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Multistep Reactions (multistep + reaction)
Selected AbstractsChemInform Abstract: Platinum-Catalyzed Multistep Reactions of Indoles with Alkynyl Alcohols.CHEMINFORM, Issue 4 2008Sivakolundu Bhuvaneswari Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Generalized treatment of NMR spectra for rapid chemical reactionsCONCEPTS IN MAGNETIC RESONANCE, Issue 4 2007Matthew D. Christianson Abstract Application of NMR spectroscopy to fast irreversible reactions (t1/2 < 0.7 s) has been hampered by limitations in instrumentation and general methods for modeling the complicated spectra that result. Analytical descriptions of nuclear spin dynamics during fast reactions, first solved by Ernst and coworkers, are limited to first-order reaction kinetics. We demonstrate that numeric methods enable simulation of NMR spectra for fast reactions having any form of rate law. Simulated stopped-flow NMR spectra are presented for a variety of common kinetic scenarios including reversible and irreversible reactions of first and second-order, multistep reactions, and catalytic transformations. The simulations demonstrate that a wealth of mechanistic information, including reaction rates, rate laws, and the existence of intermediates, is imbedded in a single NMR spectrum. The sensitivity of modern NMR instrumentation along with robust methods for simulating and fitting kinetic parameters of fast reactions make stopped-flow NMR an attractive method for kinetic studies of fast chemical reactions. © 2007 Wiley Periodicals, Inc. Concepts Magn Reson Part A 30A: 165,183, 2007. [source] Investigation of solid,gas reaction heat transformer system with the consideration of multistep reactionsAICHE JOURNAL, Issue 9 2008C. Wang Abstract The performance of solid,gas reaction heat transformer system using MnCl2 and CaCl2 was investigated with the consideration of multistep reactions between CaCl2 and NH3. The reactions between CaCl2 and NH3 could be CaCl2·2/4NH3 and CaCl2·4/8NH3. The simulated results were verified by the experimental data. From the analysis results, it was concluded that the two reactions between CaCl2 and NH3 existed simultaneously. The favored conditions for the simultaneous occurrence of multistep reactions were discussed. The main reaction in the system with the initial state of CaCl2·2NH3 and CaCl2·4NH3 were designated as the reaction of CaCl2·2/4NH3 and CaCl2·4/8NH3, respectively. It was concluded that high driving temperature TM, large relative gas volume, and large specific heat transfer area were the favored conditions for the simultaneous occurrence of multistep reactions in the systems both with the initial state of CaCl2·2NH3 and CaCl2·4NH3. High initial charging pressure P0 was favored for the system with the initial state of CaCl2·2NH3, while low P0 was favored for the system with the initial state of CaCl2·4NH3. The impacts of the simultaneous occurrence of multistep reactions on the system performance indicators [temperature lift, specific power, and system coefficient of performance (COP)] were also investigated in this article. It was concluded that the occurrence of the reaction of CaCl2·4/8NH3 for the initial state of CaCl2·2NH3 led to better system performance, i.e., larger temperature lift, larger specific power, and larger system COP. However, the occurrence of the reaction of CaCl2·2/4NH3 for the initial state of CaCl2·4NH3 would lead to lower specific power. The temperature lift and system COP were larger for the initial state of CaCl2·4NH3; while the cycle period was shorter for the initial state of CaCl2·2NH3. © 2008 American Institute of Chemical Engineers AIChE J, 2008 [source] | ||||||||||