| Abstract: | Hydrolysis of Amides of Phospholinic Acid The acid catalysed hydrolysis of  (= OAP, R = organic substituent) has been investigated kinetically. Provided the pH remains constant, the hydrolysis is a first order reaction. From the temperature dependance of the rate constant the activation energy Ea as well as the thermodynamic data ΔH* and ΔS* have been calculated. In comparison to the compound with R = H aromatic substituents and additional the t-butyl group enhance Ea whilst aliphatic substituents included the benzyl group diminish Ea. The first step of the reaction is a protonation at the oxygen or nitrogen resulting in the formation of an equilibrium. After the determination of the basicity constant KA of some OAPs it was possible to calculate the respective rate constants of the rate determining step of the reactions and the corresponding thermodynamic data EF, ΔH and ΔS . It is assumed that the mechanism of the hydrolysis takes place according to the same scheme which has been assumed for the hydrolysis of cyclic esters of the phosphinic acid by Ugi [1] and colaborators. |
