Results 271 to 280 of about 1,664,923 (355)

Rate constants for silylene reactions

Research on Chemical Intermediates, 1990
It is only since 1985 that the absolute rate constanss have been measured for some reactions of divalent silylene species. In this article the absolute rate constant data reported to date for the reactions of SiH2, SiMe2, SiMePh, SiHCl, SiCl2, SiF2 and SiBr2 are reviewed and, where possible, mechanistic pathways discussed.
I. Safarik, V. Sandhu, E. M. Lown, O. P. Strausz, T. N. Bell   +4 more
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On reaction rate constants and rate kernels

Chemical Physics Letters, 1978
Abstract A simple model for a reversible isomerization reaction A ⇋ B is used to show how rate constants and their time-dependent generalizations can be related to microscopic reactive steps and nonreactive internal dynamics (e.g., vibrational relaxation).
Scott H. Northrup, James T. Hynes
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Rate Constants for Anilidyl Radical Cyclization Reactions

The Journal of Organic Chemistry, 2005
[reaction: see text] N-Aryl-5,5-diphenyl-4-pentenamidyl radicals (3) were produced by 266 nm laser-flash photolysis of the corresponding N-(phenylthio) derivatives, and the rate constants for the cyclizations of these radicals were measured directly. The 5-exo cyclization reactions were fast (k(c) > 2 x 10(5) s(-1)), and radicals 3 generally behaved as
E, Martinez, M, Newcomb
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Absolute Rate Constants for Iminyl Radical Reactions

The Journal of Organic Chemistry, 1997
The kinetics of cyclization of the 2-methyl-6,6-diphenyl-5-hexeniminyl radical (3) were measured by laser flash photolysis methods from 0 to 50 degrees C, and the kinetics of trapping of radical 3 by thiophenol and p-chlorothiophenol were determined between 4 and 83 degrees C by indirect methods using the unimolecular rate constants as the basis values.
Marie-Helene, Le Tadic-Biadatti, Anne-Claude, Callier-Dublanchet, John H., Horner, Béatrice, Quiclet-Sire, Samir Z., Zard, Martin, Newcomb   +5 more
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Rate constants for aminyl radical reactions

Tetrahedron Letters, 1993
Abstract Rate constants for cyclization of the N -methyl-5,5-diphenyl-4-pentenaminyl radical ( 4 ) and for reaction of this radical with t -BuSH were determined by direct methods.
Martin Newcomb, John H. Horner, Haifa Shahin   +2 more
openaire   +1 more source

Absolute Rate Constants for α-Amide Radical Reactions

The Journal of Organic Chemistry, 1998
The 1-(diethylcarbamoyl)-6,6-diphenyl-5-hexenyl radical (4a), the 1-(diethylcarbamoyl)-7,7-diphenyl-6-heptenyl radical (4b), and the 1-(diethylcarbamoyl)-1-methyl-6,6-diphenyl-5-hexenyl radical (4c) were produced from the corresponding PTOC esters (anhydrides of the carboxylic acid and N-hydroxypyridine-2-thione) by laser flash photolysis methods.
Osama M., Musa, Seung-Yong, Choi, John H., Horner, Martin, Newcomb   +3 more
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Determination of Rate Constants for Rapid Peroxidase Reactions

Analytical Biochemistry, 1995
We describe an improved enzyme-monitored stopped-flow method for determining rate constants for peroxidase reactions that are too rapid to measure by conventional pseudo-first-order methods. Ascorbate will reduce many substrate radicals as rapidly as they are generated by a peroxidase.
D C, Goodwin, I, Yamazaki, S D, Aust, T A, Grover   +3 more
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Calculating Rate Constants in Forward Drug Transfer Reactions

Journal of Pharmaceutical Sciences, 1973
A simple method for obtaining and processing drug transfer data derived from in vitro model cells such as the Schulman cell is presented. Simplified calculation procedures are developed for determining the rate constants that describe the transfer of the drug through the compartments. Transfer of the acidic drug salicylic acid from a pH 2.0 compartment
W O, Thompson, S T, Christian
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The Reaction Rate Constant of Chlorine Nitrate Hydrolysis

Chemistry, 2001
The first-order rate constant for the decomposition of chlorine nitrate (ClONO2) by water in a cyclic 1:3 complex at stratospheric temperatures is shown to be close to the values for the hydrolysis rate coefficient of chlorine nitrate on an ice surface determined in the laboratory.
T, Loerting, K R, Liedl
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Quantum mechanical rate constants for bimolecular reactions

The Journal of Chemical Physics, 1983
Several formally exact expressions for quantum mechanical rate constants (i.e., bimolecular reactive cross sections suitably averaged and summed over initial and final states) are derived and their relation to one another analyzed. It is suggested that they may provide a useful means for calculating quantum mechanical rate constants accurately without ...
William H. Miller, Steven D. Schwartz, John W. Tromp   +2 more
openaire   +1 more source