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Chahinez Benbayer Salima Saidi-Besbes Elisabeth Taffin de Givenchy Sonia Amigoni Frédéric Guittard Aicha Derdour 《Colloid and polymer science》2014,292(7):1711-1717
The radical copolymerization of three polymerizable surfactants with styrene was investigated by NMR spectroscopy to assess their compositions. The reactivity ratios of these monomers were calculated according to the methods of Fineman–Ross and Kelen–Tüdos. Consequently, Q and e values were deduced by the Alfrey and Price method. The results indicated the positive effect of the fluorine chain on the reactivity of monomers bearing a long spacer between the ammonium head and the acrylic function. These monomers exhibit high e values which are in favor of an intramolecular conformation of the surfactant where the ester carbonyl function of the polymerizable group interacts with the onium nitrogen atom via a compact six-sided structure. 相似文献
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Mengwei Yuan Sofiene Abdellaoui Hui Chen Matthew J. Kummer Christian A. Malapit Chun You Shelley D. Minteer 《Angewandte Chemie (International ed. in English)》2020,59(23):8969-8973
Aliphatic synthetic intermediates with high added value are generally produced from alkane sources (e.g., petroleum) by inert carbon–hydrogen (C?H) bond activation using classical chemical methods (i.e. high temperature, rare metals). As an alternative approach for these reactions, alkane monooxygenase from Pseudomonas putida (alkB) is able to catalyze the difficult terminal oxyfunctionalization of alkanes selectively and under mild conditions. Herein, we report an electrosynthetic system using an alkB biocathode which produces alcohols, epoxides, and sulfoxides through bioelectrochemical hydroxylation, epoxidation, sulfoxidation, and demethylation. The capacity of the alkB binding pocket to protect internal functional groups is also demonstrated. By coupling our alkB biocathode with a hydrogenase bioanode and using H2 as a clean fuel source, we have developed and characterized a series of enzymatic fuel cells capable of oxyfunctionalization while simultaneously producing electricity. 相似文献
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Nadia Gmati Khaled Boughzala Mohieddine Abdellaoui Khaled Bouzouita 《Comptes Rendus Chimie》2011,14(10):896-903
The britholites have gained a great interest thanks to their potential applications as matrices for the confinement of the byproducts in the nuclear industry such as minor actinides and long-lived fission products. However, the preparation of britholites requires high temperatures, above 1200 °C. In this work, we strive to prepare these kinds of compounds by a mechanochemical synthesis at room temperature from the starting materials SrF2, SrCO3, Sr2P2O7, La2O3 and SiO2 using a planetary ball mill. The obtained results showed that the prepared products were carbonated apatites and the corresponding powders contained some unreacted silica and lanthana. To obtain pure britholites, a heat-treatment at 1100 °C was required. The mechanism involved in the different steps of the reaction is discussed in this paper. The obtained results suggest that the use of raw materials containing no carbonate is expected to directly lead to pure britholites by appropriate milling at room temperature. 相似文献
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In this article we analyze existence and nonexistence of positive solutions to problem
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Hélène Nouailhas Chahinez Aouf Christine Le Guerneve Sylvain Caillol Bernard Boutevin Hélène Fulcrand 《Journal of polymer science. Part A, Polymer chemistry》2011,49(10):2261-2270
Biobased epoxy resins were synthesized from a catechin molecule, one of the repetitive units in natural flavonoid biopolymers also named condensed tannins. The reactivity of catechin toward epichlorohydrin to form glycidyl ether derivatives was studied using two model compounds, resorcinol and 4‐methylcatechol, which represent the A and B rings of catechin, respectively. These model molecules clearly showed differences in reactivity upon glycidylation, explaining the results found with catechin monomer. The reaction products were characterized by both FTIR and NMR spectroscopy and chemical assay. The glycidyl ether of catechin (GEC) was successfully cured in various epoxy resin formulations. The GECs thermal properties showed that these new synthesized epoxy resins displayed interesting properties compared to the commercial diglycidyl ether of bisphenol A (DGEBA). For instance, when incorporated up to 50% into the DGEBA resin, GEC did not modify the glass‐transition temperature. Epoxy resins formulated with GEC had slightly lower storage moduli but induced a decrease of the swelling percentage, suggesting that GEC‐enhanced crosslinking in the epoxy resin networks. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
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The essential oil of the leaves of Pistacia lentiscus, collected from the middle Atlas in Morocco, was analyzed by GC and GC-MS. Altogether 43 components in concentrations of more than 0.2% were identified representing 97.4% of the oil composition. The main constituents were germanicol (12.8%), thunbergol (8.8%), himachalene (7.4%), trans-squalene (6.7%), terpinyl propionate (6.7%), 3,3-dimenthol (6.2%) and cadina-1.4-diene (5.1%). The oils showed strong activity against Klebsiella pneumonia, but no activity against Pseudomonas aeruginosa. 相似文献
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Audrey Combes Saïda El Abdellaoui Jérome Vial Emmeline Lagrange Valérie Pichon 《Analytical and bioanalytical chemistry》2014,406(19):4627-4636
The cyanotoxin β-methylamino-l-alanine (BMAA) has received renewed attention as an environmental risk factor for sporadic cases of amyotrophic lateral sclerosis (ALS) (Nunn et al., Brain Res 410:375–379, 1987). The aim of the present study was to develop and to validate an analytical procedure that allows the quantification of native BMAA and of its natural isomer, 2,4 diaminobutyric acid (DAB), in brain tissues. An analytical procedure was previously reported by our group for the determination of underivatized BMAA in environmental samples. It included a step of sample clean-up by solid phase extraction (SPE) with a mixed-mode sorbent and the analyses were performed by LC/MS-MS using hydrophilic interaction chromatography and multiple reactions monitoring scan mode. As brain tissues have a higher lipid content, the crucial step of sample clean-up had been optimized by evaluating the efficiency of the addition of a liquid/liquid extraction step prior to the SPE procedure or alternatively, of washing steps to the SPE extraction procedure. The efficiency was checked by visualizing the complexity of the resulting chromatograms in LC/MS and their performance by using spiked brain samples. The optimized analytical procedure, including a washing step with cyclohexane to the SPE with a recovery yield close to 100 %, was validated using the total error approach and allowed the quantification of BMAA in a concentration level ranging from 20 to 1,500 ng/g in brain samples. Finally, the feasibility of implementation of this procedure was verified in human brain samples from two patients who died of ALS. 相似文献