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241.
242.
Issa Yavari Nargess Hosseini Loghman Moradi Anvar Mirzaei 《Tetrahedron letters》2008,49(27):4239-4241
A mild, convenient, and practical one-pot procedure for direct synthesis of N,N′-dialkyl-N″-dialkylaminocarbothioyl thioureas is described via three-component reaction of cyclic secondary amines, CS2, and N,N′-dialkyl carbodiimides in water at room temperature. 相似文献
243.
Applications of functionalized ionic liquids 总被引:2,自引:0,他引:2
LI Xuehui ZHAO Dongbin FEI Zhaofu & WANG Lefu . Department of Chemical Engineering Guangdong Provincial Laboratory of Green Chemical Technology South China Uni-versity of Technology Guangzhou China . Swiss Federal Institute of Technology Lausanne EPFL CH- Lausanne Switzerland . PKU Green Chemistry Center Beijing National Laboratory for Molecular Sciences College of Chemistry Molecular Engineering Peking University Beijing China 《中国科学B辑(英文版)》2006,49(5):385-401
Recent developments of the synthesis and applications of functionalized ionic liquids (including dual-functionalized ionic liquids) have been highlighted in this review. Ionic liquids are at-tracting attention as alternative solvents in green chemistry, but as more functionalized ILs are pre-pared, a greater number of applications in increasingly diverse fields are found. 相似文献
244.
Sidra Amin Aneela Tahira Amber R. Solangi Raffaello Mazzaro Zafar Hussain Ibupoto Almas Fatima Alberto Vomiero 《Electroanalysis》2020,32(5):1052-1059
Nickel oxide (NiO) nanostructures are employed in the basic medium for the oxidation of ethanol. A variety of NiO nanostructures are synthesized by wet chemical growth method, using different hydroxide (OH?) ion sources, particularly from ammonia, hexamethylenetetramine, urea and sodium hydroxide. The use of urea as (OH?) ion source results in flower‐like NiO structures composed by extremely thin nanowalls (thickness lower than 10 nm,), which demonstrated to be the most active for ethanol oxidation. All the samples exhibit NiO cubic phase, and no other impurity was detected. The cyclic voltammetry (CV) curves of NiO nanostructures were found linear over the concentration range 0.1–3.5 mM (R2=0.99) of ethanol, with the limit of detection estimated to be 0.013 mM for ethanol. The NiO nanostructures exhibit a selective signal towards ethanol oxidation in the presence of different members of alcohol family. The proposed NiO nanostructures showed a significant practicality for the reproducible and sensitive determination of ethanol from brandy, whisky, mixture of brandy and rum, and vodka samples. The nanomaterial was used as a surface modifying agent for the glassy carbon electrode and it showed a stable electro‐oxidation activity for the ethanol for 16 days. These findings indicate that the presented NiO nanomaterial can be applied in place of noble metals for ethanol sensing and other environmental applications (like fuel cells). 相似文献
245.
Dr. Si-Yong Qin Yan Jiang Dr. Han Sun Han Liu Prof. Ai-Qing Zhang Prof. Xinxiang Lei 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(39):17245-17251
Residual dipolar coupling (RDC), a robust anisotropic NMR parameter for structural elucidation of organic molecules, is only accessible in an anisotropic environment. Herein, we introduce a novel alignment medium based on the molecular self-assembly of oligopeptide amphiphile (OPA). This medium is compatible with different intermediate and polar solvent systems, such as CD3OD, [D6]DMSO, and D2O. The preparation of the OPA-based medium is simple and rapid, while only very weak background signals were observed from OPAs. Furthermore, we show that the purity of OPA has only a minor influence on the quality of the RDC data. These advantages allow RDC measurements of organic molecules with different polarities and solubilities with high efficiency and accuracy. 相似文献
246.
