The pyridine-catalysed acetylation of phenols and alcohols by acetic anhydride

Abstract

Phenols are not acetylated by acetic anhydride alone in carbon tetrachloride, but addition of pyridine leads to acetylation. Alcohols, in contrast, are acetylated in the absence of pyridine, but the extent of catalysis by pyridine is less than for phenols. The fact that a maximum rate of acetylation of p-chlorophenol is reached as the pyridine concentration is increased is most readily interpreted in terms of a reaction proceeding only through a hydrogen-bonded form of the phenol.