Synthesis and Mechanistic Interpretation of Hydrolytic Dephosphorylation of Monoamidate of 2,4-dichloro aniline phosphate in Acid Media
Abstract
Synthesis of mono 2.4-dichloroanniline phosphate was carried out using POCl3 as phosphorylating reagent and the kinetic study of monoamidate of 2,4-dichloroaniline phosphate was conducted in an acidic medium ranging from 0.01 to 7.0 mol dm-3at a temperature of 50°C. A notable feature of the acid log rate profile was the presence of a rate maximum at 4.0 mol dm-3. The decrease in rate beyond 4.0 mol dm-3 can be explained by either a reduction in the water activity concentration or a favourable impact of ionic strength. The observed rates are in close agreement with the theoretically estimated rates obtained from the second empirical term of the Debye-Huckel equation. Further investigations into ionic strength, temperature variation, and solvent effects were conducted to elucidate the reactive species involved establishing the molecularity of the reaction. The bimolecular nature of the reaction was determined by examining Arrhenius parameter, the Zucker-Hammet hypothesis and Bunnett-Olsen parameters which led to conclude that the phosphate monoester reaction involves P-N bond fission, supported, by the comparison of kinetic rate data.
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