determine their effects on the porous structure development of date pits activated carbon. Chars obtained from pyrolysis process were activated with the same operating conditions (activation temperature of 700 degrees C, 50% nitrogen + 50% water flow rate of 150 cm(3)/min and heating rate of 10 degrees C/min) except for the activation hold time which varied from 0.5 to 4h. Experimental results showed that pyrolysis conditions have significant effects on the chars and activated carbons properties prepared from date pits. The best rnicroporous activated carbon (surface area of 464 m(2)/g, microporous volume of 0.203 cm(3)/g and total pore volume of 0.220 cm(3)/g) was obtained by pyrolysis at 10 degrees C/min up to 700 degrees C for 1 h under 150 cm(3)/min of nitrogen. Activation hold time has also an impact on activated carbons porosity. The best surface area. microporous volume and total pore volume were obtained after activation for 4 h: 1467 m(2)/g. 0.711 cm(3)/g and 0.725 cm(3)/g respectively. The best adsorbents prepared from date pits were then tested for the removal of Fe3+ and Cu2+ from aqueous solutions. Results show that these adsorbents have higher metallic cation adsorption capacities than usual commercial activated carbons because of the presence of both carboxylic and phenolic groups at the surface witch improves the cation-exchange and complexation properties of these adsorbents in addition of the greater specific surface area. Adsorption data were analyzed with Langmuir and Freundlich isotherms. The better fit is obtained with the Langmuir model.

A novel one-pot, three-component synthesis of N-acyl or N-carbamoyl-alpha-amidosulfides 4 is described. The three-component reaction of aldehydes 1, primary carbamates (or amides) 2 and phenylsulfinic acid (6a) afforded alpha-amidosulfones 7, which after addition of sodium thiolate were in situ transformed into stable alpha-amidosulfides 4 in good to excellent yields. We demonstrated that silver salts or Bronsted acids were able to promote the formation of aliphatic and aromatic N-acylimines from 4 in quantitative yield under mild conditions. The phosphoric acid catalyzed Friedel-Crafts alkylation of 3-substituted indoles with alpha-amidosulfides 4 leading to 2,3-disubstitued indoles was also documented.