Reactions of carbonyl compounds in basic solutions. Part 33. 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

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 a nd activation parameters demonstrate relatively rapid hydrolysis via neighb ouring group participation by the acyl-carbonyl group in the ester hydrolys is and slower hydrolysis via intramolecular fission of the adducts in the b enzoate anion hydrolysis. The pK(a) values of the corresponding benzoic aci ds have been measured in water and their ring-chain tautomeric equilibrium constants determined.