文摘
The possible mechanisms of the aminolysis reaction of propylene carbonate with ammonia were investigated by computational techniques. Optimized structures for all the stationary points were examined by employing the B3LYP/6-311++G(d,p) and MP2/6-311++G(d,p) methods. The uncatalyzed, base-catalyzed and acid-catalyzed aminolysis reactions were taken into account. Two possible mechanisms of the concerted process and the addition/elimination stepwise pathway are investigated, and the first stages of the stepwise mechanism for all pathways are the rate-limiting processes. The results indicate that the concerted process of non-catalyzed aminolysis has lower energy barrier in comparison with the stepwise mechanism. Concerning the base-catalyzed and acid-catalyzed aminolysis, the neutral stepwise pathway is more favorable than the concerted mechanism and the energy barriers of all steps are lower than those of the uncatalyzed aminolysis. The solvent effect by a polarized continuum model does not significantly change the conclusion.