The hydrolysis of pyrrolidine green and some derivatives. Part 2. The kinetics of the hydrolysis of some 3-substituted derivatives of pyrrolidine green

Abstract

Rate constants have been measured for the reactions of hydroxide ion with Pyrrolidine Green and its 3-Me, 3-Br, 3-CF₃, and 3-NO₂ derivatives in aqueous solution. The substituents affect the rate of hydrolysis to an extent linearly related to the appropriate Hammett substituent constant. Thermodynamic parameters ΔH^‡ and ΔS^‡ have been determined for each dye. The existence of an isokinetic relatronship has been established by analysis of Arrhenius plots and confirmed by other methods.