The pyridine-catalysed acylation of phenols by carboxylic acid anhydrides in carbon tetrachloride: Hammett, Brønsted, and Taft relationships as evidence for general base catalysis

Abstract

Rate constants for the pyridine-catalysed acylation of eight phenols by acetic anhydride in carbon tetrachloride closely follow the Hammett ρσ relationship with a positive ρ value indicating general base catalysis. Examination of additional kinetic data by means of the Brønsted and Taft relationships using different pyridines for the former and different carboxylic anhydrides for the latter confirm this mechanism.