Temperature-dependent kinetics

Davis DD, Machado G, Conaway B, et al. 1976. A temperature dependent kinetics study of the reaction of OH with CHCI, CHCK CHClsand CHsBr. J Chem Phys 65 1268-1274. 

In the literature there are no quantitative studies on the kinetics and thermodynamics of stoichiometric superoxide reactions with metal centers in general, and metalloporphyrins in particular. More precisely, superoxide concentration and temperature dependent kinetic and thermodynamic measurements were never reported and consequently the rate constants, activation parameters or binding constants for this t5rpe of reactions (Scheme 15) are not known. (The catalytic rate constants for the superoxide disproportionation, i.e., dismutation, by metal complexes are known (see earlier), however in those measurements the concentration of a catalytic amount... 

Although, the first reaction step, reduction of the Fe(III) to the Fe(II) porph5rrin complex by KO2, could not be studied in detail because of interference of the formation of the Fe(III) hydroxo species, the second reaction step, binding of superoxide to the Fe(II) species and formation of the Fe(III)-peroxo complex, could be studied in detail 61). To our knowledge, for the first time superoxide concentration (Fig. 11) and temperature dependent kinetic studies of reactions with superoxide have been performed by stopped-fiow UVA is measurements, and as a result the second-order rate constant ( on = 36,500 + 500 s )... 

Eberhard, J., and C. J. Howard, Temperature-Dependent Kinetics Studies of the Reactions of C2H502 and /t-C3H702 Radicals with NO, hit. J. Chem. Kinet., 28, 731-740 (1996). 

Results of a study of the mechanism and temperature-dependent kinetics of the dehydration of hot compressed liquid water do not corroborate an earlier claim that isobutene formation is catalysed by dissociation of BtfOH at 250 °C.21... 

Davis, D.D., Machado, G., Conaway, B., Oh, Y., Watson, R. (1976) A temperature dependent kinetic study of reaction of hydroxyl radicals with chloromethane, dichloromethane, trichloromethane and bromomethane. J. Chem. Phys. 65, 1268-1274. 

There are limited temperature dependence studies of reactions of elemental mercury with atmospheric oxidants (e.g., with O3, HO, Br and Cl). Some reactions are expected to have slight temperature dependence and hence the data can be directly used for wide range of atmospheric temperature. However, some others can exhibit stronger temperature dependence. We hence require temperature dependence kinetic data that can reflect the general conditions in the troposphere. We thus recommend strongly to have the available data over a wide range of temperatures. 

The low-temperature kinetics data of these early difficult experiments did not have the time or spectral resolution to consider these possibilities. However, there is now an excellent set of temperature-dependent kinetics data for the similar bacterium Rp. viridis [16, 17]. These data clearly show multiphasic kinetics that can be resolved into very fast, fast and slow phases, most of which slow with temperature roughly an order of magnitude before reaching a temperature-independent plateau. What does change dramatically with temperature is the contribution of each of these phases, with the fast phases falling away dramatically at a temperature around 210 K for the wild-type Rp. viridis. Thus, the overall result is a dramatic decrease in half-time of the reaction with temperature, as Devault and Chance observed. 

How should you process the coefficients of the polynomial, which are determined from the regression analysis, to calcnlate the temperature-dependent kinetic and equilibrium constants ... 

The temperature-dependent kinetic and equilibrium constants, which can be determined from total pressure dependence of the initial reactant-product conversion rate, are... 

The isosteric heat of adsorption Qiso(9) is related to the (differential) potential energy V( ) of the adsorbate on the surface and the (temperature dependent) kinetic degrees of freedom/in the adsorbed and the 3D gas phase, respectively ... 

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