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11.
Benoit Rigo Philippe Gautret Anne Legrand Samira El Ghammarti Daniel Couturier 《合成通讯》2013,43(18):2609-2615
Starting from the readily available N,O-bis trimethylsilyl pyroglutamate, an easy high yield one pot synthesis of ketone 1 was described. 相似文献
12.
Sharifkhani Samira M. Yaftian Mohammad Reza Hosseini Majid Haji Zolfonoun Ehsan 《Journal of Analytical Chemistry》2022,77(4):505-512
Journal of Analytical Chemistry - In this study, for the first time, the organic gas steam-liquid extraction by a special hand-made cell was used as a simple and inexpensive preconcentration... 相似文献
13.
Olga Koba-Ucun Tuba
lmez Hanci Idil Arslan-Alaton Samira Arefi-Oskoui Alireza Khataee Mehmet Kobya Yasin Orooji 《Molecules (Basel, Switzerland)》2021,26(2)
The application of layered double hydroxide (LDH) nanomaterials as catalysts has attracted great interest due to their unique structural features. It also triggered the need to study their fate and behavior in the aquatic environment. In the present study, Zn-Fe nanolayered double hydroxides (Zn-Fe LDHs) were synthesized using a co-precipitation method and characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and nitrogen adsorption-desorption analyses. The toxicity of the home-made Zn-Fe LDHs catalyst was examined by employing a variety of aquatic organisms from different trophic levels, namely the marine photobacterium Vibrio fischeri, the freshwater microalga Pseudokirchneriella subcapitata, the freshwater crustacean Daphnia magna, and the duckweed Spirodela polyrhiza. From the experimental results, it was evident that the acute toxicity of the catalyst depended on the exposure time and type of selected test organism. Zn-Fe LDHs toxicity was also affected by its physical state in suspension, chemical composition, as well as interaction with the bioassay test medium. 相似文献
14.
Samira Ouardad Sergei V. Kostjuk François Ganachaud Judit E. Puskas Alain Deffieux Frederic Peruch 《Journal of polymer science. Part A, Polymer chemistry》2011,49(23):4948-4954
The polymerization of isoprene initiated by dimethylallyl alcohols (DMAOH) in the presence of Lewis acids (LAs) as coinitiators has been selected as a potential model of the proposed cationic mechanisms involved in natural rubber (NR) biosynthesis. In view to investigate the activation/ionization mechanism of the allyl alcohol chain terminus (PIAllOH), which was shown to exist in NR, different isomers of DMAOH were used as simple models of polyisoprene chain‐end structures in the presence of tris(pentafluorophenyl)borane (BLA) as a LA. It is shown that cationation of 3,3‐DMAOH by BLA proceeds by direct OH abstraction. However, this process is strongly retarded in the presence of 2,6‐di‐tert‐butylpyridine (dtBP), due to the formation of different BLA complexes, one with 3,3‐DMAOH, active for cationation, and a dormant one involving its ionized form 3,3‐DMAO?. The monomer generated in situ by ionization/proton elimination steps subsequently adds on the primary allylic carbocation form, then resulting in the formation of oligoisoprenes, whereas the tertiary carbocation form of the allylic carbocation yields exclusively to proton elimination and isoprene formation, a possible mechanism of chain‐end termination. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011. 相似文献
15.
Abedinifar Fahimeh Babazadeh Rezaei Elham Biglar Mahmood Larijani Bagher Hamedifar Halleh Ansari Samira Mahdavi Mohammad 《Molecular diversity》2021,25(4):2571-2604
Molecular Diversity - Thiophene-based analogs have been fascinated by a growing number of scientists as a potential class of biologically active compounds. Furthermore, they play a vital role for... 相似文献
16.
A very efficient and mild procedure for preparation of silyl ethers from benzylic, allylic, propargilic alcohols, phenols, naphtoles and some of phenolic drugs with trimethylsilylchloride (TMSCl), triethylsilylchloride (TESCl) and t‐buthyldimethylsilyl chloride (TDSCl) ethers in the presence of Fe(HSO4)3/Et3N in room temperature in excellent yields is reported. This procedure also allows the excellent selectivity for silylation of alcohols and phenols. 相似文献
17.
Marius Murariu Samira Benali Yoann Paint Anne-Laure Dechief Oltea Murariu Jean-Marie Raquez Philippe Dubois 《Molecules (Basel, Switzerland)》2021,26(7)
Due to the added value conferred by zinc oxide (ZnO) nanofiller, e.g., UV protection, antibacterial action, gas-barrier properties, poly(lactic acid) (PLA)–ZnO nanocomposites show increased interest for utilization as films, textile fibers, and injection molding items. The study highlights the beneficial effects of premixing ZnO in PLA under given conditions and its use as masterbatch (MB), a very promising alternative manufacturing technique. This approach allows reducing the residence time at high processing temperature of the thermo-sensitive PLA matrix in contact of ZnO nanoparticles known for their aptitude to promote degradation effects onto the polyester chains. Various PLA–ZnO MBs containing high contents of silane-treated ZnO nanoparticles (up to 40 wt.% nanofiller specifically treated with triethoxycaprylylsilane) were produced by melt-compounding using twin-screw extruders. Subsequently, the selected MBs were melt blended with pristine PLA to produce nanocomposite films containing 1–3 wt.% ZnO. By comparison to the more traditional multi-step process, the MB approach allowed the production of nanocomposites (films) having improved processing and enhanced properties: PLA chains displaying higher molecular weights, improved thermal stability, fine nanofiller distribution, and thermo-mechanical characteristic features, while the UV protection was confirmed by UV-vis spectroscopy measurements. The MB alternative is viewed as a promising flexible technique able to open new perspectives to produce more competitive multifunctional PLA–ZnO nanocomposites. 相似文献
18.
Samira Bagheri Fereshteh Chekin Sharifah Bee Abd Hamid 《Russian Journal of Electrochemistry》2014,50(10):947-952
Anatase titanium dioxide nanoparticles (TiO2-NPs) were synthesized with and without gelatin via the sol-gel method. The TiO2-NPs were characterized by a number of techniques, such as thermogravimetric analysis (TGA), X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FT-IR) and ultraviolet visible spectroscopy (UV-Vis). The particle sizes of the TiO2-NPs prepared with and without gelatin were ~13 and ~17 nm, respectively. The main advantage of using gelatin as a stabilizing agent is that it provides long-term stability for nanoparticles by preventing particles agglomeration. The results indicated that gelatin was a reliable green stabilizer, which can be used as a polymerization agent in the sol-gel method for synthesis of tiny size TiO2-NPs. Moreover, the composite film was prepared by synthesized TiO2-NPs nanoparticles and multi wall carbon nanotube (MWNT) on glassy carbon electrode (TiO2-MWNT/GCE). The TiO2-MWNT/GCE responded linearly to L-tryptophan (L-Trp) in the concentration of 1.0 × 10?6 to 1.5 × 10?4 M with detection limit of 5.2 × 10?7 M at 3 using amperometry. The studied sensor exhibited good reproducibility and long-term stability. 相似文献
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