comprehensive study of the Pseudo-first order rate constants K-0 (sec(-1)) for uncatalysed reaction and the thermodynamic parameters for alkyl formates HCOOR in neutral medium in the temperature range (293-343 K) has been undertaken The fi ee energies, enthalpies and entropies of activation were measured according to the theory of absolute reaction rates. The enthalpies and entropies of activation decreased from methyl to ethyl formates whereas the DeltaS(#) and DeltaH(#) values obtained for isopropyl formate were approximately the same as that for ethyl formate indicating that further substitution at the proportional to -C atom did not produce any further significant intramolecular polarization. The A(AL)1 mechanism was operative in neutral hydrolysis of esters.