Diandian Shi Dr. Kok-Giap Haw Dr. Cassandre Kouvatas Lingxue Tang Yiying Zhang Prof. Dr. Qianrong Fang Prof. Dr. Shilun Qiu Prof. Dr. Valentin Valtchev 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(44):19744-19749
Aluminosilicate zeolites are synthesized under hydrothermal conditions in a basic/alkaline medium in the pH range between 9 and 14. The synthesis of MFI-type zeolite in an acidic medium is presented. The critical parameter determining the zeolite formation in an acidic medium was found to be the isoelectric point (IEP) of gel particles. MFI-type zeolite was synthesized above the isoelectric point of the employed silica source, where the silica species exhibit a negative charge and the paradigm of zeolite formation based on the electrostatic interaction with the positively charged template is retained. No zeolite formation is observed below the isoelectric point of silica. The impact of aluminum on the zeolite formation is also studied. The results of this study will serve to extend the synthesis field of high silica zeolites to the acidic medium and thus open new opportunities to control the zeolite properties. 相似文献
247.
Ken Hosoya Jean M. J. Frchet 《Journal of polymer science. Part A, Polymer chemistry》1993,31(8):2129-2141
Monodisperse polymer particle-based separation media were prepared by a multi-step swelling and polymerization method with two pairs of monomers and two porogenic solvents. Their chromatographic properties were compared to those of beads prepared by a corresponding suspension polymerization method without the use of seed polymer to ascertain the influence of the seed polymer on their porous structures. A large change in porous structure was observed when the swollen particle consisting of monomers and porogenic solvents contained at least one good solvent for the polystyrene seed polymer, allowing it to remain in the polymerizing medium. In contrast, when the polystyrene seed particle was excluded from the swollen oil droplets, due to its poor solubility in the monomers and the porogenic solvents, there was no difference in the chromatographic properties such as pore volume, pore size, pore size distribution, or retention selectivity between the multi-step swelling and polymerization method and the suspension polymerization method. Since the only difference between the multi-step swelling and polymerization method and the suspension method is the use of the seed polymer, it appears that a very small amount (< 1% v/v) of seed polymers in the enlarged swollen droplets plays an important role as a porogen and affects the porous structure as well as the chromatographic properties of the monodisperse polymer particle-based separation media. © 1993 John Wiley & Sons, Inc. 相似文献
248.
丙烯酸聚合物及其与其它水性单体的共聚物是一类非常重要的水溶性高分子化合物, 具有许多优异的性能, 广泛应用于环保、 石油化工、 造纸和食品卫生等行业[1]. 丙烯酸聚合物一般采用水溶液、 反相悬浮及反相乳液法制备, 但这些方法存在诸如反应体系粘度高, 不易散热、 使用不方便, 由于使用有机溶剂和表面活性剂易对环境造成二次污染等问题[2].近些年, 由日本率先研制开发的以水为溶剂分散型高浓度﹑高分子量的新型水溶性高分子产品, 克服了传统合成方式和产品剂型等诸多问题, 极大地拓宽了其使用领域[3~5]. 有关水介质中水溶性单体分散聚合的研究报道很少[6~8].而针对于丙烯酸在水介质中的研究报道则更少[9] , 大部分工作为专利文献. 相似文献
249.
Miwa Kubo 《Tetrahedron letters》2006,47(12):1927-1931
We synthesized a peptidocalix[4]arene library consisting of 1000 members that was suitable for peptide recognition in aqueous media. Some peptidocalix[4]arenes in the library were host molecules for guest peptides. Electrostatic interaction between the host and guest molecules was the most important factor for binding in aqueous media. 相似文献
250.
A mild and efficient protocol for the coupling of indoles and pyrroles with allyl halides such as allyl bromide, crotyl bromide and propargyl bromide in the presence of gallium metal in a Bu4NBr-DMF-H2O system has been developed. The reaction is equally effective when cadmium is used in lieu of gallium and the corresponding 3-allyl indoles and 3-allyl pyrroles were obtained in almost comparable yields. 相似文献