Kinetic electrolyte effect

Although these effects are often collectively referred to as salt effects, lUPAC regards that term as too restrictive. If the effect observed is due solely to the influence of ionic strength on the activity coefficients of reactants and transition states, then the effect is referred to as a primary kinetic electrolyte effect or a primary salt effect. If the observed effect arises from the influence of ionic strength on pre-equilibrium concentrations of ionic species prior to any rate-determining step, then the effect is termed a secondary kinetic electrolyte effect or a secondary salt effect. An example of such a phenomenon would be the influence of ionic strength on the dissociation of weak acids and bases. See Ionic Strength... 

MICROTUBULE ASSEMBLY KINETICS KINETIC ELECTROLYTE EFFECT IONIC STRENGTH KINETIC EQUIVALENCE KINETIC AMBIGUITY KINETIC HALDANE RELATIONSHIPS HALDANE RELATIONSHIPS... 

Since an equilibrium is assumed between the transition state and the reactant(s), and because the corresponding equilibrium constant can be expressed in terms of activity coefficients and concentrations to account for the non-ideality of the medium, it follows that there should be an activity coefficient effect upon reaction rates. This is observed as a dependence of the rate constant upon ionic strength - the kinetic electrolyte effect [2]. Thus, for a bimolecular reaction,... 

Kinetic electrolyte effects are usually (too restric-tively and therefore incorrectly) referred to as kinetic salt effects. ... 

A kinetic electrolyte effect ascribable solely to the influence of the ionic strength on activity coefficients of ionic reactants and transition states is called a primary kinetic electrolyte effect. A kinetic electrolyte effect arising from the influence of the ionic strength of the solution upon the pre-equilibrium concentration of an ionic species that is involved in a subsequent rate-limiting step of a reaction is called a secondary kinetic electrolyte effect. A common case encountered in practice is the effect on the concentration of a hydrogen ion (acting as catalyst) produced from the ionization of a weak acid in a buffer solution. 

Hsueh KL, Gonzalez ER, Srinivasan S. 1983. Electrolyte effects on oxygen reduction kinetics at platinum—A rotating-ring disk electrode analysis. Electrochim Acta 28 691-697. 

Second-order rate coefficients for reaction (21) (X = I and OAc) were also reported by Abraham and Behbahany30 and are given in Table 20. Kinetic salt effects of added tetra-n-butylammonium perchlorate were studied for reaction (21) (X = I and OAc) both with solvent methanol and solvent tert.-butanol. Reaction (21) (X = 1) was accelerated in both solvents to about the same extent as was reaction (21) (X = Cl), and mechanism SE2(open) was therefore suggested. The reaction of tetraethyltin with mercuric acetate was subject to very large positive salt effects in methanol, perhaps due to anion exchange, but was unaffected by the electrolyte in solvent /er/.-butanol. Abraham and Behbahany30 considered that it was not possible to deduce the mechanism of the acetate reaction and that further work was necessary to decide between mechanism SE2(open) and mechanism SE2(cyclic). 

The interpretation of the kinetic salt effect in aqueous solutions is based on the theory of strong electrolytes, but the latter can only be applied to ammonia solutions of uni-univalent salts at concentrations lower by a factor of 106 than the concentrations employed in the above experiments (Pleskov, 1937). It follows that the existing quantitative theory cannot be used to interpret the results obtained. 

When the source of the catalytically active hydrogen ion is a weak acid, one has to consider the weak electrolyte equilibrium involved and the change of the dissociation constant with electrolyte concentration, medium, and temperature. Br0nsted (7) termed this phenomenon secondary kinetic salt effect, but the writer would prefer to omit the word kinetic and substitute electrolyte for salt. The understanding of these... 

The rate constants of chemical reactions the yield and the selectivity of a reaction, as well as the conditions for refining or recycling of products can be optimized by the choice of appropriate solvents. Discussion in this section is restricted to reaction mechanisms involving electrolytes or single ions. The role of electrolyte solutions in primary and secondary kinetic salt effects is not considered. For this problem see Refs. s. 

Temperature differences which affect electrolyte conductivity and electrode kinetics Edge effects... 

Yamada, Y. Itiyama, Y. Abe, T Ogumi, Z. Kinetics of lithium ion transfer at the interface between graphite and liquid electrolyte effects of solvent and surface film, Langmuir 2009, 25, 12766-12770. 

Yamada, Y Iriyama, Y Abe, T. Ogumi, Z., Kinetics of Lithium Ion Transfer at the Interface between Graphite and Liquid Electrolytes Effects of Solvent and Surface Film. Langmuir 2009, 25, 12766-12770. 

Use of deuterium in the mechanistic studies of the HER began shortly after its discovery in 1931. It was used in two directions (a) as a tracer to measure the unidirectional component rate of the reaction, and (b) for examination of the kinetic isotope effect, namely, the electrolytic separation factor. 

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