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151.
152.
An efficient synthesis of 3-amino-2-arylimidazo[1,2-a]pyridines is described via a novel multicomponent reaction between 2-aminopyridines, benzaldehydes and imidazoline-2,4,5-trione under solvent-free conditions. 相似文献
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154.
Mateusz Pucilowski Mehdi Jangi Hesameddin Fatehi Kar Mun Pang Xue-Song Bai 《Proceedings of the Combustion Institute》2021,38(4):5597-5604
In this paper, the flame-wall interaction of reacting diesel spray under engine like conditions is investigated using large eddy simulations. The aim of this study is to understand the influence of the distance between the wall and the spray nozzle on the air entrainment rate, which is a key variable in formation/oxidation process of soot. Three experimental cases are investigated, a free jet case and two wall impingement cases with a distance from nozzle to wall of 30 mm and 50 mm, which are considered as characteristic wall impingement distances for light- and heavy-duty bores in diesel engines, respectively. The optical soot measurements imply a positive influence of wall on the rate of soot oxidation. Numerical simulations are employed to elucidate importance of different mechanisms for the air entrainment, i.e., air entrainment prior to flame lift-off position, enhanced mixing due to the wall impingement and enhanced mixing by the entrainment wave. The results show that oxidation process after the end of injection is driven by a different mixing mechanism depending on the distance to the wall. The 30 mm case resulted in a “mixing boost”, where the dominant mixing mechanism is the wall impingement vortex mixing, which gives rise to the fastest soot decay among the cases. The mixing in the 50 mm case is governed by a late wall impingement vortex mixing, giving rise to a low, but a constant air entrainment rate, i.e., a “mixing plateau”. The free jet case resulted in mixing governed by the entrainment wave mechanism. Both wall impingement cases have faster soot oxidation rate compared with the free jet case, but due to a different underlying mixing process. LES is shown to be able to replicate the line-of-sight measurements of natural OH* chemiluminescence and distribution of soot region from the optical soot diagnostics. 相似文献
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157.
Mehdi Bakavoli Alireza Motavalizadeh Kakhky Ali Shiri Mahdieh Ghabdian Abolghasem Davoodnia Hossein Eshghi Mola Khatami 《中国化学快报》2010,21(6):651-655
<正>DBUH-Br_3 catalyzed selective conversion of sulfides to sulfoxides in the presence of H_2O_2 as oxidizing agent is described.The reaction was performed selectively at room temperature and relatively short reaction times. 相似文献
158.
The effects of Mg, La and Ca promoters on primary and secondary CO_2 and H_2O formation pathways during Fischer-Tropsch synthesis on precipitated Fe/Cu/SiO_2 catalysts are investigated. The chemisorbed oxygen atoms in the primary pathway formed in the CO dissociation steps reacted with co-adsorbed hydrogen or carbon monoxide to produce H_2O and CO_2 , respectively. The secondary pathway was the water-gas shift reaction. The results indicated that the CO_2 production led to an increase in both primary and secondary pathways, and H_2 O production
decreased when surface basicity of the catalyst increased in the order Ca >Mg >La. 相似文献
159.
Eric Besson Dr. Ahmad Mehdi Prof. Arie Van der Lee Dr. Hervé Chollet Dr. Catherine Reyé Prof. Roger Guilard Prof. Robert J. P. Corriu Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(33):10226-10233
In this paper, we investigate the cation‐exchange properties of a self‐assembled hybrid material towards trivalent ions, lanthanides (La3+, Eu3+, Gd3+, Yb3+) and Fe3+. The bis‐zwitterionic lamellar material was prepared by sol–gel process from only 3‐aminopropyltriethoxysilane (APTES), succinic anhydride, and ethylenediamine. In ethanol heated under reflux, the exchange ethylenediammonium versus Ln3+ proved to be complete by complexometry measurements and elemental analyses, one Cl? ion per one LnIII remaining as expected for charge balance. In aqueous solution at 20 °C, the material was found to be selective towards lanthanide in spite of the similarity of their ionic radii. The cation uptake depends on the nature of the salt, the difference between two lanthanides reaching up to 20 % in some cases. Finally, ion‐exchange reaction with FeCl3 was chosen as a probe to get more information on the material after incorporation of trivalent ions. Based on Mössbauer spectroscopic investigations on the resulting material in conjunction with the XRD analysis of materials containing trivalent ions, a structural model was proposed to describe the incorporation of trivalent ions by exchange reaction within the original zwitterionic material. 相似文献
160.
Mehdi Barikani Hengameh Honarkar Meisam Barikani 《Monatshefte für Chemie / Chemical Monthly》2010,46(7):653-659