Analysis of rate constants

Tratnyek, P.G. and Hoigne, J. Oxidation of substituted phenols in the environment a QSAR analysis of rate constants for reaction with singlet oxygen. Environ. Sci. Tecbnol., 25(9) 626-631, 1991. 

Analysis of rate constants for the bimolecular attack of substituted anilines at 308 K clearly indicated that steric effects on the nucleophile play a role. 2,6-Dimethyl- and 2,6-diethylaniline react more than an order of magnitude slower than 3,5-dimethylaniline at the same temperature (Table 7) 9 90. A comparison of the rate constants for reaction of aniline and A-methylaniline at 278 K and A-methylaniline with A-phenylaniline at 298 K provides further evidence of steric effects although the very small rate constant for the diphenylamine could, in part, also be attributed to reduced nucleophihcity due to resonance into the additional phenyl ring. 

Scherer, M. M., B. A. Balko, D. A. Gallagher, and P. G. Tratnyek, Correlation analysis of rate constants for dechlorination by zero-valent iron , Environ. Sci. Technol., 32, 3026-3033 (1998). 

Different data interpretation models have been applied simple dissociation constants (Langford and Khan, 1975), discrete multi-component models (Lavigne et al., 1987 Plankey and Patterson, 1987 Sojo and de Haan, 1991 Langford and Gutzman, 1992), discrete kinetic spectra (Cabaniss, 1990), continuous kinetic spectra (Olson and Shuman, 1983 Nederlof et al., 1994) and log normal distribution (Rate et al., 1992 1993). It should be noted that for heterogeneous systems, analysis of rate constant distributions is a mathematically ill-posed problem and slight perturbations in the input experimental data can yield artefactual information (Stanley et al., 1994). 

Such data, especially when obtained from the analysis of rate constants that have not been corrected for the double-layer influence, should be considered with care. The validity of such determinations is limited by the fact that several parameters in the applied equation (for instance, Eq. (39)) may be influenced by the nature of the solvents. 

Ifatnyek, P.G. and Holgn6, J. (1991). Qxidation of Substituted Phenols in the Environment A QSAR Analysis of Rate Constants for Reaction with Singlet Qxygen. Environ.Sci.Technol, 25,1596-1604. 

In the case of semiconductor electrodes, it is impossible to obtain the same information because the energy bands are fixed at the surface and any potential variation occurs only across the space charge layer. Here the maximum rate constant is expected if the peak of the distribution curve occurs at the lower edge of the conduction band of an n-type semiconductor. Therefore, the experimental results obtained with the modified metal electrodes, are of great importance for the quantitative analysis of rate constants from current-potential curves measured with semiconductor electrodes (see e.g. Section 7.3.4). 

The analysis of rate constants can be done using a large concentration of nucleophile (Y). Here, the observed rate constant Kots h a pseudo first-order rate constant, which can be given as... 

In this section we shall review the common practices for the presentation and analysis of rate constants for single steps of reactions. The theoretical basis of the problem has already been developed in sections 2.1 and 3.1 in... 

Fig. 4. Analysis of rate constants for the 900°C isothermal reaction between anatase and strontium carbonate. I. Kroger-Ziegler II. Dunwald-Wagner III. Zhuravlev-Lesokhin-Temperman IV. Jander V. Ginstling-Brounshtein.

Ferrer S, Tunon 1, Marti S, Moliner V, Garcia-Viloca M, Gonzalez-Lafont A, Lluch JM (2006) A theoretical analysis of rate constants and kinetic isotope effects corresponding to different reactant valleys in lactate dehydrogenase. J Am Chem Soc 128(51) 16851-16863... 

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