Kinetics of the Acid Hydrolysis of Di-2, 4-Dichlorophenyl Phosphate

School of Post-graduate Studies and Research in Chemistry, Jiwaji University, Gwalior.

Manuscript received 18 March 1976; revised 5 July 1976; accepted 20 July 1976.

Investigation for the nucleophilic substitution of di-2, 4-dicbloropbenyl phosphate by water has been carried out at 98° In the range 0.005-4.5M HCI, the ester is found to be reactive via conjugate acid species. The rate constants Increase with increase in acid concentration and attains optimum value in 3.5M acid. Theoretical rates determined from Ionic strength data agree well with the experimentally observed rates. The reaction proceeds with bimolecular nucleophilic attack of water on phosphorus of the conjugate acid species involving P-O fission. The concepts such as kinetic order, Zücker Hammett hypothesis, Bonnet-Olsen's parameters, Arrhenius parameters, solvent effect and solvent isotope effect have been used to give extra support to probable reaction mecanism.