Br nsted coefficient

These equations are called Br nsted relationships and the parameters a and p are Br nsted coefficients. 

Catalytic Coefficients, Br nsted Coefficients and Acidities for the Halogenation of Various Carbonyl Compounds"... 

Br nsted Coefficients and Catalytic Coefficients for Various Vinyl Ethers"... 

Br nsted coefficients, aA, obtained by a plot of kinetic acidity dependence against thermodynamic acidity dependence and 03, obtained by a plot of rate of hydrogen exchange of the aromatic substrates against substrate pAa. 

Br nsted Coefficients for the Acid Catalysed Nucleophilic Addition of Various Nucleophiles to Acetaldehyde... 

Br nsted Coefficients and Rate Constants for Elimination from Alkyl bromides0... 

The preceding discussion has suggested that a (or 0) may be considered a measure of transition state structure even if the expected reactivity-selectivity relationship is not observed. There is, however, strong evidence to suggest that the Br nsted coefficient does not always reflect the degree of proton transfer in the transition state. 

In conclusion, it is apparent that the use of the Br nsted coefficient as a measure of selectivity and hence of transition state structure appears to be based on extensive experimental data. However, the many cases where this use of the Br nsted coefficient is invalid suggest that considerable caution be used in drawing mechanistic conclusions from such data. The limitations on the mechanistic significance of a require further clarification, but the first steps in defining them appear to have been taken. The influence of change in the intrinsic barrier and variable intermolecular interactions in the transition state, both of which will result in a breakdown of the rate-equilibrium relationship, as well as internal return appear to be some of the key parameters which determine the magnitude of the Br nsted coefficient in addition to the degree of proton transfer. 

The Br nsted coefficient is generally obtained from the slope of a plot of log b versus pAfa. Variations in pK3 are usually brought about by changes in substituents in the base (acid) moiety. An alternative manner of effecting variation in pKa, would be by changes in the reaction medium, as described in the previous section. The question arises, however, as to the equivalence of the two methods. 

Bom-Oppenheimer approximation, 193 Br nsted acid catalysis, 265 Br nsted base catalysis, 265 Br nsted coefficient, 225, 345, 347 Br(<nsted plot, 346 Br nsted relationships, 345 Brj nsted-type plot, 350 curved, 351 Buffer, 24... 

Here, a is the so-called transfer coefficient, or Br nsted coefficient, whose value lies between 0 and 1, and the subscript "o has been used to denote the constants for one of the reactions conditionally chosen as a standard. 

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