Properties of diazosulfonates. Part I: The dissociation of methoxybenzenediazosulfonates

The sulfite concentrations in aqueous solutions of methoxybenzenediazosulfonates of pH = 7.8 were determined by dead‐stop end‐point titrations at 25°. ortho ‐Methoxybenzenediazosulfonate dissociates slowly after being dissolved in water. Dissociation and rate constants derived are K = 2.4 × 10 −10 mole l −1 = k a / k b , with k a = 9.0 × 10 −8 s −1 and k b = 375 1 mole −1 s −1 . para ‐Methoxybenzenediazosulfonate is immediately at its equilibrium dissociation in solution with K = 6.6 × 10 −10 mole l −1 , k a = 1.5 × 10 −8 s −1 and k b = 23 1 mole −1 s −1 .