Solvent nucleophilicity power plots

With tosylate solvolysis rates available for the first time in trifluoroacetic acid, Peterson and Waller (4) noted that plots of log k versus the ionizing power, Y, for the solvolysis of methyl, ethyl and secondary tosylates showed deviations from linearity that could be attributed to solvent nucleophilicity. 

Fig. 10 Solvent effects on the solvolysis rates of 37 obtained at 50°C as plotted against solvent ionizing power 7oxs (a) and nucleophilicity A x (b). Taken from Ref. 76.

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