Reaction influence

If the kinetics of single reactions is reliably determined by a separate study, it is possible on this basis to ascertain how single reactions influence... 

It is appropriate to emphasize again that mechanisms formulated on the basis of kinetic observations should, whenever possible, be supported by independent evidence, including, for example, (where appropriate) X-ray diffraction data (to recognize phases present and any topotactic relationships [1257]), reactivity studies of any possible (or postulated) intermediates, conductivity measurements (to determine the nature and mobilities of surface species and defects which may participate in reaction), influence on reaction rate of gaseous additives including products which may be adsorbed on active surfaces, microscopic examination (directions of interface advance, particle cracking, etc.), surface area determinations and any other relevant measurements. 

Two major questions regarding the applicability of this system remain to be discussed. First, how representative Is the catalyst sample In the mlnlreactor of the catalyst In the pilot plant And second, how does the Interruption of the reaction Influence kinetic behavior ... 

The Nature of the Reactive Intermediate Involved in the Alkylation Reaction Influences Atom Site Selectivity... 

The rate constants of these reactions were found to be very close kA = 2.0 x 10 5 s 1 and kis = 2.2x 10 5 s 1 (//-nonane, 403 K). The competition between homolytic and heterolytic reactions influences the effectiveness of initiation. When the heterolytic isomerization of... 

Heat effects accompanying chemical reaction influence equilibrium constants and compositions as well as rates of reaction. The enthalpy change of reaction, AHr, is the difference between the enthalpies of formation of the participants. It is positive for endothermic reactions and negative for exothermic ones. This convention is the opposite of that for heats of reaction, so care should be exercised in applications of this quantity. Enthalpies of formation are empirical data, most often known at a standard temperature, frequently at 298 K. The Gibbs energies of formation, AGfl likewise are empirical data. 

We shall also encounter situations where a chemical reaction influences the concentrations. For a volume reaction of the type j - i, the reaction rate for the production of i is given by k(Cj (if we assume it to be an elementary reaction), where k is the forward reaction rate constant, and the rate of consumption of i by a term where kb is the rate constant of the backward... 

When a reaction influences the rate of some other reaction which does not occur under ordinary conditions, the phenomenon is called induced catalysis. For example... 

It is not the purpose of the present review to give a critical appraisal of the Kurz approach that can be found in the review by Kraut (1988). Rather, it is to show how this simple method can be used in the study of reactions influenced by cyclodextrins. Some examples involving catalysed... 

III. Metal-catalyzed esterification and alcoholysis reactions Influence of the structure of the reactants and of the nature of the reaction medium,J. Polym. Sci., Polym. Chem. Ed., 27, 3535-3550 (1989). 

For some volatile solutes, slow reactions influence the rate of equilibration between the gas and liquid phases. Generally the rate of gas transfer across the liquid-gas interface is the rate-limiting step, as discussed in Section 3.4. But there may also be slow hydration or other reactions in solution that must be allowed for. An important example is the hydration of CO2, whose half-life may be comparable to rates of transfer of CO2 across the air-water interface. 

These results show that the observed activation energy for reactions influenced by strong pore resistance is approximately one-half the true activation energy. 

The kinetic theory of collisions, which has been so effective in developing the kinetics of vapor-phase reactions, has substantially influenced research on the processes of liquid-phase oxidation and in describing these processes. It has been thought that the lack of laws on which to base liquid-state theory (in contrast to the well-developed kinetic theory of gases) would in principle severely limit the development of a quantitative theory of liquid-phase reactions. At present the characteristics of the liquid state are carefully considered in discussing the mechanism of intermolecular reactions, influence of the medium on reactivity of compounds, etc. 

Relation of heat of activation to heat of reaction. Influence of homogeneous catalysts on the heat of activation and on the position of equilibrium. 

Comparison of Homogeneous and Catalysed Reactions. Influence of the Catalyst on the Heat of Activation. 

Reactions influenced by mass transport If the rate of a reaction is influenced by mass transport, the effect of the pressure both on the rate of the chemical reaction and on the rate of mass transport must be taken into account. As an example, a heterogeneous catalytic reaction governed by the rate of diffusion within the pores of the catalyst is considered. 

Selectivity in Catalytic Reactions Influenced by Mass and Heat Transfer Effects... 

There are some difficulties with testing this experimentally. The first is that it is not easy to match the same set of bases to electrophiles of quite different reactivity. A second is that the most readily available equilibrium constants characterizing the nucleophiles are pAias of the conjugate acids, which do not necessarily correlate reactivities toward carbocations. Thirdly, one should avoid reactions influenced by diffusion control. Finally, care has to be taken with steric and solvent effects. 

Interestingly, the nature of the thiol (GSH vs other thiols) that is used to trigger the reaction, influences to some extent the pathways that are subsequently taken (Povirk and Goldberg 1985b, 1986). NCS may also be activated by C02 (Favaudon et al. 1985). Here, three C02- are required for an activation, and the preferred site of attack is now HI. ... 

Ruppert, G., Bauer, R., Heisler, G., Novalic, S. (1993) Mineralization of cyclic organic water contaminants by the photo-Fenton reaction-influence of structure and substituents. Chemosphere 27(8), 1339-1347. 

If there is a marked deviation from a straight line on plotting log k and l/T, then it gives an indication that the observed reaction is a composite one made up of two or more concurrent reactions influenced by one of the reactions and it may predominate, so that the slope of the curve corresponds to the value of E proper to this reaction. 

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