Bronsted-Evans-Polanyi relationship

Other methods for calculating the activation energies of the ORR have been reported in the literature. Based on the linear Bronsted-Evans-Polanyi relationship, Norskov et al. [85] proposed a method to estimate the least activation energy by calculating the stability of the reaction intermediate. With this simple model, the study reported a Tafel slope of 60 mV at 300 K (71 mV at 357 K). The value was consistent with experimental results. 

Scaling Relations for Transition States The Bronsted-Evans-Polanyi Relationship... 

Bronsted-Evans-Polanyi (BEP) linear activation energy-reaction energy relationships ... 

Apparently, these results implied an inverse relationship between reactivity and selectivity, with the reactivity of the carbocation measured by the inverse of the rate constant for solvolysis. This indeed was not unexpected in the context of a general perception that highly reactive reagents, especially reactive intermediates such as carbocations, carbanions, or carbenes are unselective in their reactions.257 259 Such a relationship is consistent with a natural inference from the Hammond postulate258 and Bell-Evans-Polanyi relationship,260 and is illustrated experimentally by the dependence of the Bronsted exponent for base catalysis of the enolization of ketones upon the reactivity of the ketone,261,262 and other examples21,263 including Richard s careful study of the hydration of a-methoxystyrenes.229... 

A First Approximation The Evans-Polanyi Model of the Bronsted Law and Other Linear Free-Lnergy Relationships... 

Making use of the relationship between thermodynamics and kinetics (Evans-Bronsted-Polanyi relationship), it can be written that... 

The relationship between rates and equilibria was first proposed by Bronsted and Pedersen (1924) and subsequently treated by Bell (1936) and Evans and Polanyi (1938) it is shown in (108). Some 30 years ago Leffler (1953) provided (108) with a molecular basis by suggesting that the parameter a reflects... 

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