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排序方式: 共有610条查询结果,搜索用时 15 毫秒
61.
Our own work on steroid compounds with defined conformation as chiral model compounds for investigations of chemo-, regio- and stereoselectivity of metal-mediated new reactions is reviewed. Reactions with nickelacycles, (π-allyl)zirconoxycarbene complexes, iron tricarbonyl complexes of dienes and 1-azadienes, the Ru-catalyzed synthesis of 1,3-dihydropyrrol-2-ones from 1-azadienes, the Pd-catalyzed cyclopropanation of 1-azadienes, syntheses with cuprio steroids, copper complexes of amino alcohol derivatives and the copper-mediated hydroxylation of nonactivated C-H bonds with molecular oxygen are discussed. 相似文献
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Gabrieli L. ParrilhaAuthor VitaeRafael P. VieiraAuthor Vitae Anayive P. RebolledoAuthor VitaeIsolda C. MendesAuthor Vitae Lidia M. LimaAuthor VitaeEliezer J. BarreiroAuthor Vitae Oscar E. PiroAuthor VitaeEduardo E. CastellanoAuthor Vitae Heloisa BeraldoAuthor Vitae 《Polyhedron》2011,30(11):1891-1898
Complexes [Zn2(HL1)2(CH3COO)2] (1) and [Zn2(L2)2] (2) were synthesized with salicylaldehyde semicarbazone (H2L1) and salicylaldehyde-4-chlorobenzoyl hydrazone (H2LASSBio-1064, H2L2), respectively. The crystal structure of (1) was determined. Upon recrystallization of previously prepared [Zn2(HL2)2(Cl)2] (3) in 1:9 DMSO:acetone crystals of [Zn2(L2)2(H2O)2]·[Zn2(L2)2(DMSO)4] (3a) were obtained. The crystal structure of 3a was also determined. All crystal structures revealed the presence of phenoxo-bridged binuclear zinc(II) complexes. 相似文献
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Mario Llano-RestrepoAuthor Vitae Y. Mauricio Muñoz-MuñozAuthor Vitae 《Fluid Phase Equilibria》2011,307(1):45-57
Due to the economics of the ethylene market and the subsidized production of fermentation-based ethanol in some countries, use of the ethylene hydration process to make ethanol has been steadily declining. The economics of this process might improve by combining the reaction and separation in a reactive distillation column, whose conceptual design requires a study of the combined chemical and phase equilibrium (CPE) of the reacting system. In this work, the Peng-Robinson-Stryjek-Vera equation of state was combined with the UNIQUAC activity coefficient model through the Wong-Sandler (WS) mixing rules in order to correlate the available experimental data for the vapor-liquid equilibria (VLE) of the ethylene-water, ethylene-ethanol, and ethanol-water binary systems at 200 °C. The interaction energies of the UNIQUAC model and the binary interaction coefficient of the WS mixing rules were used as the fitting parameters. From the optimum values of these parameters, both the VLE and the combined CPE of the ethylene-water-ethanol ternary system were predicted at 200 °C and various pressures. At this temperature, the catalytic activity of a H-pentasil zeolite has already been reported to exhibit a maximum for ethylene hydration, and also the experimentally measured two-phase region of the ternary system is sufficiently wide. By means of the reactive flash method, the chemical equilibrium compositions of the liquid and vapor phases were determined for several pressures, and the equilibrium conversion and the vapor fraction were calculated as functions of the ethylene to water feed mole ratio. It turns out that the vapor-liquid mixed-phase hydration of ethylene achieves equilibrium conversions much higher than those computed for a vapor-phase reaction that would hypothetically occur at the same conditions of pressure and feed mole ratio. It was found that the reactive phase diagram of the ternary system exhibits a critical point at 200 °C and 155 atm. 相似文献
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Molla R. IslamAuthor Vitae Zhenzhen LuAuthor VitaeXue LiAuthor Vitae Avijeet K. SarkerAuthor VitaeLiang Hu Paul ChoiXi Li Narek HakobyanMichael J. Serpe 《Analytica chimica acta》2013
Stimuli-responsive polymers are capable of translating changes in their local environment to changes in their chemical and/or physical properties. This ability allows stimuli-responsive polymers to be used for a wide range of applications. In this review, we highlight the analytical applications of stimuli-responsive polymers that have been published over the past few years with a focus on their applications in sensing/biosensing and separations. From this review, we hope to make clear that while the history of using stimuli-responsive polymers for analytical applications is rich, there are still a number of directions to explore and exciting advancements to be made in this flourishing field of research. 相似文献
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Hélène Pellissier Author Vitae 《Tetrahedron》2007,63(16):3235-3285