Reactions of carbonyl compounds in basic solutions. Part 33.1 Effect of 2-trichloro- and tribromoacetyl substituents on the alkaline hydrolysis of methyl benzoate, as well as the hydrolysis of the corresponding benzoate anions and ionisation/ring–chain tautomerism of the corresponding acids

Abstract

Rate coefficients have been measured for the alkaline hydrolysis of methyl 2-trichloro- and tribromoacetylbenzoate, as well as the alkaline hydrolysis of the corresponding 2-trichloro- and tribromobenzoate anions, in 30% (v/v) dioxane–water at several temperatures. The relative rates of hydrolysis and activation parameters demonstrate relatively rapid hydrolysis via neighbouring group participation by the acyl-carbonyl group in the ester hydrolysis and slower hydrolysis via intramolecular fission of the adducts in the benzoate anion hydrolysis. The pKa values of the corresponding benzoic acids have been measured in water and their ring–chain tautomeric equilibrium constants determined.