Bronsted equation extended

Thus it is necessary to pay due attention to the rate constant term, in addition to the concentration factor, if the adequate explanation of the polyelectrolyte influence on chemical reactions is sought. As has been mentioned in the present paper, the polyelectrolyte influence was accounted for in terms of the rate constant change by using the Bronsted equation. Because of the limitation of the Bronsted equation, quantitative discussion was restricted to small influence of polyelectrolyte (as seen from the deceleration effect on the ammonium cyanate-urea conversion). One of the most important future problems in this field is to extend the Bronsted equation to account for such huge polyelectrolyte influences as described above. 

Using a Bronsted equation in which the ionic strength term has been derived from an extended Debye-Huckel correlation, it has been shown that for the ions M+ = Li+, Na+, K+, Rb+, or Cs+ the first (Ati) pathway is operative but only in the case of Li+ to an appreciable extent. For the cations Li+ or Na+, the Arg route is operative whereas for K+, Rb+, or Cs+ the reaction proceeds via the kt mechanism, the rate constants extrapolated to zero ionic strength being remarkably similar. 

Streitwieser and co-workers have extended their measurements of equilibrium acidities in cyclohexylamine to determination of exchange rates.69 They have made quantitative correlations between exchange rate and the pKa s determined by equilibrium methods for various aromatic compounds and have thus been able to verify that the Bronsted relation holds for these substances and to find Bronsted coefficients a for various types of compounds. A third method for evaluating p/Ca of weak acids, which has been used by Applequist70 and by Dessy,71 involves the study of exchange reactions of organometallic compounds (Equations 3.54 and 3.55). 

FIGURE 6. Extended Bronsted plot of ogkH+ vs pK%H for the protonation of some highly activated alkenes RC(X)=CH2, R = H, CH3, Ph see equations 55 and 56 in text, as well as Table 16. The squares represent alkenes with / -substituents these were not included in the correlation... 

Thus Pf, Pl and p uc refer to forward reactions and p, P and ptg refer to their microscopic reverse. Figure 9 illustrates the extended Bronsted relationship for the reaction of Equation (41) when the leaving group basicity is varied. Unlike the case of proton transfer the values p c or PLg are not the same as the Leffler a. Moreover the value of the Pl, is quoted with its sign unlike that of the Bronsted or Leffler a. 

The extended Bronsted correlation for the aminolysis of the 2,4,6-trinitrophenyl ester is linear with an equation ... 

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