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 pK_a values of the corresponding benzoic acids have been measured in water and their ring–chain tautomeric equilibrium constants determined.