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81.
82.
Aminolysis of a variety of epoxides by aliphatic and aromatic amines in water, in the absence of any catalyst with high yields, is reported. Beta-amino alcohols were formed under mild conditions with high selectivity and in excellent yields. [reaction: see text] 相似文献
83.
A practical and straightforward protocol has been developed for the preparation of 2-thioxo-2,3-dihydroquinazolin-4(1H)-one derivatives from dithiocarbamate chemistry. The method involves the reaction of anthranilic acid derivatives (2-aminobenzoic acid, 2-aminobenzamide and isatoic anhydride) with various dithiocarbamate derivatives using ethanol as solvent. The main advantages of this protocol include practical simplicity, good to high yields, and ease of product isolation, purification and cheapness of the solvent. 相似文献
84.
Catalin Florin Petre Abdelaaziz Azizi Caroline Olsen Abdelaziz Baçaoui Faïçal Larachi 《Journal of separation science》2008,31(22):3902-3910
A capillary electrophoretic protocol for the separation and quantification of the most important species potentially liberated during the cyanidation of gold sulfide‐rich ores was accomplished in this study. The separation of 11 ions: S2O32–, Cu(CN)32–, Fe(CN)64–, Fe(CN)63–, SCN–, Au(CN)2–, Ag(CN)2–, SO42–, OCN–, SO32–, and HS– was achieved using an indirect UV detection method. The robustness of the analytical protocol was tested by analyzing ions speciation during the cyanidation of two gold sulfide‐rich ores. The 1‐h cyanidation of the two ores released up to six complexes into solution: S2O32–, Cu(CN)32–, SCN–, Fe(CN)64–, OCN–, and SO42–. The mineralogy of the ore was found to influence directly the nature and the amount of the dissolved species. Conserving the cyanidation solution for 72 h after sampling resulted in 96% total sulfur recovery. These results allow us to conclude that the analytical protocol developed in this study can become very useful for the optimization of precious‐metals cyanidation plants. 相似文献
85.
Prime Submodules and Flat Modules 总被引:2,自引:0,他引:2
A. AZIZI 《数学学报(英文版)》2007,23(1):147-152
In this paper, some characterizations of prime submodules in flat modules and, particularly, in free modules are given. Furthermore, the height of prime submodules and some saturated chain of prime submodules are also given. 相似文献
86.
An environmentally benign and efficient process for the preparation of β-hydroxysulfides was developed by a practical and simple reaction of thiols with epoxides in water catalyzed by K2CO3 in high yields and short reaction times. 相似文献
87.
There are numerous possible vectors of industrial lead poisoning in unprotected work environments and the areas surrounding industrial sites. In the Rabat-Salé region, ceramics is the industry which uses most lead. Galena (PbS) is used in the fabrication of some types of pottery, and other lead-based compounds are used as glaze. A second source of lead pollution is the production of some fuels, in which lead is used as an anti detonator. In order to evaluate the impact of lead contamination on the environment, our investigation is focused on the lead concentration in the atmosphere, soil and vegetation at five stations in the Rabat-Salé region. We found concentrations of lead higher than those published for any other country in the atmosphere and vegetation near the ceramics factories of Rabat-Salé. These concentrations decreased significantly as we moved away from urban areas. 相似文献
88.
89.
A convenient and rapid method for the electrophilic substitution reaction of indoles with carbonyl compounds has been developed by using deep eutectic solvent as green and reusable catalysts to afford the corresponding bis(indolyl) methanes in excellent yields at room temperature under mild reaction conditions. 相似文献
90.
Encapsulation of Pd(II) into superparamagnetic nanoparticles grafted with EDTA and their catalytic activity towards reduction of nitroarenes and Suzuki–Miyaura coupling
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A robust, safe and magnetically recoverable palladium catalyst was synthesized by anchoring Pd(II) onto ethylenediaminetetraacetic acid‐coated Fe3O4 (Fe3O4@EDTA) magnetic nanoparticles. The Fe3O4 magnetic nanoparticle‐supported Pd(II)–EDTA complex catalyst thus obtained was characterized using scanning and transmission electron microscopies, thermogravimetric analysis, vibrating sample magnetometry, X‐ray diffraction, and inductively coupled plasma atomic emission and Fourier transform infrared spectroscopies. Fe3O4@EDTA–Pd(II) was screened for the Suzuki reaction and reduction of nitro compounds in water. The Pd content of the catalyst was measured to be 0.28 mmol Pd g?1. In addition, the Fe3O4@EDTA–Pd catalyst can be easily separated and recovered with an external permanent magnet. The anchored solid catalyst can be recycled efficiently and reused five times with only a very slight loss of catalytic activity. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献