ACID-CATALYZED HYDROLYSIS OF OXETANE

Hydrolysis of oxetane was restudied in aqueous perchloric acid solutions. The rate constants, activation entropy and solvent deuterium isotope effect are in agreement with the literature data, but the log(k(psi)/s(-1)) vs. H-0 acidity function plot is curved, and not linear as reported earlier. The kinetic excess acidity method gives the reasonable pK(SH+) value of -2.75+/-0.19 at 283 K, and the m(not equal) parameter is 1.03+/-0.01, which is in accord only with an A-2 hydrolysis mechanism. An early transition-state probably rationalizes the exceptional isotope effect found (k(H)/k(D)=0.39+/-0.02).