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91.
Magnetically recoverable AlFe/Te nanocomposite as a new catalyst for the facile esterification reaction under neat conditions 下载免费PDF全文
Seyed Jamal Alavi Hamid Sadeghian Seyed Mohammad Seyedi Hossein Eshghi Alireza Salimi 《应用有机金属化学》2018,32(3)
In this work, a new Fe3O4/AlFe/Te nanocomposite was synthesized by a one‐step sol–gel method. The Fe3O4 magnetic nanoparticles (MNPs) were prepared and then mixed with aluminum telluride (Al2Te3) in an alkali medium to produce the desired catalyst. After characterization of the Fe3O4/AlFe/Te nanocomposite by SEM, TEM, EDS, XRD, and ICP analyses, it was used in the esterification reaction. This heterogeneous catalyst showed high catalytic activity in the esterification of commercially available carboxylic acids with various alcohols to produce the desired esters at high conversions under neat conditions. The Fe3O4/AlFe/Te nanocomposites were separated from the reaction mixture via an external magnet and re‐used 8 times without significant loss of catalytic activity. 相似文献
92.
Ali Liazid Gerardo F. Barbero Miguel Palma Jamal Brigui Carmelo G. Barroso 《Chromatographia》2010,72(5-6):417-424
The development of a rapid, reliable and reproducible LC method for the determination and quantification of 13 polyphenols (gallic acid, protocatechuic aldehyde, gentisic acid, catechin, vanillinic acid, caffeic acid, vanillin, epicatechin, syringaldehyde, p-coumaric acid, ferulic acid, sinapic acid and resveratrol) in grapes and derived products is reported. The polyphenols were separated in less than 8 min. Employed was an RP-18e (100 mm × 4.6 mm) monolithic type column. A gradient method with the following solvents was utilised for the chromatographic separation: A: 90% water, 2% acetic acid in methanol, and B: 90% methanol, 2% acetic acid in water. Two detectors in series were employed: a UV–Vis detector and a fluorescence excitation/emission detector. Influence of temperature (15–40 °C) and solvent flow rate (2–5 mL min?1) on the separation were studied, and 25 °C and 2.5 mL min?1 were found to be the optimum conditions. The relative standard deviations of the resulting peak areas, for both intra- and inter- experiments, were less than 2.4 and 2.6%, respectively. Finally, the developed method has been utilised for the quantification of the polyphenols in real samples. 相似文献
93.
Ivan Malloci Jamal Daafouz Claude Iung Rémi Bonidal Patrick Szczepanski 《Nonlinear Analysis: Hybrid Systems》2009,3(3):239-250
In this article, a robust steering control for the last phase of the rolling process in a hot strip mill is proposed. This phase, called tail end phase, may be modelled as a linear switched system. The switchings make the system unstable and the task of the tail end steering control consists in guaranteeing the safety of the industrial plant. The system involves a two time scales dynamics. Hence, the singular perturbation method is used in order to design the control law. The controller has to take into account the physical variations of the rolled products and an uncertainty in the switching time. Results concerning the ArcelorMittal hot strip mill of Eisenhüttenstadt are presented. 相似文献
94.
Assist. Prof. Dr. Sumbal Saba Caio R. Dos Santos Bruno R. Zavarise Aline A. S. Naujorks Marcelo S. Franco Alex R. Schneider Marcos R. Scheide Dr. Ricardo F. Affeldt Assoc. Prof. Dr. Jamal Rafique Prof. Dr. Antonio L. Braga 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(20):4461-4466
Herein, a greener approach to the eosin Y-Na2 catalyzed, C(sp2)−H bond azo coupling of imidazoheteroarene with aryl diazonium salts is described, under acid free conditions. This direct photoredox process resulted in the corresponding azo products in good to excellent yields. Besides, this new approach could also be applicable to anilines, which is a poorly reactive substrate by other methods. The main features of this reaction are that it provides high yields and is gram-scalable and applicable to biologically relevant imidazoheteroarenes and -anilines. 相似文献
95.
AL-Jawad Selma M. H. Imran Natheer Jamal Aboud Kahlaa H. 《Journal of Sol-Gel Science and Technology》2021,100(3):423-439
Journal of Sol-Gel Science and Technology - Mn-CdS nanoflowers were successfully deposited using hydrothermal technique at 150 °C for 2 h. The effect of changing the dopant... 相似文献
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99.
Horst Böttcher Boris Mahltig Jamal Sarsour Thomas Stegmaier 《Journal of Sol-Gel Science and Technology》2010,55(2):177-185
The preparation of TiO2-coated polyester fabrics for purposes of photocatalytic water purification requires coating agents with crystalline TiO2 particles preferably in the anatase modification. The resulting coatings should exhibit a high water resistance and high
photocatalytic activity according to reaction with structurally different dyestuffs. For this, the synthesis of anatase sols
by hydrolysis of tetraisopropyltitanate in acidic medium under reflux was optimized. By precoating or addition of polymeric
epoxysilanes a good adhesion on the polyester support could be realized. The photocatalytic activity was tested with different
dyestuffs as: Methylene blue, Rhodamine B and the azo dyes AcidOrange 7 and C.I. Reactive red 158. The rate of photodestruction
depends strongly on the type of used dye and its structure. Surprisingly, no differences in photodegradation were found in
case of investigations with Rhodamine B, if the photoreaction is performed under exposure with UV or with visible light. A
possible explanation of the similar behavior of photoreaction under different light sources could be a photodestruction by
electron transfer from Rhodamine B to TiO2. Therefore, Rhodamine B seems to be generally not suitable for the evaluation of the photoactivity of TiO2 under irradiation with visible light. 相似文献
100.
Paul P. Horley Vítor R. Vieira Peter M. Gorley Vitalii K. Dugaev Jamal Berakdar Józef Barna? 《Journal of magnetism and magnetic materials》2010,322(9-12):1373-1376
One of the important requirements for spintronic devices concerns an efficient magnetization reversal, which may eventually lead to ultra-fast non-volatile magnetic memory applications. In particular, it is necessary to achieve stable sub-nanosecond switching times and to reduce magnetization “ringing”, so that the reversal will proceed along the shortest ballistic path connecting the initial and the target magnetization states. This paper is dedicated to the numerical simulations of a mono-domain ferromagnetic particle, described by the Landau–Lifshitz–Gilbert equation. We study the general case of arbitrary orientation of the applied field/current pulses, constructing dynamic diagrams for the reversal time. We have found that even short 50 ps pulses, applied at a proper angle, will induce magnetization reversal with minimal ringing effects. 相似文献