Effects of mixed CH3CN-H2O solvents on rate of intramolecular general base-catalyzed cleavage of ionized phenyl salicylate in the presence of 3-aminopropan-1-ol, 1,2-diaminoethane, and glycine

The effects of mixed CH3CN-H2O solvents on rates of aminolysis of ionized phenyl salicylate, PS-, reveal a nonlinear decrease in the nucleophilic second-order rate constants, k(n)(ms), (for aminolysis) with increase in the content of CH3CN until it becomes approximate to 50%, v/v. The values of k(n)(ms) remain almost unchanged with change in the CH3CN content within 50 to 70 or 80%, v/v. The effects of mixed CH3CN-H2O solvents on pK(a) of leaving group, phenol, and protonated amine nucleophile have been concluded to be the major source for the observed mixed solvent effects on k(n)(ms). (C) 1998 John Wiley & Sons, Inc.