Correlation of the rates of solvolysis of benzoyl chloride and derivatives using extended forms of the Grunwald–Winstein equation

Available specific rates of solvolysis at 25 °C of benzoyl chloride and four para ‐substituted derivatives for which both N T and Y Cl values are tabulated were analyzed using the extended (two‐term) Grunwald–Winstein equation. The ionization pathway with appreciable nucleophilic solvation of the incipient carbocation observed for the p ‐methoxy derivative is accompanied by increasingly important regions of dominant operation of an addition–elimination pathway as the Hammett σ value for the substituent increases. Accordingly, for the p ‐nitro derivative only the 97% HFIP data point deviates from the addition–elimination correlation. Correlations of the specific rates of solvolysis of 2,6‐dimethylbenzoyl chloride are improved by incorporation of a term governed by the aromatic ring parameter ( I ). Copyright © 2002 John Wiley & Sons, Ltd.