On the reactivity of organophosphorus compounds. Part III: Application of the Hammett relation to the rates of alkaline hydrolysis of a number of diethyl substituted phenyl phosphates

As part of our program on the reactivity of organophosphorus compounds in nucleophilic substitution reactions the rates of alkaline hydrolysis have been determined for a number of diethyl substituted phenyl phosphates (diethyl phenyl phosphate and eight ortho‐, five meta‐ and thirteen para‐nuclear‐substituted derivatives). The following relationships were observed: — an excellent ϱσ correlation between the log kOH values of diethyl phenyl phosphate and four meta‐substituted derivatives and the “primary” σ values of van Bekkum et al. for meta‐substituents; — a satisfactory correlation between the log kOH values of some ortho‐substituted compounds and Taft's σ* values for ortho‐substituents. Calculated σ values have been compared with van Bekkum's σn values concluding very weak and no mesomeric para interactions for − M and + M substituents respectively.