Molecular organization of reactants in the kinetics and catalysis of liquid phase reactions: IX. The catalytic assistance of an alcohol as a component of the medium in the aminolysis of esters

The kinetics of the reaction of p-nitrophenyl acetate with n-butylamine is studied in various solvents containing n-butanol as a component of the medi um. The alcohol is shown to assist the aminolysis by the participation in t he proton transfer from the amine molecule to ester. The stoichiometric com position of the polymolecular complexes of amine with the alcohol participa ting in the reaction is found from the kinetic data at low concentrations o f n-butanol and the data on its association in solutions. At high concentra tions of the alcohol, the kinetic data are described within the framework o f a model that assumes the participation in the reaction of hydroxy groups of the alcohol in the composition of alcohol clusters. The rate of the proc ess is determined by the concentration and sizes of the clusters. The compl ex kinetics of the catalytic assistance of the alcohol as a component of th e medium are quantitatively interpreted according to the concepts on the ro le of the structural organization of the liquid in the kinetics of molecula r reactions in solutions.